230.1R-90.pdf

ACI 230.1R-90 (Reapproved 1997) State-of-the-Art Report on Soil Cement reported by ACI Committee 230 Wayne S. Adaska, Chairman Ara Arman Richard L. De Graffenreid Harry C. Roof Robert T. Barclay John R. Hess Dennis W. Super Theresa J. Casias Robert H. Kuhlman James M. Winford David A. Crocker Paul E. Mueller Anwar E. Z. Wissa Soil cement is a denseiy compacted mixture of portland cement, soil/ 4.4-Flexural strength aggregate, and water. Used primarily as a base material for pave- 4.5-Permeability ments, soil cement is also being used for slope protection, low- 4.6-Shrinkage permeability liners, foundation stabilization, and other applications. 4.7-Layer coefficients and structural numbers This report contains information on applications, material proper- ties, mix proportioning, construction, and quality-control inspection and testing procedures for soil cement.This report 's intent is to pro- Chapter 5-Mix proportioning vide basic information on soil-cement technology with emphasis on 5.1-General current practice regarding design, testing, and construction. 5.2-Proportioning criteria 5.3-Special considerations Keywords: aggregates; base courses; central mixing plant; compacting; con- struction; fine aggregates; foundations; linings; mixing; mix proportioning; moisture content; pavements; portland cements; properties; slope protection; Chapter 6-Construction soil cement; soils; soil stabilization; soil tests; stabilization; tests; vibration. 6.1-General 6.2-Materials handling and mixing CONTENTS 6.3-Compaction 6.4-Finishing Chapter 1-Introduction 6.5-Joints 1.1 -Scope 6.6-Curing and protection 1.2-Definitions Chapter 2-Applications Chapter 7-Quality-control testing and 2.1 -General inspection 2.2-Pavements 7.1 -General 2.3-Slope protection 7.2-Pulverization (mixed in place) 2.4-Liners 7.3-Cement-content control 2.5-Foundation stabilization 7.4-Moisture content 2.6-Miscellaneous applications 7.5 -Mixing uniformity * 7.6-Compaction Chapter 3-Materials 7.7-Lift thickness and surface tolerance 3.1-Soil 3.2-Cement 3.3-Admixtures Chapter 8-References 3.4-Water 8.1-Specified references 8.2-Cited references Chapter 4-Properties 4. l-General 1-INTRODUCTION 4.2-Density 4.3-Compressive strength 1.1-Scope This state-of-the-art report contains information on applications, materials, properties, mix proportioning, ACI Committee Reports, Guides, Standard Practices, and design, construction, and quality-control inspection and Commentaries are intended for guidance in designing, plan- ning, executing, or inspecting construction and in preparing specifications. References to these documents shall not be made in the Project Documents. If items found in these doc- Copyright 0 1990, American Concrete Institute. uments are desired to be a part of the Project Documents, they All rights reserved, including rights of reproduction and use in any form or should be phrased in mandatory language and incorporated by any means, including the making of copies by any photo process, or by any electronic or mechanical device, printed, written, or oral, or recording for sound into the Project Documents. or visual reproduction for use in any knowledge or retrieval system or device, unless permission in writng is obtained from the copyright proprietors. 230.1 R-l 230.1 R-2 ACI COMMITTEE REPORT testing procedures for soil cement. The intent of this 2-APPLICATIONS report is to provide basic information on soil-cement 2.1 -General technology with emphasis on current practice regarding The primary use of soil cement is as a base material mix proportioning, properties, testing, and construc- underlaying bituminous and concrete pavements. Other tion. uses include slope protection for dams and embank- This report does not provide information on fluid or ments; liners for channels, reservoirs, and lagoons; and plastic soil cement, which has a mortarlike consistency mass soil-cement placements for dikes and foundation at time of mixing and placing. Information on this type stabilization. of material is provided by ACI Committee 229 on Controlled Low-Strength Material (CLSM). Roller- 2.2-Pavements compacted concrete (RCC), which is a type of no-slump Since 1915, when a street in Sarasota, Fla. was con- concrete compacted by vibratory roller, is not covered structed using a mixture of shells, sand, and portland in this report. ACI Committee 207 on Mass Concrete cement mixed with a plow and compacted, soil cement has a report available on roller-compacted concrete. has become one of the most widely used forms of soil stabilization for highways. More than 100,000 miles of 1.2-Definitions equivalent 24 ft wide pavement using soil cement have Soil cement-AC1 116R defines soil cement as “a been constructed to date. Soil cement is used mainly as mixture of soil and measured amounts of portland ce- a base for road, street, and airport paving. When used ment and water compacted to a high density.” Soil ce- with a flexible pavement, a hot-mix bituminous wear- ment can be further defined as a material produced by ing surface is normally placed on the soil-cement base. blending, compacting, and curing a mixture of soil/ag- Under concrete pavements, soil cement is used as a base gregate, portland cement, possibly admixtures includ- to prevent pumping of fine-grained subgrade soils un- ing pozzolans, and water to form a hardened material der wet conditions and heavy truck traffic. Further- with specific engineering properties. The soil/aggregate more, a soil-cement base provides a uniform, strong particles are bonded by cement paste, but unlike con- support for the pavement, which will not consolidate crete, the individual particle is not completely coated under traffic and will provide increased load transfer at with cement paste. pavement joints. It also serves as a firm, stable work- Cement content-Cement content is normally ex- ing platform for construction equipment during con- pressed in percentage on a weight or volume basis. The crete placement. cement content by weight is based on the oven-dry Failed flexible pavements have been recycled with ce- weight of soil according to the formula ment, resulting in a new soil-cement base (Fig. 2.1). Recycling increases the strength of the base without re- weight of cement moving the old existing base and subbase materials and Cw = x 100 Oven-dry weight of soil replacing them with large quantities of expensive new base materials. In addition, existing grade lines and The required cement content by weight can be con- drainage can be maintained. If an old bituminous sur- verted to the equivalent cement content by bulk vol- face can be readily pulverized, it can be considered sat- ume, based on a 94-lb U.S. bag of cement, which has a isfactory for inclusion in the soil-cement mixture. If, on loose volume of approximately 1 ft3, using the follow- the other hand, the bituminous surface retains most of ing formula’ its original flexibility, it is normally removed rather than incorporated into the mixture. The thickness of a soil-cement base depends on var- c Y = D - [I+&001 x 100 100 ious factors, including: (1) subgrade strength, (2) pave- ment design period, (3) traffic and loading conditions, 94 including volume and distribution of axle weights, and where (4) thicknesss of concrete or bituminous wearing sur- face. The Portland Cement Association (PCA), 2,3 the Cv = cement content, percent by bulk volume of American Association of State Highway and Transpor- compacted soil cement tation Officials (AASHTO),4 and the U.S. Army Corps D = oven-dry density of soil-cement in lb/ft3 of Engineers (USACE), 5,6 have established methods for Cw = cement content, percent by weight of determining design thickness for soil-cement bases. oven-dry soil Most in-service soil-cement bases are 6 in. thick. This thickness has proved satisfactory for service conditions The criteria used to determine adequate cement fac- associated with secondary roads, residential streets, and tors for soil-cement construction were developed as a light-traffic air fields. A few 4 and 5 in. thick bases percentage of cement by volume in terms of a 94-lb have given good service under favorable conditions of U.S. bag of cement. The cement content by volume in light traffic and strong subgrade support. Many miles terms of other bag weights, such as an 80-lb Canadian of 7 and 8 in. thick soil-cement bases are providing bag, can be determined by substituting 80 for 94 in the good performance in primary and high-traffic second- denominator of the preceding formula. ary pavements. Although soil-cement bases more than more than 300 major soil-cement slope isfactory quality for upstream slope protection was not protection projects have been built in the U. almost 40 years sion of water resource projects in the Great Plains and later (Fig. coastal shorelines.3-Slope protection nal test section at Bonny Reservoir has required very Following World War II. spillways. there was a rapid expan.S. highway and railroad em- ects. placed in successive horizontal layers 6 to 9 ft wide by tant facing. This is referred tion in 1951.9 The origi- 2. High costs Canada. little maintenance and still exists today. less than 50 percent of the cost of riprap and produced tilayered thicknesses up to 32 in. Since 1961. Kansas. In addition to upstream facing of dams. the soil cement is usually with sandy soils could produce a durable erosion-resis. soil for transporting riprap from distant quarries to these cement has provided slope protection for channels. the slope protection ated by waves. reservoirs. like those associated with small lected because of severe natural service conditions cre. ditches.3). and embankments for inland reservoirs. severe applications.1R-3 Fig. 2. South Central regions of the U. adjacent to the slope. and lagoons. Bureau of Reclamation (USBR) initiated bankments. specified soil cement in 1961 as an alternative to riprap The largest soil-cement project worldwide involved for slope protection on Merritt Dam. thick.S. Nebraska. a major research effort to study the suitability of soil For slopes exposed to moderate to severe wave ac- cement as an alternative to conventional riprap. SOIL CEMENT 230. 6 to 9 in. and more than 100 freeze-thaw may consist of a 6 to 9 in. For less shore of Bonny Reservoir in eastern Colorado was se. 2.2). and locally available for many of these projects. far less than the cost savings realized by using soil ce- tute. a total savings of more than $1 million for the two Since 1975. rapid-flowing water. and 1.S.1-Old bituminous mat being scarified and pulverized for incorporation in soil-cement mix 9 in. This method is often tion. constructed in 17 states. sites threatened the economic feasibility of some proj.8 ment over riprap. placed parallel to the slope face. thick are not common. Rock riprap of sat. the USBR was convinced of its suitability and referred to as “plating” (Fig. local soils with portland cement and fly ash have been Performance of these early projects has been good. Soil cement was bid at industrial pavement project3 have been built with mul. the USBR constructed a full-scale test sec. ice. soil-cement base courses incorporating projects. Based tion (effective fetch greater than 1000 ft) or debris-car- on laboratory studies that indicated soil cement made rying.7 Specification guidelines and a Although some repairs have been required for both contractor’s guide for constructing such base courses Merritt and Cheney Dams.2 million yd3 of soil-cement slope protection for a . 