Predicting Desiccative Degradation of Stabilized Soil Using Regressive Models

Calcium sulfoaluminate cement (CSA) was used to stabilize a type of marine soft soil in Dalian China. Unconfined compressive strength (UCS) of CSA-stabilized soil was tested and compared to ordinary Portland cement (OPC); meanwhile the influence of amounts of gypsum in CSA and cement contents in stabilized soils on the strength of stabilized soils were investigated. X-ray diffraction (XRD) tests were employed to detect generated hydration products, and scanning electron microscopy (SEM) was conducted to analyze microstructures of CSA-stabilized soils. The results showed that UCS of CSA-stabilized soils at 1, 3, and 28 d firstly increased and then decreased with contents of gypsum increasing from 0 to 40 wt.%, and CSA-stabilized soils exhibited the highest UCS when the content of gypsum equaled 25 wt.%. When the mixing amounts of OPC and CSA were the same, CSA-stabilized soils had a significantly higher early strength (1 and 3 d) than OPC. For CSA-stabilized soil with 0 wt.% gypsum, monosulfate (AFm) was detected as a major hydration product. As for CSA-stabilized soil with certain amounts of gypsum, the intensity of ettringite (Aft) was significantly higher than that in the sample hydrating without gypsum, but a tiny peak of AFm also could be detected in the sample with 15 wt.% gypsum at 28 d. Additionally, the intensity of AFt increased with the contents of gypsum increasing from 0 to 25 wt.%. When contents of gypsum increased from 25 to 40 wt.%, the intensity of AFt tended to decrease slightly, and residual gypsum could be detected in the sample with 40 wt.% gypsum at 28 d. In the microstructure of OPC-stabilized soils, hexagonal plate-shaped calcium hydroxide (CH) constituted skeleton structures, and clusters of hydrated calcium silicates (C-S-H) gel adhered to particles of soils. In the microstructure of CSA-stabilized soils, AFt constituted skeleton structures, and the crystalline sizes of ettringite increased with contents of gypsum increasing; meanwhile, clusters of the aluminum hydroxide (AH3) phase could be observed to adhere to particles of soils and strengthen the interaction.

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Utilization of Zeolite to Improve the Behavior of Cement-Stabilized Soil

International Journal of Geosynthetics and Ground Engineering ◽

10.1007/s40891-021-00284-9 ◽

2021 ◽

Vol 7 (2) ◽

Author(s):

MohammadReza ShahriarKian ◽

Shahab Kabiri ◽

Meysam Bayat

Keyword(s):

Stabilized Soil

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An Improved Mechanistic-Empirical Creep Model for Unsaturated Soft and Stabilized Soils

Materials ◽

10.3390/ma14154146 ◽

2021 ◽

Vol 14 (15) ◽

pp. 4146

Author(s):

Xunli Jiang ◽

Zhiyi Huang ◽

Xue Luo

Keyword(s):

Water Content ◽

Unsaturated Soils ◽

Simulation Analysis ◽

Soft Soil ◽

Creep Model ◽

Subgrade Soils ◽

Stabilized Soil ◽

Deformation Behaviors ◽

Creep Models ◽

Moisture Conditions

Soft soils are usually treated to mitigate their engineering problems, such as excessive deformation, and stabilization is one of most popular treatments. Although there are many creep models to characterize the deformation behaviors of soil, there still exist demands for a balance between model accuracy and practical application. Therefore, this paper aims at developing a Mechanistic-Empirical creep model (MEC) for unsaturated soft and stabilized soils. The model considers the stress dependence and incorporates moisture sensitivity using matric suction and shear strength parameters. This formulation is intended to predict the soil creep deformation under arbitrary water content and arbitrary stress conditions. The results show that the MEC model is in good agreement with the experimental data with very high R-squared values. In addition, the model is compared with the other classical creep models for unsaturated soils. While the classical creep models require a different set of parameters when the water content is changed, the MEC model only needs one set of parameters for different stress levels and moisture conditions, which provides significant facilitation for implementation. Finally, a finite element simulation analysis of subgrade soil foundation is performed for different loading levels and moisture conditions. The MEC model is utilized to predict the creep behavior of subgrade soils. Under the same load and moisture level, the deformation of soft soil is largest, followed by lime soil and RHA–lime-stabilized soil, respectively.

