Soil stabilization

About: Soil stabilization is a research topic. Over the lifetime, 3161 publications have been published within this topic receiving 48437 citations.

Soil stabilization in pavement structures

Abstract: Five soil samples were selected to represent the subgrade soils commonly stabilized by lime or cement in NCDOT highway construction. The five soils are classified by the AASHTO symbols A-4, A-4, A-5, A-6, and A-7-5 and were labelled as samples DOT-1 to DOT-5. Laboratory tests measured the CBR, resilient modulus, and unconfined compressive strength on samples compacted in the laboratory at three different water contents for each soil. The five soils were compacted without any additive to measure the soil properties for unstabilized soil. The five soils were then mixed with 3%, 4%, and 5% lime before compacting and with 8%, 10%, and 12% cement before compacting. The lime stabilized soils showed the greatest improvement when mixed with 4% lime as the resilient modulus for four of the samples increased by 3 to 5 times. The A-7-5 soil only increased by 1.5 times. The resilient modulus for the cement stabilized soils increased more but without an optimum cement level for all five soils. For soils DOT-1 to DOT-4 the resilient modulus increased by a factor of 5 to 7 times when mixed with cement. The measured resilient moduli were used in a layered elastic analysis to infer the structural layer coefficients by using the resilient vertical strain in the subgrade as a criterion. The structural layer coefficients for lime stabilized soils varied from 0.06 to 0.18 for base course resilient moduli of 30,000 to 40,000 psi. The structural layer coefficients for the cement stabilized soils were determined from the unconfined compressive strengths and varied from 0.12 to 0.18.

Review of soft soils stabilization by grouting and injection methods with different chemical binders

Abstract: Soil stabilization has become one of the useful solutions to treat the soft soils to achieve the required engineering properties and specification so that structures can be placed safely without undergoing large settlements. Soil stabilization by admixture was developed in Japan during 1970s and 1980s. The treated soil has greater strength, reduced compressibility and lower hydraulic conductivity than the original soil. The use of admixture such as lime, cement, oils and bitumen is one of oldest and most widespread method for improving soil. When mixed with soil, it forms a material called soil-cement. The original technique known internationally as the deep mixing method (DMM) was developed simultaneously in Sweden and Japan in the mid-1970s. It is an in-situ soil treatment technology whereby the soil is blended with cementitious and/or other materials. Jet grouting is suitable to be used as the injection method for the DMM. It utilizes a fluid jet (air, water and/or grout) to erode and mix the in-situ soft or loose soils with grout. The grouting method is one of the ground improvement methods suitable for the soft soil. Chemical stabilization is the effective method to improve the soil properties by mixing additives to soils. Usually the additives are cement, lime, fly ash and bituminous material. The chemicals usually used are sodium silicate, acrylamide, N-methylolacrylamide, polyurethane epoxy resins, aminoplasts, phenoplasts, lignosulfonates, among others. The choice of a particular chemical for soil stabilization will depend upon many factors like, purpose, soil strength desired, toxicity, rheology among others. Key words: Injection, jet grouting, chemical grouting, deep mixing method.

Influence of soil stabilizing materials on lead polluted soils using Jet Erosion Tests

Abstract: Solidification/stabilization treatment is usually used to stabilize site of contaminated land. Several common binding materials, such as cement, hydrated lime, and bitumen, were usually utilized as stabilizer materials for contaminated soil and tested by old techniques. Recent studies have been proposed that the high lead (Pb) concentration in soil causes an increase in soil erodibility, which is a major global environmental problem. An excess shear stress model is normally applied to measure soil erodibility based on two empirical soil parameters: critical shear stress (τc) and erodibility coefficient (kd). Jet Erosion Test (JET) is one of recent technique to measure the soil erodibility parameters (τc and kd) in the field as well as in the laboratory. The objective of this study was to investigate the influence of many building materials (cement, hydrated lime, and bitumen) on the stability of an artificially Pb-contaminated soil, using “mini” JET device as a function of measuring soil erodibility parameters (τc and kd). Hence, different percentages of three common Iraqi building materials (cement, hydrated lime, and bitumen) at different curing time were conducted to observe the effect of these materials on soil properties; such as Atterberg limits, dry density, optimum moisture content, and hardness as well as to soil erodibility parameters (τc and kd). The results showed a reduction in kd value with increasing in the percentage of building materials and curing time, while τc values were increased. The ideal mixing ratios of stabilizer materials showed that hardness degree increased by a ratio of 22% to 28.4%, while Atterberg limits either decreased or increased by a ratio of 5% to 28.5%. The results showed that all these materials can improve soil properties of Pb-contaminated soil and the cement was the best stabilizer. This study provides the benefit of using JET device in consume testing time and conserving energy, compared with other conventional techniques usually used for studying soil stabilization.

Soil Stabilization with Calcined Paper Sludge: Laboratory and Field Tests

Abstract: Two investigative stages are presented in this study, which aim to establish basic standards for the use of calcined paper sludge (CPS) in the stabilization of soils. The soils were stabilized with CPS and with mixtures of CPS and cement (C). The total percentage of binder was between 3 and 6% by weight. The blending ratios (by weight) of the CPS:C mixtures were 50∶50 and 25∶75. The first stage took place in the laboratory, and the second stage, in the field, involved in situ stabilization of 250 m of subgrade using dry-mix methods. The bearing capacity of the stabilized soils was determined in the laboratory. In the second stage, the densities of the subgrade were measured in the field following compaction and deflections at 7 days. Furthermore, the evolution of its unconfined compressive strength (UCS) was measured over 90 days. The results reveal optimal mechanical behavior of the stabilized soil at CPS:C ratios of approximately 25∶75.