2. The U. a few airports and heavy later at Cheney Dam. the repair costs may have been less than if riprap had been used. A test-section location along the southeast to as “stairstep slope protection” (Fig. In addition. thick layer of soil cement cycles per year.2.4). After 10 years of observing the test sec. the cost of the repairs was are available from the Electric Power Research Insti. 2.2-Soil-cement test section at Bonny Reservoir. after 34 years Mini level 3 Not to scale Fig. 2. Colo.4-Soil-cement slope plating for cooling water flume at Florida power plant . 2.230.1 R-4 Fig.3-Soil-cement slope protection showing layered design Fig.. In Tucson. Completed in 1969. for example. 2. prevent liquefaction.S.4-Liners even with G-in. and solid waste weight. includ. for compatibility prior to final design decision. tection for channels and streambanks exposed to lat. Mix proportions for liner applications have been eral flows. ash-settling ponds. In addition to the 21/2 years of exposure. The membrane proved to be puncture-resis- tant to the placement and compaction of soil cement 2. Results has been used to line wastewater-treatment lagoons. After compacting the soil-cement slope protection can be found in References 11 through cover layer.16 imately 50 ft into the embankment. aggregate scattered beneath the mem- Soil cement has served as a low-permeability lining brane. South Africa. showed that with only 5 percent cement content by dry sludge-drying beds. foundation strength and uniform support under large huilla. the 135 acre layer of medium-dense. To prevent scouring fore and after vacuum saturation. One Soil cement has been used as a massive fill to provide of the largest soil-cement-lined projects is Lake Ca. permeable during the exposure period. To appreciate cement that had not been exposed to the wastes. lay- More detailed design information on soil-cement ers of soil cement.Y. static and dynamic design characteristics. it became less the installation of piles or caissons difficult and costly. Environmental Protection Agency possible to obtain a material with enough strength to (EPA) sponsored laboratory tests to evaluate the com. the compressive strength of the soil ce- terior dikes. SOIL CEMENT 230. and the ends extend approx. several cavities immediately below the building made land cement concrete. soil Valley County Water District irrigation system in cement was used to replace an approximately 18 ft thick southern California. der two 900-MW nuclear power plants. tested in which fly ash replaces soil in the soil-cement sional flooding can cause erosion along the normally mixture. (Fig. indi- step fashion up the embankment. a test section was minimum 7-day compressive strength of 750 psi.75 ft wide by 9 in. damage. In ad. membrane can be used.000 ft3/sec at veloci. Arizona. From 1983 to 1988.5-Foundation stabilization ifornia were lined with 4 to 6 in. ment exceeded the compressive strength of similar soil culating cooling water in the reservoir. and ben- existing dry river bottom. Results showed that for these hazardous wastes. and it was landfills. and rubber and plastic 1979. slope protection projects were constructed in this area. liquefaction In addition to water-storage reservoirs. built in 1983 near Apalachin. The exposed slope For hazardous wastes and other impoundments facing is generally trimmed smooth during construction where maximum seepage protection is required. the cement content is increased by two percent.17 material for over 30 years. liquifiable saturated sand un- reservoir bottom has a 6 in. Soil the size of this project.10 ylene (HDPE) membrane placed between two 6-in. Permeabilities significantly less than 1 X 10-7 cm/sec A typical section consists of 7 to 9 ft wide horizontal have been measured for such fly ash-lime-cement mix- layers placed in stairstep fashion along 2:l (horizontal tures. the total distance cating that the specific combination of soil cement and covered would be over 1200 miles. A soft limestone layer containing soil cement hardened considerably and cored like port.18 patibility of a number of lining materials exposed to Soil cement was used in lieu of a pile or caisson various wastes. the freeze-thaw durability. N. if each 6. cohesion increased significantly. the 39 to 52 ft high embankment was designed to wastes.1R-5 7000-acre cooling-water reservoir at the South Texas ing toxic pesticide formulations. along with unconfined compressive strengths be- to vertical) embankment slopes. To demonstrate the construc- ties up to 20 ft/sec. cement. the soil cement is designed for a tion feasibility of the composite liner.000 to 45. The U. certain waste materials should be tested and evaluated Soil cement has been successfully used as slope pro. which indicate good and subsequent undermining of the soil cement. tonite. occa. oil refinery sludges. the membrane was inspected for signs of 13. contain a 15 ft high wave action that would be created no seepage had occurred through soil cement following by hurricane winds of up to 155 mph. The soil cement The alternative to driven foundation supports was to was also exposed to various hazardous wastes. cement was not exposed to acid wastes. Nuclear Power Plant near Houston. Completed in toxic pharmaceutical wastes. After 625 days of exposure to 13 miles of exterior embankment. the 1980 in Tampa. thick soil-cement lining. a number of 1 to 2 acre farm reservoirs in southern Cal. thick soil cement. averaging 27 ft in height. for example. soil cement potential. and durability of the soil cement. To withstand the abrasive force of posite liner consisting of soil cement and a synthetic stormwater flows of 25. guide the recir. Fla. over 50 soil-cement percent portland cement and 2 to 3 percent lime. In addition.14 The tests indicated that after 1 year of foundation for a 38-story office building completed in exposure to leachate from municipal solid wastes. In Koeberg. a terminal-regulating reservoir for the Coachella structures. The sec- dition.5). 2. “fair” in containing caustic petroleum sludges. tion consisted of a 30 and 40 mil high-density polyeth- age points to allow for field variations. The fly ash-cement mixture contains 3 to 6 dry river beds. Is A similar evaluation has been first layer or two is often placed up to 8 ft below the made for liners incorporating fly ash. a com- for appearance. It was rated thick lift were placed end-to-end rather than in stair. excavate the soil beneath the building to the top of . nearly 7 miles of in. these wastes. An extensive and the sand embankments forming the reservoir are laboratory testing program was conducted to determine faced with 2 ft of soil cement normal to the slope. During the mid-1950s. Tex. rial with physical properties similar to the surrounding The clarifiers are square tanks but utilize circular sandstone. of soil cement for mass concrete saved approximately At some locations.19 ment contents vary from 4 to 15 percent by weight with At the Cochiti Dam site in north-central New Mex. the average around 7 percent. thereby minimizing the danger of differen. embankments and dams have been constructed 2. As a result. In addition to providing the necessary or painted to look like any other house. round out the four corners of each tank. a 35 ft deep pocket of low-strength clayey shale Soil cement has been used as stabilized backfill. To operate more efficiently. It provides slope to construct wall systems for residential housing. Worth. The excavated fine sand was commonly made of plywood held together by a system then mixed with cement and returned to the excavation of clamps and whalers.6-Miscellaneous applications entirely of soil cement. The 12 ft thick soil cement mat pacted in 4 to 6 in. The intent of the cement was used as economical backfill material to massive soil-cement placement was to provide a mate. saved $400. the cost of this type of construction the excavation’s walls. The soil cement is then com- in compacted layers. are with lean concrete to provide a uniform surface prior to constructed by placing the damp soil cement into forms soil-cement placement. A layer of tive sandstone core samples.9 million. acts as an impervious core. however. Apalachin. Ce- was needed for sheeting rather than eight. soil cement were constructed in horizontal layers to erage unconfined compressive strength of representa.500 yd3 of soil cement. The soil cement was ramped up can be greater than comparably equipped frame houses. Rammed-earth bearing support for the building. At under a portion of the outlet works conduit was re. N. correct an operational problem for 12 large clarifiers. the soil cement dou. the Dallas Central Wastewater Treatment Plant.000 as compared to either a pile or caisson After the forms are removed. shotcrete was placed over the soil-cement face to serve In 1984. of the sweep. This was done primarily as a isfy the 28-day 1000 psi compressive strength criteria. protection. especially where clay is not avail- $7. just one brace sand and 30 percent noncohesive fine-grained soil.20 ico. 2. thick lifts with a pneumatic tamper. against the sheeting and cut back vertically to act as A typical rammed-earth soil mix consists of 70 percent formwork for the mat pour. precautionary measure to prevent erosion from behind 10 percent cement content was used. limestone.5-Spreading soil cement on membrane at 3:1 slope. crete for a 1200 ft wide spillway foundation mat at Recently. resulting in excessive downtime for main- fined 28-day compressive strengths for the soil cement tenance.230. be cement-stabilized sand. the Texas State Department of Highways Richland Creek Dam near Ft. To sat. as a protective wearing surface.Y. soil cement was used instead of mass con. closely approximating the av. Sludge settles in the corners beyond the reach tial settlement along the length of the conduit. sloped fillets of were just over 1000 psi. About 10 ft and Public Transportation has specified on several of overburden above a solid rock strata was removed projects that the fill behind retained earth-wall systems and replaced with 117.1R-6 ACI COMMITTEE REPORT Fig. and can be built . The cavities within the limestone were filled Rammed-earth walls. sweeps. able.650 yd3 of soil cement. A monolithic soil-cement em- Rammed earth is another name for soil cement used bankment serves several purposes. the wall can be stuccoed foundation. soil placed with 57. homes provide excellent thermal mass insulation prop- bled as a support for the sheeting required to stabilize erties. Uncon. The substitution the wall and/or under the adjacent roadway. which are generally 2 ft thick. 