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Optimal profile for concave slopes under static and seismic conditions

Canadian Geotechnical Journal ◽

10.1139/cgj-2016-0057 ◽

2016 ◽

Vol 53 (9) ◽

pp. 1522-1532 ◽

Cited By ~ 3

Author(s):

Farshid Vahedifard ◽

Shahriar Shahrokhabadi ◽

Dov Leshchinsky

Keyword(s):

Limit Equilibrium ◽

Stable Configuration ◽

Preliminary Evaluation ◽

Construction Technology ◽

Stability Of Slopes ◽

Optimal Profile ◽

Stabilized Soil ◽

The Stability ◽

Comparison Of The Results ◽

The Impact

This study presents a methodology to determine the stability and optimal profile for slopes with concave cross section under static and seismic conditions. Concave profiles are observed in some natural slopes suggesting that such geometry is a more stable configuration. In this study, the profile of a concave slope was idealized by a circular arc defined by a single variable, the mid-chord offset (MCO). The proposed concave profile formulation was incorporated into a limit equilibrium–based log spiral slope stability method. Stability charts are presented to show the stability number, MCO, and mode of failure for homogeneous slopes corresponding to the most stable configuration under static and pseudostatic conditions. It is shown that concave profiles can significantly improve the stability of slopes. Under seismic conditions, the impact of concavity is most pronounced. Good agreement was demonstrated upon comparison of the results from the proposed method against those attended from a rigorous upper bound limit analysis. The proposed methodology, along with recent advances in construction technology, can be employed to use concave profiles in trenches, open mine excavations, earth retaining systems, and naturally cemented and stabilized soil slopes. The results presented provide a useful tool for preliminary evaluation for adopting such concave profiles in practice.

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EFFECT OF CEMENT CONTENT ON SHEAR PROPERTIES OF LIQUED STABILIZED SOIL REIFORCED BY FIBER MATERIAL

Geosynthetics Engineering Journal ◽

10.5030/jcigsjournal.26.95 ◽

2011 ◽

Vol 26 ◽

pp. 95-100 ◽

Cited By ~ 1

Author(s):

Yukihiro KOHATA ◽

Kiyoshi ITO ◽

Yuta KOYAMA

Keyword(s):

Cement Content ◽

Fiber Material ◽

Shear Properties ◽

Stabilized Soil

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Mechanics Properties of the Lime-Fly Ash Stabilized Soil for Pavement Structures

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.594-597.1445 ◽

2012 ◽

Vol 594-597 ◽

pp. 1445-1448

Author(s):

Tao Cheng ◽

Ke Qin Yan

Keyword(s):

Fly Ash ◽

Unconfined Compressive Strength ◽

Flexible Pavement ◽

Rigid Pavement ◽

Test Compaction ◽

Mix Proportion ◽

Stabilized Soil ◽

Pavement Structures ◽

Optimum Water ◽

Water Contents

Mechanics properties of lime- fly ash stabilized soil are investigated. First, the chemical composition of fly ash are analyzed by spectral analysis test. Compaction experiments of all mix proportion projects are carried out in different water conditions to obtain the optimum water contents. Then the optimum mix proportion is obtained by the unconfined compressive strength and the compression rebound modulus test. Finally, the pavement structures design for a highway of lime- fly ash stabilized soil road sub-base is done. By the comparison, a conclusion can be drawn that lime-fly ash stabilized soil is suitable for flexible pavement or semi-rigid pavement because of its good strength and rigidity which can effectively reduce thickness of the lower pavement and basic deflection.

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Test Study on Road Performance of Soils Stabilized by Liquid Stabilizer in Seasonally Frozen Regions

Advanced Engineering Forum ◽

10.4028/www.scientific.net/aef.5.310 ◽

2012 ◽

Vol 5 ◽

pp. 310-315 ◽

Cited By ~ 2

Author(s):

Yao Chen ◽

Yi Qiu Tan

Keyword(s):

Water Resistance ◽

Base Material ◽

Road Construction ◽

Penetration Resistance ◽

Comprehensive Investigation ◽

Test Study ◽

Stabilized Soil ◽

Road Performance ◽

Modulus Of Resilience ◽

Seasonally Frozen Regions

In seasonally frozen regions, road construction often suffers from low strength,lack of durability, etc. Improving the typical clay’s workability in Changchun with lime and the Base-Seal stabilizer (BS-100) shows promising results. A comprehensive investigation to assess the soil characteristics influence is undertaken, so as the lime and liquid stabilizer (BS-100) content on the physical properties of stabilized soils in seasonally frozen regions. The optimum mix proportions, unconfined compressive strength, splitting strength, modulus of resilience, freeze-thaw action, water resistance and penetration-resistance were outlined. By comparing with current specifications, the Base-Seal stabilized soil as base material has higher early strength, higher after-strength and better frost stability.The results can be applied in road construction in seasonally frozen regions.

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