Soil stabilization

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

Structural support of lime or cement stabilized subgrade used with flexible pavements

Abstract: Lime or cement stabilizations have been used to modify wet and soft roadbed soils so that the roadbed can carry the load of construction vehicles without excessive rutting. Lime stabilization is recommended for fine-grained and high plasticity soils, and cement stabilization is recommended for coarse-grained and low plasticity soils. The durability and structural benefits of the stabilized road bed soils have been investigated in this study through four tasks. First, the in-situ conditions of stabilized subgrade were investigated using the Dynamic Cone Penetrometer (DCP) test. The results show that the moduli of stabilized soils are generally higher than non-stabilized soils several years after construction. The second task investigated the durability and strength characteristics of stabilized soils through laboratory tests. Unconfined compressive strength, California Bearing Ratio, and resilient modulus of stabilized soils are all higher than non-stabilized soils. After freezing and thawing cycles, the stabilized soils retain more strength and modulus than the non-stabilized soils. The third task evaluated the conditions of 4 test sections on State Route 2 in Erie County, with subgrade stabilized with 6% cement, 5% lime, 3% lime with 3% cement, respectively, and a control section with no stabilization. Pavement deflection measurements were taken during different stages of construction and for each of the 3 years after construction. The backcalculated subgrade moduli show that stabilization increases the subgrade modulus, with the cement treated soil being the strongest initially, followed by the 3% lime plus 3% cement section. However, the lime stabilized subgrade continues to gain strength three years after construction. The cement stabilized section has sandy soils, while the other sections have clayey soils. The fourth task developed a design procedure to quantify the increase in strength and modulus as an "effective" subgrade modulus in order to include the structural benefit of stabilized subgrade in the current pavement thickness design procedure.

Mixed-in-place stabilization of pavement structures with cement and additives

Abstract: The paper describes new developments of mixed-in-place stabilization of (sub-) base courses with cement. This method can be used in road and highway engineering as well as for airport runways. Essential are the mixing capacity of the site equipment, a precise scheduling, and proper suitability and acceptance tests. The minimizing of reflective cracking can be achieved by several methods, whereby micro-crack rolling of the fresh stabilization has proved very effective. This relaxation rolling can be optimized by means of continuous compaction control (CCC). Furthermore, CCC provides complete quality assurance - contrary to conventional random spot checking. The paper also reports on combined stabilizations: cement plus bitumen to minimize reflective cracking and lime plus cement for cohesive soils.

Performance of partially replaced collapsible soil - Field study

Abstract: Soil collapse occurs when increased moisture causes chemical or physical bonds between the soil particles to weaken, which allows the structure of the soil to collapse. Collapsible soils are generally low-density, fine-grained combinations of clay and sand left by mudflows that have dried, leaving tiny air pockets. When the soil is dry, the cemented materials are strong enough to bond the sand particles together. When natural soil becomes wet, moisture alters the cementation structure and the soil’s strength is compromised, causing collapse or subsidence. Based on soil type and density, the potential for encountering collapsible soils throughout most of the project alignment is low. Conditions in arid and semi-arid climates like Borg El Arab, near Alexandria Egypt favor the formation of the most problematic collapsible soils. The behavior and performance of compacted sand replacement over treated collapsible soil by pre-wetting and compaction are investigated in the current study. Field investigation was performed in the form of plate loading tests conducted on compacted sand replacement over improved collapsible soil. Field plate load tests program was developed to explore the effect of compacted sand replacement thickness on collapsibility potential. Treated collapsible soil was replaced with imported cohesionless soil with variable thickness up to footing width. Results proved that the improvement of collapsible soils by sand/crushed stone replacement is possible to control/mitigate their risk potentials against sudden settlement when exposed to water. Replacement soil increases the rate and reduces the amount of footing settlement. For compacted collapsible soils, partial replacement by compacted sand/crushed stone layers decreases collapsibility potential risk. Results also, introduce the development of practical, economical and environmentally safe geochemical methods for collapsible soil stabilization and collapsible risk mitigation.

Laboratory modelling of strength and deformation characteristics of a high swelling soil treated with industrial wastes

Abstract: Presence of swelling soils in the foundations may cause excessive damage to the buildings, pavements and other lightweight structures due to its differential volume changes with the moisture. On the other hand, some of the massively generated industrial wastes offer engineering characteristics, which may be utilized with a twofold benefit of cleaned environment and soil stabilization. In this study, silica fumes and scrap rubber powder from local industry have been mixed with a highly expansive soil in different proportions to improve its strength and deformation characteristics. Furthermore, scanning electron microscope images were studied to understand the effects of additives on the stabilization mechanism of the expansive soils. The analyses of results confirmed that these industrial wastes could markedly improve the undrained shear strength and sufficiently decrease the swelling characteristics of tested soil. A set of empirical correlations have also been proposed to predict both swell potential and pressure that could be subsequently verified through additional experimental data obtained from additional published studies. In essence, the proposed empirical correlations could predict the behaviour of the tested additional data with a standard error of mean well within ±10% that may be suitable for preliminary assessments of most practical sites.

Strength and mechanical behaviour of coir reinforced lime stabilized soil

Abstract: Soil stabilization is an essential engineering process to enhance the geotechnical properties of soils that are not suitable for construction purposes. This study focuses on using coconut coir, a natural fibre to enhance the soil properties. Lime, an activator is added to the reinforced soil to augment its shear strength and durability. An experimental investigation was conducted to demonstrate the effect of coconut coir fibers and lime on the consistency limits, compaction characteristics, unconfined compressive strength, stress-strain behaviour, subgrade strength and durability of the treated soil. The results of the study illustrate that lime stabilization and coir reinforcement improves the unconfined compressive strength, post peak failure strength, controls crack propagation and boosts the tensile strength of the soil. Coir reinforcement provides addition contact surface, improving the soil-fibre interaction and increasing the interlocking between fibre and soil and thereby improve strength. Optimum performance of soil is observed at 1.25% coir fibre inclusion. Coir being a natural product is prone to degradation and to increase the durability of the coir reinforced soil, lime is used. Lime stabilization favourably amends the geotechnical properties of the coir fibre reinforced soil.