3 of this report. help reduce the cement content. the presence of occasional clay balls may not be and interior uncemented sand fill were constructed to. 200 sieve produce the most coal mine. For unsurfaced soil soil cement to provide a smooth. are of soil cement with the interior zone of the berm con. U. processed crushed or uncrushed sand and long and 20 ft deep.1 miles of interior Some exceptions include organic soils. the 8 to 22 ft high soils are preferred. Iowa. in Some nonplastic fines in the soil can be beneficial. cement-kiln dust. Slot storage higher fines content (material passing No. In 1983. presence of fines is not always detrimental. ding layer of coal. Normally the maximum outer soil-cement edges were trimmed to a finished side nominal size aggregate is limited to 2 in. plasticity index is greater than 8. To minimize erosion to the addition. and imposes a 10 per- of soil cement. which focuses tection and served as the impervious core. During construction. Davis Power Plant near Corpus 3. tains at least 20 percent coarse aggregate (granular ma- erations. The Sarpy Creek storage trough is 750 ft silty sand. Tests including construction was a uniformly graded beach sand.21. and crushed stone. soils containing between 5 and 35 cement in a variety of applications. weathering. the 3. Clay balls have a tendency to form when the At the Louisa Power Plant near Muscatine. Type I or Type II portland for its coal pile. however.5H:1V. highly wear-resistant cement exposed to moderate erosive forces. thick horizontal lifts. Mont.. Granular pacted cement-stabilized beach sand. Types of soil typically used include gravity flow.1-Soil Christi.22 Section 5. Tex. the owner was able to eliminate the bed.1 R-7 on relatively steep slopes due to its inherent shear access to the area for service and operating equipment. discusses the subject the increased shear strength properties of the com.. A smooth exposed surface was obtained by trail. cement structure. usually more difficult to pulverize for proper mixing. crushed lime. and poorly reacting sandy soils. such as surface. sieve.2-Cement almost 100 percent coal recovery. A modified as. However.11 The were stabilized with 12 in. The 15. uniformly graded sands or gravels. Bureau of Reclamation requires that clay balls Several coal-pile storage yards have been constructed greater than 1 in. A shotcrete liner was placed over the 55 percent passing the No. The Sarpy Creek percent fines passing a No. pendence Steam Electric Station near Newark. For pavements and only the exterior face of the coal-retaining berm was other applications not directly exposed to the environ- stabilized with soil cement. The trough cally stabilized. be removed. resulting in a “swiss cheese” appear- ing plates at a 55-deg angle against the edge during ance. Other advantages cited by the utility include 3. By utilizing on special design considerations. Typically. The only locally available material for clays. The 12 in. utilized soil cement in economical soil cement. with at least slope of 50 deg. nonplastic fines in- stone aggregate. slope-protection applications. The soil consisted of a processed. They pulverize and mix more easily embankment was constructed at a relatively steep slope than fine-grained soils and result in more economical of 1. materials. which can weaken the soil-cement structure. of soil cement at the Inde. detrimental to performance. other applications where soil cement is exposed to phalt paving machine was used to place the soil ce. studies by Nussbaum23 Monolithic soil cement and soil-cement-faced berms have shown improved performance where the soil con- have been used to retain coal in stacker-reclaimer op. The individual lift construction. . By stabilizing the area with screenings serve to fill the voids in the soil structure and soil cement. some soils having the construction of a coal storage slot. A monolithic soil-cement embank- ment was used to form the 1 l00-acre cooling water res. circumferential embankment and 2. The reservoir consisted of 6.3 ft thick exterior zone was with granular soil) do not break down during normal stabilized with 6 percent cement. It was constructed entirely satisfactory hardening and.5 miles of Almost all types of soils can be used for soil cement. near Hardin. The 4 ft thick soil cement ment. compacted lifts. strength properties. Ark. 3-MATERIALS ervoir for Barney M. Aggregate gradation requirements are not as restric- tom to 7 ft wide at the top. SOIL CEMENT 230. reduced fire hazard. in the case of clays. soil cement because they require the least amount of Coal-handling and storage facilities have used soil cement.S. highly plastic baffle dikes.500 yd3 of soil cement were gravel. 200 sieve) basically consists of a long V-shaped trough with a re. of poorly reacting sandy soils in more detail. For slope protection or gether in 9 in. The berm at the Council Bluffs Power Station terial retained on a No. 4 sieve). resulting in an estimated savings of $3 million. and low-plasticity have been successfully and economi- claim conveyor at the bottom of the trough. mixing. Soils containing more than 2 percent sidewalls must be at a steep and smooth enough slope organic material are usually considered unacceptable to allow the stored coal to remain in a constant state of for stabilization. a defined perimeter For most applications. 4 sieve. in southwestern Iowa is 840 ft long by 36 ft high and Fine-grained soils generally require more cement for has steep 55 deg side slopes. Ninety-five acres of coal storage yard cent limit on clay balls passing the l-in. clay balls (nodules of clay and silt intermixed exposed soil cement. constructed in horizontal layers 22 ft wide at the bot. the clay balls tend to wash out of the soil- ment. the tive as conventional concrete. and aggregate two 6 in. The ASTM D 4318 are available to identify these problem monolithic soil-cement design provided both slope pro. thick layer was placed in cluding fly ash. and all-weather cement conforming to ASTM C 150 is normally used. In taining 3 percent cement. Moisture contents of soil cement are usually in strength. The flocculating action of the ce- Chemical admixtures are rarely used in soil cement. factors. CH 10-16 13 11-13-15 *Does not include organic or poorly reacting. SP. tion was at or slightly above optimum. However. CH 8-13 10 8-10-12 A-6 CL.2-Density Pozzolans such as fly ash have been used where the Density of soil cement is usually measured in terms advantages outweigh the disadvantages of storing and of dry density. provided matter. Prolonged delays between the mixing of soil cement imum compaction and for hydration of the portland and compaction have an influence on both density and cement. The moisture-density test (ASTM as a cementitious material. the mixture was intermittently mixed several times an torily. SP 5-8 6 4-6-8 A-2 GM. The presence of chlorides in seawater may in. as the clayey portion of the soil in. Cement contents may range 4. the higher the compressive strength 3. 3-5 5 3-5-7 SW. soils. Seawater has been used satisfac. the higher the density. additional cement may be required for severe exposure conditions such as slope-protect&. and water content. (c) uniformity of mixing. including (a) type and proportion of soil.230. Al- ment tends to produce an increase in optimum mois- though research has been conducted in this area. (d) curing conditions. Because of these table provides initial estimates for the mix-proportion. eral factors. while been primarily limited to laboratory studies with few the high specific gravity of the cement relative to the field investigation.4-Water of cohesionless soil-cement mixtures. SM A-l-b GM. A typical moisture-density curve lan.24-29 soil tends to produce a higher density. Felt32 had similar findings but also showed from harmful amounts of alkalies. free strength. Also. Cement requirements vary depending on desired prop. and soil to be used in the application. acids. Studies by West31 showed that a delay of more the range of 10 to 13 percent by weight of oven-dry soil than 2 hr between mixing and compaction results in a cement. MH. SM. may be used. Water is necessary in soil cement to help obtain max. GC. the quantity of cement required increases.Typical cement requirements for various soil types*’ Typical cement Typical range content for Typical cement contents of cement moisture-density for durability tests AASHTO soil ASTM soil requirement. This chapter provides information on sev- eral properties and how these and other factors affect various properties. Adding cement to a soil generally For highly plastic clay soils. a wide range of values for specific properties ing procedures discussed in Chapter 5. or organic that the effect of time delay was minimized. Shen30 showed that for a given cement content. hydrated lime or quick- causes some change in both the optimum moisture con- lime may sometimes be used as a pretreatment to re- tent and maximum dry density for a given compactive duce plasticity and make the soil more friable and sus- effort.3-Admixtures 4. the direction of this change is not ceptible to pulverization prior to mixing with cement.* test (ASTM D 558). is shown in Fig. .1. (ASTM D 559 and D 506). The cementitious materials. In general. Generally. GP. they should comply with D 558) is used to determine proper moisture content ASTM C 618. creases.1 . may exist. pozzo- mixture is compacted. GM. Where pozzolans are used field density control. it has ture content and a decrease in maximum density. (b) compac- reader is cautioned that the cement ranges shown in tion. 3. Table 3. significant decrease in both density and compressive Potable water or other relatively clean water. hour. CH 9-15 12 10-12-14 A-7 MH. although moist density may be used for handling an extra material. SC 5-9 7 5-7-9 A-3 SP 7-l 1 9 7-9-l 1 A-4 CL. SM. 4. classification classification percent by weight percent by weight percent by weight A-l-a GW. 4-PROPERTIES erties and type of soils.1 are not mix-design recommendations. The quantity of cement and pozzolan and density (referred to as optimum moisture content required should be determined through a laboratory and maximum dry density) to which the soil-cement testing program using the specific cement type.1R-8 ACI COMMITTEE REPORT Table 3.1-General from as low as 4 to a high of 16 percent by dry weight The properties of soil cement are influenced by sev- of soil. and the moisture content at the time ‘of compac- crease early strengths. ML 7-12 10 8-10-12 A-5 ML. GP. usually predictable. The and (e) age of the compacted mixture. ’ is the most pending on the type of soil.GRAINED SOILS .. psi values given are representative for a majority of soils f. and split-tension tests have all been used to eval- affected in the same manner as density by degree of uate flexural strength.2-Relationship between cement content and unconfined compressive strength for soil-cement mix- tures Silty soils: AASHTO groups A-4 and A-5 Unified groups ML and CL Clayey soils: AASHTO groups A-6 and A-7 normally used in the United States in soil-cement con- Unified groups MH and CH I 200-400 I 250-600 struction. 