Unconfined Compressive Strength of Aqueous Polymer-Modified Saline Soil

The reinforcement and durability of loess are of great importance for road performance. In this study, a self-designed grouting system and newly permeable polymers were adopted to investigate the mechanical properties and durability of solidified loess (SL), considering different dry densities and water contents. The unconfined compression test and piezocone penetration (CPTU) test were used to examine the mechanical properties. The mechanism of the loess solidified by permeable polymer was analyzed from the micro-level by SEM, MIP, and XRD tests. The test results show that the effect of polymer grouting is obvious, the unconfined compressive strength (UCS) of the SL after grouting is as high as 3.05–5.42 MPa; it is 11.83–20.99 times that of unsolidified loess (UL). The UCS of the SL after grouting is inversely proportional to the dry densities and water contents. After 56 days of immersion, the SL still shows a high compressive strength. The additional erosion of the SL was not caused by the salt solution; the durability is significantly better than that of cement mixing soil. The sensitivity of various factors on the UCS of the SL are service environment > water content > dry density. The SEM tests clearly show that the gel formed by the reaction of the polymer with water on the surface of soil particles makes the bond of soil particles tighter. It can be observed from the MIP test that the cumulative mercury of SL was 0.115 mL/g, which was 33.72% of UL (0.341 mL/g), and the cumulative mercury of SL after immersion in water and salt solutions was 0.183 mL/g and 0.175 mL/g, which was 53.7% and 51.3% of UL (0.341 mL/g), respectively. The XRD results show that there are no other new mineral components produced after grouting and the spacing between crystalline planes decreases, which proves that permeable polymer grouting makes the soil denser and does not erode the soil particles.

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“…This is consistent with the results observed by the SEM test. This conclusion is also consistent with Zhu’s findings [ 48 ].…”

Section: Resultssupporting

confidence: 93%

Study on Mechanical Properties of Permeable Polymer Treated Loess

et al. 2022

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“…This could be attributed to the inability of the lime to produce insufficient Ca 2+ ions to participate in cation exchange and pozzolanic reactions [18]. However, it is only natural for the UCS of stabilized soil to increase with increasing curing time [19]. Unlike saline soil, the UCS of combined lime-and-slag base stabilized soils significantly increased over time, but there was a slow increment in UCS of soil treated with 6% lime between 14 to 28 days.…”

Section: Unconfined Compressive Strengthmentioning

confidence: 99%

Stabilization of High Sulfate-Saline Soil with Lime, Ground Granulated Blast Furnace Slag (GGBFS), and Basic Oxygen Furnace Slag (BOFS)

Balogun,

Abzal,

Kissambinova

et al. 2023

KEM

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Saline soil is an inferior and special material consisting of fine soil particles and possesses poor engineering properties. The swelling, salt heaving, and corrosive behaviors of this soil render it unsuitable for pavement construction due to its deteriorating effects. To use this soil as a subgrade material in the roadway, this soil needs to meet various engineering standard criteria such as deformation, sulfate reduction, strength, and durability for use as subgrade material. Hence, the soil underwent careful stabilization using designed proportions of chemical additives such as lime and slag-based materials. The paper studied the feasibility of using slag-based materials (by-products of the steelmaking process) such as ground granulated blast furnace slag (GGBFS) and basic oxygen furnace slag (BOFS) with lime in stabilizing sulfate-saline soil. On this premise, four designed mixtures, which include saline soil (control), [soil+6% lime], [soil+4% lime+2% (50% GGBFS+50% BOFS)], and [soil+4%lime+2% (70% GGBFS+30% BOFS)] for use to determine their various geotechnical and durability properties. The experimental program for determining these properties included proctor compaction, unconfined compressive strength, three-dimensional (3-D) swelling, and dielectric constant tests. As a result, the laboratory test findings have revealed that adding GGBFS and BOFS to the lime-treated saline soil decreased the maximum dry density, enhanced the strength parameter, and reduced the soil's volumetric swelling and moisture susceptibility.

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“…Both actions by the polymer increased the ability of the soil particles to connect with each other; therefore, the permeability of the soil decreased; water affects the strength of the soil in a much reduced manner, and the compactness of the soil increases. As a result, the strength of the soil is significantly improved [17,26].…”

Section: Microscopic Mechanism Of Silt Solidification Induced By the Polymermentioning

confidence: 99%

Strength and Solidification Mechanism of Silt Solidified by Polyurethane

Wang

Xia

et al. 2020

Advances in Civil Engineering

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To determine the mechanism and strength characteristics of solidification of silt by a permeable polyurethane grouting material, the effects of polymer content, soil moisture, and immersion time on the unconfined compressive strength (UCS) of the silt have been studied. The results showed that the permeable polymer grouting material can significantly improve the performance of silt: (1) A higher amount of polymer produced a greater strength in the solidified soil. (2) The strength of the solidified soil increased as the immersion time was increased. (3) Moisture in the soil was not conducive to improving the strength of the solidified soil. The X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDS) have proven that polyurethane does not react with the silt, but they could improve the strength of the silt through physical action. Mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM) were performed to find that polymers can reduce soil porosity, and the addition of polyurethane improved the strength of the silt mainly through adhesion, wrapping, filling, and bridging.

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Unconfined Compressive Strength of Aqueous Polymer-Modified Saline Soil

Cited by 11 publications

References 33 publications

Study on Mechanical Properties of Permeable Polymer Treated Loess

Study on Mechanical Properties of Permeable Polymer Treated Loess

Stabilization of High Sulfate-Saline Soil with Lime, Ground Granulated Blast Furnace Slag (GGBFS), and Basic Oxygen Furnace Slag (BOFS)

Strength and Solidification Mechanism of Silt Solidified by Polyurethane

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