115 L 21 C t g z 110 II 0I 1 2 I 6 II 105 I I I IOO. 4. A good become permanently or intermittently saturated during approximation for the flexural strength R is34 their service life and exhibit lower strength under satu- rated conditions. The pressive strengths for soaked. psi . 1. 120 r C .GRAINED SOILS f.“” textural soil groups and include the range of soil types where normally used in soil-cement construction. The range of R = flexural strength.1.CEMENT CONTENT yMaximum density z & Optimum moisture .4. FINE . 4. fifth to one-third of the unconfined compressive Typical ranges of 7.4-Flexural (tensile) strength (modulus of as a criterion for determining minimum cement re. be used to approximate the relationship between com- pressive strength and cement content.1R-9 125 2800 0 COARSE .Ranges of unconfined compressive 0 I I I strengths of soil-cement33 0 5 10 15 20 25 CEMENT CONTENT (% BY WEIGHT) Fig. Flexural strength is about one- compaction and water content.3.1 .Typical moisture-density curve 400 - Table 4.’ = unconfined compressive strength. Compressive strength serves 4. 4.2 shows that a linear relationship can *Specimens moist-cured 7 or 28 days. strength increase is greater for granular soil cement ally measured according to ASTM D 1633. percent Fig. SOIL CEMENT 230. 4. rupture) quirements for proportioning soil cement. 4. Data for some soils are shown in Fig. Fig. 4. It indicates than for fine-grained soil cement. direct-tension strength is directly related to density. soil-cement specimens are ratio of flexural to compressive strength is higher in given in Table 4. then soaked in water prior to strength testing. I 5 10 15 20 25 Moisture content. Because Flexural-beam tests (ASTM D 1635). These data are grouped under broad R = 0. this property is tests.and 28-day unconfined com. the degree of reaction of the soil-cement-water mixture and the rate of hardening. for cement con- tents up to 15 percent and a curing period of 28 days.‘)“. As shown in Fig.UNCONFINED COMPRESSIVE 2400 _ STRENGTH .. Soaking specimens prior to testing low-strength mixtures (up to l/3 fi ) than in high- is recommended since most soil-cement structures may strength mixtures (down to less than l/5 ff ). the widely referenced property of soil cement and is usu. strength.51 (f.3-Compressive strength Curing time influences strength gain differently de- Unconfined compressive strengthf. 1 i:f 60 Fine sand (SP) 100.2 3.6 0.3 7.9 9.5 5 Fine sand (SP) 111. 005 0005 required.7 13..1 i. 4. content.3 6900 #30 (600 .:‘: 10.2 12.:: 21 Fine sand (SP) 101 .7 13.800 (100 percent passing #20 (850 pm): 0 percent passing sand 112. - 117.1 8.o#‘im) (42!4zm) (7.4 12.0 8.3 1.9 2 Silty sand (SM) 112.2 0 750 100 100 91 7 1 .3 E7 *Cement requirement based on ASTM Standard Freeze-Thaw and Wet-Dry Tests for soil-cement mixtures and PCA paving criteria.5 0 : .1 105.0 13.0 0 36 .3 190 105.0 g.6 12.2 10.1 3.8 14.0 8.0 11.2E) m m mm by weight Standard Ottawa 108.9 14. FINE .0 0 16 100 75 lo.8 0 48.230.3 :*: 33 108.8 5.7 115.GRAINED SOILS WITH 10% CEMENT o GRANULAR SOILS 0 c FINE .5 12. 98 115.5 Silty sand (SM) 118.7 0 16.2 560 103.GRAINED SOILS 01 I I I I 10 100 1000 0 500 1000 1500 2ooo 2500 CURING TIME (days) UNCONFINED COMPRESSIVE STRENGTH (psi) Fig.5 Silty sand (SM) 125.9 10.4 5.0 12.0 15.6 .7t4mm) (2.1 100 99 119. 11.8 0 140 100 100 94 2 -.1 Silty sand (SM) 117.9 0 5000 100 100 96 13 12 2 8.3 12. 4.2 1 Fine sand (SP) 101.0 14.8 16. classification lb/ft3 percent percent by weight -6 10 cm/sec (4.6 0 16 98 94 125.5 100.GRAINED SOILS WITH 10% CEMENT .2 13.5 76 Graded Ottawa 103. 11.4 108.2 .4 9:6 E2 Fine sand (SP) 112.300 100 100 28 2-.7 0 5.3 13. 97 115.2 10. urn) .Permeability of cement-treated soils17 Gradation analysis.4-Relationship between unconfined compres- Fig.o 12.3-Effect of curing time on unconfined concrete sive strength and flexural strength of soil-cement compressive strength of some soil-cement mixture34 mixtures34 Table 4.7 11. K coefficient of percent passing Dry Moisture Cement permeability ft Cement* ASTM soil density.5 11.5 11.2 13. content per yr.7 1400 104.9 13.3 5.0 106.0 ::: 21 Silty sand (SM) 100.8 13.5 8.5 I 23 8 100 99 Silty sand (SM) 121.8 0 10 99 97 123.1 R-l 0 ACI COMMITTEE REPORT 500 COARSE . .0 99. - sand 104.8 10.8 6 0 I 360 20 I 99 99 96 6 61 - 109.6 470 107. 15 Less than 400 psi 4.20 350 psi each soil type produces a different crack pattern.1 R-11 Values of tensile strength deduced from the results of flexure.23 Shell and sand with 650 psi age.5-Frequency distribution of various sizes of the hot summer months. corresponding layer thicknesses.D. where a1. degree of Delaware 0. Soil cement made with granular soils pro.20 400-650 psi at slightly below optimum moisture content. The shrinkage and subsequent cracking depend place) on cement content. spaced 2 to Montana 0. and a3 = layer coefficients of surface..37 Soil cement made from Georgia 0. due to the effects of stress concentrations and dif- ferences between moduli in tension and compression.20 400 psi min 10 ft apart). soil type.23 650 psi min duces less shrinkage.30 650 psi min (plant mixed) include keeping the soil-cement surface moist beyond the normal curing periods and placing the soil cement Wisconsin 0. layer coefficient a. 0.15 300 psi (mixed-in-place) results of field data on shrinkage cracking from five 0. . possibly due to shrinkage SIZE OF CRACK OPENING (in. values are thickness4 assigned to each layer of material in the pavement structure to convert actual layer thicknesses into a SN .6-Shrinkage mixed) 0.5-Permeability Permeability of most soils is reduced by the addition of cement.7-Layer coefficients and structural numbers Several different methods are currently being used The following general equation for structural number for pavement design. Table 4.5 shows the Florida 0.a. and is a measure of the relative ability of the material base.3 . New Mexico 0.20 400-650 psi to the compaction plane were 2 to 20 times larger than 0. coefficients for soil cement used by various In multiple-lift construction.2 summarizes results from labora- tory permeability tests conducted on a variety of soil types. water content.) cracks in the soil-cement filling with sediment and the tendency for the cracks to self-heal.15 Less than 400 psi ~____ values for flow normal to the compaction plane.33 Methods 0. 4.17 400-650 psi intervals (usually 10 to 20 ft or more apart).S. This layer coefficient expresses the empirical relationship between SN and thickness D. hairline cracks. Seepage was as much as 10 times greater in the cold winter months than Fig. + a 2D2 + a3D3 structural number SN. Soil Louisiana 0.18 400 psi min 0.15 200 psi min cement made with clays develops higher total shrink. A large-scale seepage test was performed by the U. direct-tension.36 Results indicated a decrease in permeability with time. respectively.20 compaction. 4. 0.20 650 psi min (mixed-in-place) 0. and subbase. In the AASHTO method for reflects the relative impact of the layer coefficient and flexible pavement design.28 with minimum 800 psi (plant 4.20 500 psi (plant mixed) test locations in Australia. a2. Research by State coefficient 0 strength requirement Nussbaum23 has shown permeabilities for flow parallel Alabama 0. but larger cracks spaced at greater 0.12 Less than 400 psi suggested for reducing or minimizing shrinkage cracks Pennsylvania 0. and split-tension tests may dif- fer. The reduced summer seepage shrinkage cracks in soil cement37 was probably caused by thermal expansion which nar- rowed the crack widths and by the presence of algae Table 4. SOIL CEMENT 230. 4. and curing conditions. Bureau of Reclamation on a section of layered stairstep soil cement facing at Lubbock Regulating Reservoir in Texas.23 650 psi min 0. and D1. but crack widths are smaller and individual cracks min more closely spaced (e.Examples of AASHTO layer growth in the cracks. Fig.23 For cement-treated subgrade Cement-treated soils undergo shrinkage during with 800 psi min (mixed-in- drying. For cement-treated base Arizona 0. and D3 = to function as a structural component of the pavement. Research by Radd35 has shown that the split-tension test yields values that do not deviate by more than 13 per- cent from the direct tensile strength.23 650 psi min 0. higher permeability can state DOTs generally be expected along the horizontal surfaces of Layer Compressive the lifts than perpendicluar to the lifts. D2.g. 3. USACE requires mens in the Laboratory that both criteria be met before a stabilized layer can be ASTM D 1633 Test for Compression Strength of used to reduce the required surface thickness in the de- Molded Soil-Cement Cylinders sign of a pavement system. For bank protection. the cement content should be increased two percentage points. values used by state depart.230. SM. respectively.2 . SP 14 A-2 GM. 2. 4.USACE minimum unconfined durability. PI> 10 ments of transportation are given in Table 4. Cement contents sufficient to prevent weight ASTM D 559 Wetting-and-Drying Tests of Com. using the PCA criteria above. compressive strength criteria38 ers. Additional criteria 1.PCA criteria for soil-cement as indicated by wet-dry and freeze-thaw durability tests1 AASHTO Unified soil Maximum allowable weight soil group group loss. and the Type of soil 12 wet-dry or freeze-thaw cycles. permeability may be the principal requirement. Ta. CH 7 A-7 OH.38 The durability and strength re- ASTM D 1632 Making and Curing Soil-Cement quirements for portland cement stabilization are given Compression and Flexure Test Speci.3. CH 7 *10 percent is maximum allowable weight loss for A-2-6 and A-2-7 soils. USACE has an unnumbered draft Engineer Technical letter for in- terim guidance. PI< 10 11 cement layer coefficient a.2-Proportioning The U.1 R-l 2 ACI COMMITTEE REPORT Table 5.1-General The principal structural requirements of a hardened soil-cement mixture are based on adequate strength and Table 5. GP..3 . percent A-l-a GW. SM 14 A-l-b GM. USACE frequently in- ASTM D 2901 Test for Cement Content of Freshly creases the cement content by 1 or 2 percent to account Mixed Soil-Cement for field variations. CH 10 A-6 CL. For water resource applications such as lin. Granular. Army corps of Engi- 5-MIX PROPORTIONING neers. Compressive strength should increase with age of specimen. Maximum water content during the test should be less than the quantity required to saturate the sample at the time of molding. Silt : Clays 6 *Refer to MIL-STD-619B and MIL-STD-621A. The cement content determined as adequate for pavement. SP.S. which indicate the Maximum allowable weight loss after effect of the wearing course. The layer coefficients are actually the average of a set Table 5. Maximum volume changes during durability test should be less than 2 percent of the initial volume. 5. Drop ments.USACE durability requirement38 of multiple regression coefficients. Typical soil- Granular. select material or sociation Soil-Cement Laboratory Handbook1 and by the following ASTM test standards: ASTM D 558 Test for Moisture-Density Relations of Cement Association (PCA) criteria are summarized in Soil-Cement Mixtures Table 5. GP. in Tables 5.” TM 5-822-4.S. ASTM D 1557 Moisture-Density Relations of Soils The U.1 . Minimum unconfined compressive ble 3. MH.1. the base course. U. SC 14* A-3 SP 14 A-4 CL.:““m Flexible pavement Rigid pavement applications. ing are considered adequate to produce a durable soil pacted Soil-Cement Mixtures cement. MH. will be adequate for soil-cement slope protection that is 5 ft or more below the minimum water elevation. GM. lows its technical manual. GC. 39 5. SW.S. losses greater than the values indicated after 12 cycles pacted Soil-Cement Mixtures of wetting-drying-brushing or freezing-thawing-brush- ASTM D 560 Freezing-and-Thawing Tests of Com. stabilized* percent of initial specimen weight subbase on the pavement’s performance. For soil cement that is higher than that elevation. SM.1 indicates typical cement contents for pavement . Subbase course.2 and 5. Detailed test procedures for evaluating mix proportions are given in the Portland Cement As. Bureau of Reclamation (USBR) design cri- Various criteria are used by different organizations to teria for soil-cement slope protection on dams allow determine acceptable mix proportions. Army Corps of Engineers (USACE) fol- and Soil Aggregate Mixtures Using 10. “Soil Stabilization for Pave- lb Rammer and 18-in. The Portland maximum losses during freeze-thaw and wet-dry dura- . ML 10 A-5 ML. 3. 3. All tests can be which use h/d of 2. resistance to sulfate attack differs for cement-treated 5. a in. The county requires the soil cement to have a minimum 7-day compressive strength of 750 psi. These soils require special studies row range of gradations and/or soil types are used.3.00 provides a more completed in 1 day.. 5. 1.0 in.1-Relationship between compressive strength scribes a shortcut test procedure that can be used to de. The cement con- tent is increased two percentage points for additional erosion resistance and to compensate for field varia- tion. lower than 5.1 illustrates the general relationship between cement. The h/d of 2. To facilitate quality-control testing during construction. Ariz. Early research21 showed that organic material compressive strength and durability for soil cement. however. except the 7-day compressive accurate measure of compressive strength from a tech- strength test. nical viewpoint. sulfates will generally attack soil cement. respectively. tion can be made for specimens with h/d of 2. it is USBR’s practice to add two percentage points to the minimum cement content that meets all of the preceding design criteria. In soil-cement testing.15.15) specimens are frequently used. This results in a 7-day compressive strength of about 1000 psi. In addition. some agencies have determined and used suc. the lower 5.3. the county has established an ac. shrinkage and expansive forces that occur in the field. However.2 Compressive strength specimen size-Comp. Fig. treated successfully with normal amounts of portland Fig. To allow for vari- ations in the field. but do not in themselves constitute an indication of a this strength would be higher than needed for most soils poorly reacting sand. will not react nor- sive strength is simplified when materials within a nar. This differs from conventional concrete molds. Using the correction factor for life. USBR requires a minimum compressive strength of 600 psi at 7 days and 875 psi at 28 days. These crite- ria were developed specifically for soil cement slope protection using primarily silty sands. organic content greater than 2 percent or having a pH sign.00. a compres.41 have indicated that the the wet-dry and freeze-thaw tests.1 R-13 bility tests of 8 and 6 percent.15.3. Studies sive strength requirement generally based on results of by Cordon and Sherwood40.10. cer- It is common practice. The studies specimens obtained from molds commonly available in showed that sulfate-clay reactions are more detrimental soil laboratories and used for other soil-cement tests. It of an acidic nature usually had an adverse effect on soil is apparent from these curves that a compressive cement. 5.3 Poorly reacting sandy soils-Occasionally. than sulfate-cement reactions. The only tests required are a sieve analysis. and durability of soil cement based on Portland Ce- 1 termine the cement content for sandy soils. a sandy soil with an and would result in a conservative and more costly de. resulting in deterioration These test specimens are 4. a result. coarse-grained and fine-grained soils and is a function ressive strength tests are frequently conducted on test of the clay and sulfate concentrations. Relatively small samples are needed. in height with a height-to-diameter (h/d) ratio of moisture-density test. The study showed that organic content and pH strength of 800 psi would be adequate for all soils. crete. in all probability. both strength and durability re. SOIL CEMENT 230. I I I I ceptance criterion based on a l-day compressive 20 40 60 80 1' strength test. in diameter and 4.4 Sulfate resistance-As with conventional con- cessfully. 5. since it reduces complex stress condi- tions that may occur during crushing of lower h/d 5. The determination of a suitable design compres. and a compressive strength test. As prior to use in soil cement. for a particular type of material. however. The proce. mally with cement.00 by the amount of cement needed to hold the mass together multiplying the compressive strength value by a factor permanently and to maintain stability under the of 1. 5. ment Association durability criteria dure uses charts developed from previous tests on sim- ilar soils.11 Pima County. ASTM D 559 and D 560 are standard test methods concrete given in ASTM C 42.3. The PCA Soil-Cement Laboratory Handbook1 de.1 Strength versus durability-In many soil-ce. For the local soils typically used.584 of fine-grained soil cement more rapidly than coarse- . Most of the ment applications. h/d (1. to use compressive tain types of sandy soils are encountered that cannot be strength to determine the minimum cement content. the % OF SAMPLES PASSING l-day strength is generally between 50 to 60 percent of ASTM FREEZE-THAW & WET-DRY TESTS the 7-day value. uses a considerable amount of soil cement for streambank slope protection. an approximate correc- that are conducted to determine.3-Special considerations specimens. compressive strength values given in this report are quirements must be met to achieve satisfactory service based on h/d = 1. for a particular soil. mixing at less than optimum moisture content minimizes the chances for cement balls to form. all soft or wet subgrade areas are located and corrected.42-44 that discuss soil-cement construction methods for var. moisture content Fig.1 Mixed in place. 6.2. Specifications on soil-cement con. organic soils.Windrow-type traveling pugmill mixing soil mixer cement from windrows of soil material . tent of soil-cement mixtures may be more beneficial a heavy rainfall that occurs after most of the water has than changing to a sulfate-resistant type of cement. For single-shaft mixers. 6. light rainfall should not delay construction. However. and aggregates larger than 3 in. from granular to fine-grained. should be removed. rain usually will not harm it. increasing the cement con.2).13. 6. the soil is shaped to the approximate final lines and grades prior to mixing. the soil cement a. Windrow-type pugmill least 40 F and rising.1R-14 ACI COMMITTEE REPORT grained soil cement.45-47 central mixing plant.1 and 6. Proper moisture content aids in pulveriza- tion. Almost all types of soil. 6. 2. Transverse single-shaft mixer ceed with construction when the air temperature is at b. For fine-grained soils.1. Continuous-flow-type pugmill should be protected from freezing for at least 7 days. In-place traveling mixers is below 45 F.2. All deleterious material such as stumps. 6.2-Mixing chamber of a transverse single-shaft Fig. a. 6. a 6. If rain falls during ce- ment-spreading operations.3). However. Windrow-type pugmills are generally lim- ited to nonplastic to slightly plastic granular soils. spreading should be stopped and the cement already spread should be 6-CONSTRUCTION quickly mixed into the soil mass. Also. Several references are available8. Central mixing plant pected to reach the freezing point. multiple passes are required zation. a common practice is to pro. 1 Transverse single-shaft mixer processing soil near optimum may be necessary for effective pulveri- cement in place.2-Materials handling and mixing ious applications. therefore. cured material.1 Soil preparation-During grading opera- tions. Mixing with borrow materials may be performed with single-shaft or windrow-type pugmill mixers (Fig.1-General begin immediately and continue until the soil cement is In the construction of soil cement. Soil cement is either mixed in place or mixed in a struction are also readily available. Rotary-drum mixer of water equivalent to 1 to 1 l/ in. After the mixture has been obtain a thoroughly mixed. the objective is to completely compacted. and compacted. 6. Fig. The typical types of mixing Soil cement should not be mixed or placed when the equipment are: soil or subgrade is frozen or when the air temperature 1. For granular soils.3. can be ad- equately pulverized and mixed with transverse single- shaft mixers. of rain. been added can be detrimental. adequately compacted. Batch-type pugmill Soil-cement construction typically requires the addition c. roots. Compaction should 6. When the air temperature is ex. .Mixing operations with subgrade materials are performed with transverse sin- gle-shaft-type mixers (Fig. b.230. 50 then picks up the soil and cement and dry-mixes them 14. compacted compacted soil cement soil cement ize friable soils.63 point.0 3. for small projects.5 1 1.1.25 width and depth of treatment and on the capacity of 11. slippage can be overcome by using cleats on the spreader wheels.38 4.50 cessing.88 number and size of windrows needed depend on the 11. however. or in lb of cement per ft3 of compacted soil cement.0 5. forward speed.5-Mechanical cement spreader attached to bulk being treated.38 6. Cement content. The 10. 5.5 5.63 uniform cross section.0 9. Forward speed must be slow and even. Cement spread.2 Cement application-Cement is generally distributed in bulk using a mechanical spreader (two examples of which are shown in Fig. the mechanical spreader must be operated at uniform speed with a rel- atively constant level of cement in the hopper. This is usu. 6.13 ment content. Although pipe cement-spreaders attached to ce- ment-transport trucks have been used in some areas with mixed results.0 12. The spreader must have adequate traction to produce a uni- form cement spread.5) or.0 .0 8. and thickness.0 10.5 10.25 7. 6. even. 6.75 13. 6. When borrow materials are 6.2. When operating in loose sands or gravel. water is added through spray nozzles and the re. 16.1 .1 R-15 6. The primary objective of the cement-spreading operation is to achieve uniform distribution of the ce- ment in the proper proportions. The amount of cement required is specified as a percentage by weight of oven-dry soil. moisture content.0 7.13 slightly trenched prepared windrow. In-place mixing efficiency. may be less than that obtained in the laboratory. of mined in the laboratory testing program.0 11. A mixing machine 14.4-Mechanical cement spreader attached to pneumatically from the truck through an air-separator dump truck cyclone that dissipates the air pressure. lb/yd2/in.88 15. Agricultural-type equipment is not recommended due to relatively poor mixing uni- formity. by hand-placing individual cement bags. Nonuniform windrows cause variations in ce. This reduced efficiency is Table 6.63 12.3 Pulverization and mixing-Single-shaft mixers are typically utilized to pulverize and mix ce- ment with subgrade soils. Sometimes a motor grader or loader pulls the truck to maintain this slow. may need 3. Pulverization and mixing difficulties increase with higher fines content and plasticity of the soils Fig.Cement spread requirement51 sometimes compensated for by increasing the cement content by 1 or 2 percentage points from that deter. At that 15. a windrow spreader can be used to proportion the K 6. The mechanical cement-spreader can also be attached di- rectly behind a bulk-cement truck. Nonfriable soils.4 and 6.5 4. it then falls into the hopper of the spreader.25 with the first few paddles in the mixing drum.2. lb/ft3 of thickness of Windrow-type traveling mixing machines will pulver. as measured cement transport truck by the strength of the treated soil.5 7.1.13 i-i 4. 12.1 can be used to determine quantities of cement per yd2 of soil-cement placement.5 8.5 preliminary pulverizing for proper mixing. The prepared soil is bladed into windrows and 6. E 7.75 material. Traction can be aided by wetting and rolling the soil before spreading the cement.0 the mixing machine.5 10. 4. mechanical spreaders are generally preferred. SOILNCEMENT 230.88 a “proportioning” device is pulled along to provide a 7. To obtain a uniform cement spread.50 10. Table 6. Cement is moved Fig.5 E8 Cement is spread on top of a partially flattened or 13.0 used.75 ally done before the soil is placed in windrows for pro. 8). Such materials do cement. cement. Produc.48 If the material in the borrow area varies with depth.2 Central plant mixing-Central mixing plants moval of some oversize clay balls and other large par- are normally used for projects involving borrow mate. silo with surge hopper. shafts equipped with paddles along each shaft (Fig. a conveyor belt to deliver the factorily. A strikeoff at.6.1 Borrow material-Soil borrow sources are A pugmill mixing chamber consists of two parallel usually located near the construction site. and ficul to pulverize.twin screw -Storage h o p p e r Fig. 6. The U. if excavated material is dumped at the base of the stockpile. a cement pugmills and rotary-drum mixers have been used satis.230. mesh (Fig. 6. In some cases. 6.6). either continuous-flow tinuous-flow pugmill plant is shown in Fig. A typ- or batch.Vibrating screen removing oversized material a vertical cut of the stockpile. 6.2.2 Mixing-The objective is to produce a ing clay lenses should be avoided because they are dif.1 R-16 ACI COMMITTEE REPORT posits are generally variable to an extent and do not contain consistent. 6. a mixing method is the continuous-flow pugmill mixer. A front-end loader can then be used to load the soil feed. the most common central plant mixing soil and cement to the mixing chambers. As the borrow material is excavated it should be maining paddles complete the mixing. Although batch ical plant consists of a soil bin or stockpile.2. or cemented conglomerates. 6.2. Granular borrow materials are generally used be.2. full- face cuts should be made with the excavation ma- chinery. Cement storoqe silo- Retaining wall - Water meter Vane feeder (feeds cement Pug mill mixer continuous flow. rials. and rotary-drum mixers. store the mixed soil cement prior to loading (Fig. Bureau of Reclamation recommends the following procedure for handling borrow materia1. uniform materials throughout. or dif- fers from one spot to another. For example. loads from different lo- cations in the borrow area should be mixed. 6.S. and a holding or gob hopper to temporarily 800 t/hr. Mixing for uniformity of gradation and moisture can also be done as the material is pushed into the stockpile.7. Alternating the loads from different parts of the borrow area helps to blend soil gradations in the stockpile.2. ticles can be done by screening through 1 to 1 %-in. not adequately break down in a pugmill mixer. This selective excavation insures that some material from each layer is obtained in each cut. tached to the mixing machine spreads the mixed soil cobbles. There are two basic types of central water in the correct proportions. soil can be further blended at the stockpile. Natural de. Clayey soils or materials contain.7-Diagram of continuous-flow central plant for mixing soil cement . A diagram of a con- plant mixers-pugmill mixers. it can be pushed up the stockpile with a bulldozer. If the material varies laterally across the borrow area. This tends to mix Fig. a water-storage tank for adding water during tion rates with this type of mixer vary between 200 and mixing. thorough and intimate mixture of the soil. which causes further from soil portion of mixture mixing of any layers that might exist in the pile. chamber. After the material has been excavated. checked for unsuitable material such as clay lenses. handling and mixing. Re- 6. selective excavation may cause of their low cement requirements and ease in be necessary to avoid excessive clay lenses. but not wet. Using a motor grader or spreader box at. Narrower layers can also be placed using the conveyor system. The dry Some pavers are equipped with one or more tamping cement should be applied at about 1 lb/yd2 to a mois- bars.9). Mud and debris tracked onto a surface will sig- subgrade and all adjacent surfaces should be moistened nificantly reduce bonding.2. earthen ramps are constructed at in- tervals along the slope to enable trucks to reach the layer to be placed. 1. 6. strength have already been described in Section 4. is determined from contractor experience or trial-and- error methods.2. until it is covered with the next forming to the design grade and cross section. Haul time is usu- ally limited to 30 min.2. paction. Other methods which have prior to placing soil cement. Spreading may also be done with asphalt-type pavers. a 8 to 9 in. Use of either dry cement or cement slurry. For example. 6. such as the South Texas Nuclear Power Plant. flow cen tral mixing plant ment should be placed on a firm subgrade. No more than 60 min should elapse between the start of moist- mixing and the start of compaction. finishing. Soil cement is tened surface immediately prior to placement. moist.4 Placing and spreading-The mixed soil ce. and in a quantity that will produce a com. Thorough blending in the mixer is very important. This relationship varies slightly with the with a power broom to provide a roughened surface type of soil. Material feed. as used for slope protection. After the soil cement has set. brushing the surface of about 6 in. ally completed within 2 hr of initial mixing.50 methods. and the length of mixing time is used to control this factor. This removes the necessity for ramp construction and truck maneu- vering. method of placement and degree of com. and the soil cement is moved through the mixer by the pitch of the paddles. sential that each completed surface remain clean and pacted layer of uniform thickness and density con. rear and bottom dump trucks Fig. since the width needed to facilitate the haul trucks is eliminated. It is es. and provides a cleaner end-product. Compacting. ’ struction. At large-volume projects. pugmill tilt. The soil cement can be delivered either from above or below directly to a spreader box. a conveyor system can be used to deliver the soil cement to the spreader. normally 2 ft thick and spaced about 300 to 400 ft apart. The ce- usually placed in a layer 25 to 50 percent thicker than ment slurry mix should have a water-cement ratio of the final compacted thickness. without segregation. and curing fol. Fig. Some specifications dictate the minimum blending time. The actual thickness of the loosely spread layer 4. The twin-shafts rotate in opposite directions.Typical continuous-flow central mixing plant are often equipped with protective covers.1 R-l 7 6. mental effects of delayed compaction on density and cessive layers of soil cement is an important require. depending on the efficiency of the mixer.8. The layer. continuous 6. SOIL CEMENT 230. For multiple-layer stairstep construction. Usually 30 sec is specified. been effective in improving bond between layers in- There is a wide variety of spreading devices and clude the following:49.80. No ment for applications such as slope protection.2. Use of chemical retarding agents.2. Compaction begins as soon as possible and is gener. which provide initial compaction. 6. al- though satisfactory blending has been achieved in shorter periods. 2.70 to 0. about 0.5 Bonding successive layers--Bonding suc. section is left unworked for longer than 30 min during .2. The detri- 6.3-Compaction low the same procedures as for mixed-in-place con. loosely placed layer will produce a compacted thickness 3. These are constructed at a 45 deg horizontal angle to the slope. belt speed. and paddle pitch are adjusted to optimize the amount of mixing in the pugmill.9-Mixing paddles of a twin-shaft. layers.3 Transporting-To reduce evaporation losses during hot. windy conditions and to protect against sudden showers. 6. texture. Minimizing time between placement of successive tached to a dozer are the most commonly used means.2. The fresh soil cement is left slightly high a minimum of between 95 and 98 percent of maximum until final rolling. For such multiple-layer con- ment. particularly for granular soils.230. and spall. grade. Additionally. In most cases. is often allowed on the completed soil thicknesses. and greater contact pressure. Moisture loss by evaporation during compac. The general rule is to use the the presence of water. Light local layer thicknesses generally range from 6 to 9 in. proven successful. The sheepsfoot roller ally staggered to prevent long continuous joints through is often followed by a multiple-wheel.6-Curing and protection To obtain adequate compaction. Generally. mixed soil cement is then compacted against the con- tions require soil cement to be uniformly compacted to struction joint. and Before the bituminous material is applied. spring tooth. Freshly termined by ASTM D 558 or D-1557. a 3 to 7 day curing greatest contact pressure that will not exceed the bear. For stairstepped em- bankment applications. A thin surface layer of com.1 R-18 ACI COMMITTEE REPORT spiketooth harrow. For good bond. cement immediately after construction. quired.15 to 0. period is required. the surface cross section. Regardless of the lift thickness and compaction equip. roller for finishing. 6.* The scarification ter precedes the bituminous coating. has throughout the lift. or lowed on the soil cement during the curing period. should be special attention to insure that joints are vertical and replaced with light applications of water. Water-sprinkling and bituminous coating are two ment used. Frequently. it is desirable to apply sand over the bituminous coating to minimize tracking of the bituminous material. however. flange welded to steel-wheel roller This is normally done using the toe of a motor grader or dozer. including cut- ting back the uncompacted edges and using special at- tachments on compaction equipment (Fig. 6. a light application of wa- potential surface compaction planes. Sprinkling the surface with compacted layer achieve the specified minimum density water.5-Joints When work stoppages occur for intervals longer than the specified time limits for fresh soil cement. nail drag. motor grader and rerolled. several methods have been used to finish the exposed edges of each lift. it is sometimes neces. Electronic. nous material should not be applied to any surfaces pacted soil cement may not adhere properly to these areas and in time may where bonding of subsequent soil-cement layers is re- fracture. For granular soils. 6. Proper curing of soil cement is important because sary to operate the rollers with ballast to produce strength gain is dependent upon time. Compacted ier than rubber-tired rollers is prohibited. the fundamental requirement is that the popular methods of curing. final surface compaction is performed using a nonvibrating steel-wheeled roller or a rubber-tired roller. the surface of the emulsion. For soils containing an appreciable quantity of gravel. thoroughly compacted. vibratory steel- wheeled or heavy rubber-tired rollers are generally used.10). the soil ce- ment is commonly sealed with an emulsified asphalt. joints are usu- compaction of fine-grained soils. soil cement is shaped to the design line. Joint construction requires tion.4-Finishing The rate of application is dependent on the particular As compaction nears completion. compacted at or near optimum moisture content as de. loosen. that material in the joint area is adequately mixed and Various types of rollers have been used for soil ce. For the construction joint. Following scarification. Most specifica. rubber-tired the structure.30 gal/yd2. 6. automatic fine graders may be used on soil-cement bases for pavements when very tight tolerances are required. Tamping or sheepsfoot rollers are used for initial structions as stairstepped embankments. can be com. when it is trimmed to grade with the density. the soil-cement mixture should be dry or unmixed material is present on the joint edge. the base layer should be rough and damp. together with light rolling to seal the surface. scarification to remove imprints left by equipment or loose material. Greater traffic. bituminous curing should not be . provided the pacted with heavy equipment designed for thicker lifts. In bituminous curing. scarification may not be necessary. temperature. curing coat is not damaged. during which time equipment heav- ing capacity of the soil-cement mixture.10-Compacting outer edge with rounded steel verse joints are trimmed to form straight vertical joints. the surface may require lift of the soil cement should be moist and free of dry. indicated by a graying of the surface. 6. The principles governing com. but typically varies from 0. freshly mixed soil cement is ready for placement against pacting the same soil without cement treatment. be easy to clean before resuming placement. If traffic is al- can be done with a weeder. Retrimming and brooming may be necessary. a check is made to assure that no maximum density. Joints made in this way will be strong and will compaction operations. When the paction of soil cement are the same as those for com. trans- Fig. Bitumi- *Surface compaction planes are smooth areas left near the surface by the wheels of equipment or by motor grader blades. exclusive of gravel or stone retained on these be reduced by additional pulverization and air drying. the canvas with cement is care- Percent No. wet weights of mate. The percentage of moisture in the tion of moist mixing. Spot check-A sheet of canvas. When bulk cement is follow51 being used. Field inspection of soil-cement construction involves controlling the following factors: 1. The 7. 4 sieve and 100 percent pass the near optimum moisture content. plastic tarps. A check on the accuracy of No. The 4. Cement content 3.466require that. the check is made in two ways: 1. Adding lime to highly plastic soils to reduce plas- cannot be adequately pulverized in a central plant. 80 percent of the soil-cement soil at the time of cement application should be at or mixture pass the No. or in extreme cases by the addition of lime. oretical area. Slower forward speed of the mixing machine Most soils require minimum pulverization before 2. it must assure that the contractor has per- formed work in accordance with the plans and specifi- cations. Excess moisture may l-in. Any gravel or stone 7. 4 sieve are weighed separately and their dry weights the cement spread is necessary to insure that the proper determined. Pulverization/gradation 2.1R-19 applied on soil-cement linings for ponds or reservoirs which will be used to hold aquatic life. is placed ahead of the cement spreader. which the known quantity of cement The wet-weight measurements are reasonably accurate should have covered. 7-QUALITY CONTROL TESTING AND INSPECTION 7.1-General Quality control is essential to assure that the final product will be adequate for its intended use. This actual area is then compared with the the- rials are often used instead of the corrected dry weights. Prewetting and premixing the soil before process- keys to pulverization of clayey soils are proper mois. . Overall check-The distance or area is measured over which a truckload of cement of known weight is Note that for practical purposes. Curing References 48 and 51 provide excellent information on quality-control inspection and testing of soil cement and permit immediate adjustments in pulverization and during construction. Moisture content 4. Addi- tionally. Additional passes of the mixing machine processing starts. The spreader is x 100 pulverization = Dry weight of total then adjusted if necessary and the procedure repeated sample exclusive of gravel until the correct spread per yd2 is obtained.3. sieves. spread. mixing procedures if necessary. SOIL CEMENT 230. Soil cement must be protected from freezing during the curing period.3-Cement-content control retained on the sieve is picked out and discarded. 4 sieve 2. Compaction vas to check on quantity of cement spread 6. straw. After the mixture passing spreader has passed. usually 1 yd2 in Dry weight of soil-cement area. Soil that contains excessive moisture will not mix PCA specifications45. Replacing worn mixer teeth quire a considerable amount of preliminary work. Mixing uniformity Fig. sieve. retained on No. or moist earth. Lift thickness and surface tolerance 7.1).2-Pulverization (mixed in place) 1.1-Weighing cement collected on 1 yd2 of can- 5.1 Mixed in place-Cement is normally placed us- clay lumps retained and the pulverized soil passing the ing bulk cement spreaders. Since clayey soils 5. The degree of pulverization is calculated as quantity is actually being applied. use is restricted to mixed-in-place construction. readily with cement. which consists of screening a representative sample of soil cement through a No. 7. Insulation blankets. at the comple. the heavier clay soils re. However. Pulverization can be improved by: 7. Curing can also be accomplished by covering the compacted soil cement with wet burlap. 7. their ticity and improve workability. 4 sieve. or soil cover are commonly used. 3. ing begins ture control and proper equipment. 4 sieve fully picked up and weighed (Fig. This is checked by doing a pulverization test. 2 Central mixing plant-In a central mixing-plant or D 1557). Typically. During this same period. ventional or microwave-oven drying. About 2 percent additional moisture may be ferred to the mixer. plants are cali- with the canvas. The plant is then operated with only cement During compaction and finishing. mined. and optimum moisture content and the moisture content of water for each batch are weighed before being trans. The approximate percentage of water cement is mixed in a batch-type pugmill or rotary-drum added to the soil is equal to the difference between the mixing plant. the surface of the feeding onto the main conveyor belt. On small jobs. the proper quantities of soil. bagged cement is sometimes used.3. very light fog- discharged. 7. known as optimum operation. as evidenced by is adjusted until the correct amount of cement is being graying of the surface. Checks of the main conveyor belt. The plant is operated with only soil feeding onto pieces with little or no crumbling (Fig. cement. brated daily at the beginning of a project. moisture content. enough to dampen the hands when it is squeezed in a rectly from the cement feeder into a truck or suitable tight cast. and periodi- ter checking the distance over which each truckload is cally thereafter. This moisture content. The bags should be spaced at approximately equal trans. the spreader is first adjusted at the start of It may be necessary to calibrate the mixing plant at construction after checking the cement spread per yd2 various operating speeds. 7. It is important to keep a continuous check on in the operation. Both the soil and cement are weighed and water on the hands while mixtures below optimum will the cement feeder is adjusted until the correct amount tend to crumble easily. it is necessary to proportion the cement and moisture. the soil.1R-20 ACI COMMITTEE REPORT Generally. With the plant operating. plant calibration may be used. Then slight adjustments are made af. cement is diverted di. to assure that no change has occurred spread.230. An estimate of the moisture content of a soil-cement 1. Positions can be spotted compaction and for hydration of the cement. If the mixture is near optimum of cement is discharged. The cement feeder soil-cement mixture may become dry. two methods of ing. When soil construction. A mix- plant for a given period of time and collected in a ture near or at optimum moisture content is just moist truck. determined by the moisture-density test (ASTM D 558 7. The soil on a selected length of actual moisture content can be made daily. soil is run through the mixture can be made by observation and feel. proper moisture content of the cement-treated soil is vals to mark the transverse and longitudinal rows. cement-spreading operations. spray applications of water are made to bring the mois- Fig. is used as a guide for field control during soil before they enter the mixing chamber. for evaporation that normally occurs during process- For a continuous-flow mixing plant. The by flags or markers fastened to ropes at proper inter. When this occurs. 7. the cast can be broken into two 2. using con- conveyor belt is collected and its dry weight is deter. Mixtures above optimum will leave excess container.2).4-Moisture content verse and longitudinal intervals that will insure the Proper moisture content is necessary for adequate proper percentage of cement.2-Soil cement at optimum moisture casts readily when squeezed in the hand and can be broken into two pieces without crumbling . These types of plants are calibrated added to account for hydration of the dry cement and simply by checking the accuracy of the weight scales. When the mixture is of tions.1 Mixed in place-A thorough mixture of pul. specified thickness is attained. In addition. Comparing in. frequently. side of a freshly cut face of newly compacted soil ce. moist.1-21 ture content back to optimum. Depth of elevation to within 0. Since some of these standards are revised tests are made immediately after rolling. 7. Thickness can also be checked cracks and surface dusting. Proper moisture con. Generally.5. the user of place densities with the results of maximum density re. the density re. the survey techniques. Lift thickness is usually 7.5R-89 Roller Compacted Mass Concrete . about % in. For pavements. or by dig- tent of the compacted soil cement is evidenced by a ging small holes in the fresh soil cement to determine smooth. diameter being treated. more critical for pavements than for embankment ap- verized soil. depending on the application. of up to 5/8 in. exceed % in. SOIL CEMENT 230.2 Central mix plant.5 cm/sec percent of maximum density. It can also be checked at the place- ment area in a manner similar to the method used for mixed-in-place construction. digging trenches or a series of holes at regular intervals 7.7-Lift thickness and surface tolerance 7. or with surveying equipment. 1 mile=1. Routine depth checks are made during mixing op. and water is necessary to make plications. 1lb/yd3=0. 7. Usually 20 to 1 in. Army Corps of Engineers typically requires that devia- a final check on mixing uniformity and depth can be tions from the plane of a soil-cement base course not made using a 2 percent solution of phenolphthalein. Where heavy clay soils are Engineers typically tests thickness with a 3 in.1-Specified references 2. a departure from design grade cium-rich soil) will retain its natural color. the U. adjustments in compaction procedures that may be re- quired to insure compliance with job specifications.5.S.5-Mixing uniformity strength testing if required. The mixing time necessary CONVERSION FACTORS to achieve an intimate uniform mixture will depend on 1 ft=0. by coring the hardened soil cement. Balloon method (ASTM D 2167) below with their serial designation. with the sand cone or the balloon method. To provide mixing is usually checked at the same time as uniform.S. A mixture that has a streaked controls only the soil-cement embankment crest road appearance has not been mixed sufficiently. 1 acre=0.7. Army Corps of high-quality soil cement. This provides a small diameter core for measuring thickness and for 7. The such as Caltrans. The soil cement will turn pinkish-red while the mum departure from a 12-ft or 10-ft straightedge to untreated soil and subgrade material (unless it is cal. The prepared.Compacted lift thickness is American Concrete Institute usually checked when performing field-density checks 207.454 kg 30 sec of mixing are required. The U. although lift elevation may be monitored with uniform color and texture from top to bottom. this document should check directly with the sponsor- sults from the field moisture-density test indicates any ing group if it is desired to refer to the latest edition. the uniformity is usually checked visually at the mixing plant.2.4 mm 1 lb=1.For central-plant-mixed soil cement. generally in minor detail only.1 Lift thickness.=25. The U.6-Compaction 1lb/ft3 = 16. The most common methods for determining in-place density are: 8-REFERENCES 1.305 m the soil gradation and mixing plant used. Other agencies.895 kPa 7. is usually allowed.01 ft of design grade. tightly knit. compacted surface free of the bottom of treatment. The standards listed In-place densities are determined daily at frequencies were the latest effort at the time this document was that vary widely. Most state transportation departments limit the maxi- ment.2 Surface tolerance-Surface tolerances are usu- for the full depth of treatment and then inspecting the ally not specified for soil-cement embankment applica- color of the exposed material. a reasonably smooth surface for pavement sections. smoothness is usually measured with a 10-ft or 12-ft erations and following compaction to assure that the straightedge.4047 ha quirements range from 95 to 100 percent of the maxi- mum density of the cement-treated soil as determined by the moisture-density test (ASTM D 558 or D 1557). Nuclear method (ASTM D 2922 and D 3017) 8.S.61 km 1 psi=6. in 12 ft using a straightedge placed per- The phenolphthalein solution can be squirted down the pendicular to the centerline at about 50-ft intervals. ity. require that thickness measurements uniformity of all soil-cement mixtures is checked by be taken at intervals not to exceed 1000 linear ft. Bureau of Reclamation mixture is satisfactory. pulverization tests should be conducted core for every 500 yd2 of soil cement. Sand-cone method (ASTM D 1556) The standards referred to in this document are listed 3.7. cement. prior to compaction as described in Section 7. Following compaction.5933 kg/m3 timum moisture content to some specified minimum 1 ft/secc=30.02 kg/m3 The soil-cement mixture is compacted at or near op. U.. trial Vehicles. 8 pp.C. Paper No. pp. U.”Bulletin No. Bureau of Reclamation. 1975. Casias. 1958. Alain.” Information Sheet No. 204. Catton. sociation. Density Relations of Soils and Soil-Ag. 47.“Soil-Cement for Embankment Dams. Tucson.Embankment Dams. “Dam Construction and Facing with Soil-Cement. Denver. Portland Ce- ment Association. Committee on Large Dams.W.. Portland Cement Association. Soil-Cement Slope Protection..” Bulletin No. Cement Concrete 9. Epps. GT3. Nussbaum. 16 25. “Soil-Cement Applications and Use in Pima County for Flood D 559-82 Standard Methods for Wetting-and.. clear Methods (Shallow Depth) 21. Electric Power Research C 595-86 Standard Specification for Blended Hy. by Nuclear Methods (Shallow Depth) 22.” Pim a County Department of Transportation and Drying Tests of Compacted Soil-Cement Flood Control District. Amer- D 1635-87 Standard Test Method for Flexural ican Society of Civil Engineers. Highway Research Board. AFWL-TR-73-150. “Fly Ash Construction Manual for Road and Site Applica- C 618-89 Standard Specification for Fly Ash and tions. Fine Homebuilding. D. K. Skokie.. Report No.1 R-22 MANUAL OF CONCRETE PRACTICE ASTM 5. 1984. 8th International Coal Ash Utilization Symposium.” Publication No. E. and Gallaway. 1975. J. Reser- D 2167-84 Standard Test Method for Density and voirs. 1971. ment Mixtures. “United States Air Force Soil Stabilization Index System-A Plastic Limit. p. and Lagoons. Use as a Mineral Admixture in Portland Oct. 62 pp. 27.. Streets. Skokie. Theodore R. 1986.2-Cited references RD0l0W. Dupas. 1969. Mixtures 11. CS-5362. 26. 1979.” Research and Development Bulletin No. 263.“Low Permeability Liners Incorporating ders Fly Ash. ”Information Sheet No.” gregate Mixtures Using 1 O-lb (4. K. 35-39. Skokie. “Thickness Design of Soil-Cement Pavements for Heavy Indus. T. pp.. 13 . Kirkland Air Force Base. Washington. cials. E. G. 106-108. Mar. 267. Usmen Mumtaz A. .54-kg) Publication No. sity Relations of Soil-Cement Mixtures 10. 2. 105. N. 1986. 1986. 10 pp.. V. tion... letin No.C.. ment Mixtures 12. Air Force Weapons Soils Laboratory. “Effect of Soil and Calcium . Portland Cement Association.. D 1632-87 Standard Methods of Making and Curing 15. Washington. Strength of Soil-Cement Cylinders 17. 1986. P. 1986. and Howard. TMS-825-2 . Publication ” No. Aug. and Colley..C. 23. A. Hansen. 1986. Office of Solid Waste and Emergency Re- Rammer and 18-in .. M. Miles D..” Report No. “Soil-Cement for Facing Slopes and Lining Channels. D. Palo Alto. IS173W Portland Cement As- D 1556-82 Standard Test Method for Density of Soil sociation.. 2: Contractor’s Guide. Moretti./Electric Power Research Institute.S..C. Revised June 1986.” Bul- D 1557-78 Standard Test Methods for Moisture.C. D 1633-84 Standard Test Method for Compressive 1987. Highway Research Board. 24..” Engineering 1966.S.S. Chapter 17.. “Soil-Cement Laboratory Handbook. (457-mm ) Drop sources.” Disposal and Utilization of Electric Utility Wastes. 1980. Walks and Open-Stor- C 42-87 Standard Test Method for Obtaining and age Areas. “Flexible Pavements for Roads. Charles J. 14 pp. Strength of Molded Soil-Cement Cylin. Feb. tent of Soil and Soil-Aggregate in Place Washington. A. . Bureau of Reclama- Thawing Tests of Compacted Soil-Ce. “Development of a Test D3017-78 Standard Test Method for Moisture Con. and Pecker.. 28. EB068S. 2. B. AASHTO Guide for Design of Pavement Structures 1986. 419-436. J. Strength of Soil-Cement Base. 1: Specification Guidelines. Design Standards No. SW870. 12 pp. draulic Cements 8.. Mar. Unit Weight of Soil in-Place by the Rub- 18. 46-50. ASCE. IS126W. Institute. 3. pp. tion. Berglund. M. Portland Cement As.” Proceedings. V. “Thickness Design for Soil-Cement Pavements. and Plasticity Index of Validation. 54. 1960.S.“Development of Fly Ash Liners for Waste Soil-Cement Compression and Flexure Disposal Sites. D. D.” Proceedings.” Engineering Bulletin No. Apr. Publication No.“Addition of Calcium Chloride Increases EB052S. and Felt. Portland Cement Association. D. IS187S. Electric Power Research Institute. 1988. No. Denver.. Biswas.” Engineering News Record. C 150-89 Standard Specification for Portland Ce. V. “Static and Dynamic ber Balloon Method Properties of Sand-Cement. 3. T. 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Elapsed Time after Mixing on the Compaction and Strength of Soil. Army Corps of Engineers. Moultrop. Highway Research Board. 64 pp. D. Lagoons. West. Washington.C. 1988.. 40 pp.” Highway Research 41. “Bonding Study on Layered Soil-Cement. 1962. tion.” Re- tion. Kendall. “Laboratory Investigation into the Effects of 1977. “Study of Soil Cement with Chemical Addi. Monismith. 108. C. 212 pp. Marchall.. 1943. “Resistance of Soil-Cement Exposed to Sulfates. 1954. 1. Aug. EBOO3S. Sheet No. Proceedings. ISO52.” Highway Research No. Cement Mixtures.” Geotechnique. William A. tion. 1955. U. “Tensile Sept. 4 pp. 1959. “Bonding Roller-Compacted Concrete Layers. J. 1987.” Bulletin No.C. Bureau of Reclamation. 9. Nacci. Transportation Research Board.” Report No. Texas.” Bulletin No.. Highway Research Board. 1983. pp. 47. U. V.