Strength Characteristics of Clay–Rubber Waste Mixtures in Low-Frequency Cyclic Triaxial Tests

Jastrzębska, Małgorzata; Tokarz, Krzysztof

doi:10.3390/min11030315

Cited by 16 publications

(14 citation statements)

References 54 publications

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“…Many authors pay attention to the fact that the main factor influencing the resilient modulus of untreated granular soils is the stress level, inter alia [4,[9][10][11][12][13], both confining pressure and applied axial stress. This phenomenon was also stated in the case of cohesive soils [14][15][16][17]. In all cases, the resilient modulus increased significantly with the confining pressure and marginally with the repeated axial stress.…”

Section: Introductionsupporting

confidence: 63%

Resilient Response of Cement-Treated Coarse Post-Glacial Soil to Cyclic Load

2021

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Stabilisation with cement is an effective way to increase the stiffness of base and subbase layers and to improve the rutting of subgrade. The aim of the study is to investigate the effect of different percentages of cement additives (1.5%, 3.0%, 4.5% and 6.0%) on the resilient modulus of coarse-grained soil used on road foundations. The influence of the compaction method, the standard Proctor and the modified Proctor, as well as the sample curing time is analysed. The cement addition significantly increases the resilient modulus and reduces the resilient axial strain. Extending the curing time from 7 to 28 days also improves the resilient modulus. The change in the compaction energy from standard to modified does not increase the resilient modulus of the stabilised gravelly sand due to its compaction characteristics. The test results of the resilient modulus of the gravelly sand stabilised with cement indicate the possibility of using it as a material for the road base and subbase due to meeting the AASHTO requirements. However, the non-stabilised gravelly sand does not meet the above requirements. It has been sheared during cyclic tests at the first load sequence, regardless of the compaction method.

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Section: Introductionsupporting

confidence: 63%

Resilient Response of Cement-Treated Coarse Post-Glacial Soil to Cyclic Load

2021

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“…Based on the above analysis, it can be concluded that the increase in compaction enhances the shear stress [37]. (6) According to the comparison of the shear strength indices of soil samples under different working conditions, the influence of water content control on the c and φ is obviously greater than that of compaction degree control, and it is difficult to reach a compaction degree of 93% during soil preparation. Choosing compaction degree as the control index of the project in the actual process of the project will not only increase the construction difficulty of the project and affect the construction progress, but the required compaction machinery will further increase the construction cost and increase the project investment.…”

Section: Discussionmentioning

confidence: 99%

“…The specific steps of the direct shear test are as follows: 1 ⃝ First, Vaseline is applied to the inner wall of the ring cutter to ensure smooth demolding; 2 ⃝ red clay samples with different compaction degrees and moisture contents are prepared using the compaction method; 3 ⃝ the ring knife sample is placed in the shear box with a piece of permeable stone and wax paper placed on both sides to prevent moisture loss, and a fixed pin is inserted to temporarily prevent the relative displacement of the upper and lower boxes; 4 ⃝ the edge of the ring knife is moved upward, the top edge of the ring knife is aligned with the shallow groove on the top surface of the upper box, and a bulldozer plug is used to gently press it into the shear box, cover the box cover, and adjust the vertical and horizontal pressure gauges; 5 ⃝ the shear rate is adjusted to 0.800 mm/min, four sets of vertical pressures are set in the control system to 50 kPa, 100 kPa, 150 kPa, and 200 kPa, stopping when the shear deformation is set to 8 mm; and 6 ⃝ data are recorded.…”

Section: Test Proceduresmentioning

confidence: 99%

“…However, in humid and rainy climates, it is difficult to reduce the natural moisture content of red clay to near the optimal moisture content through sun exposure to achieve the corresponding compaction control standards. However, using improvement or replacement methods can cause significant cost increases and environmental pollution [ 4 , 5 , 6 ]. Therefore, roadbed construction in red clay areas can easily lead to roadbed settlement, shoulder collapse, slope instability, and other engineering defects [ 7 , 8 , 9 ].…”

Section: Introductionmentioning

confidence: 99%

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Influence Mechanism of Water Content and Compaction Degree on Shear Strength of Red Clay with High Liquid Limit

Feng,

Teng,

Wang

2023

Materials

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To investigate the influencing factors and mechanisms of shear strength of red clay with a high liquid limit, which was selected at different milepost locations based on the Nanning Bobai Nabu Section Project of the Nanning Zhanjiang Expressway, the basic physical properties of red clay were determined using a liquid plastic limit test, compaction test, inductively coupled plasma optical emission spectrometer (ICP-OES), and X-ray fully automatic diffractometer (XRD). Red clay with a high liquid limit was selected. Furthermore, the direct shear test was used to study the effect of different water contents and compaction degrees on the shear strength. The experimental results demonstrate that under the same compaction degree, the shear stress of the soil sample increases significantly with an increase in normal stress, and the greater the water content, the smaller the shear stress of the soil sample. At 200 kPa, the shear strength of soil samples with 24% water content is 57%, 46%, and 35% of the shear strength of soil samples with 15% water content under different compaction degrees(K) of 86%, 90%, and 93%, respectively. Under the same moisture content, the shear stress of the soil sample shows an increasing trend with an increase in the degree of compaction, and the greater the compaction degrees, the greater the shear stress of the soil sample. The cohesion c and internal friction angle φ of soil samples increase with an increase in the compaction degree, but the increase in cohesion c is also affected by the water content. Under the condition of low water content, the cohesion c of soil samples can be increased by 1.06 times when the water content is 15% and by 0.47 times when the water content is 18%. Under the condition of high water content, the cohesion c of soil samples with 21% water content only increases by 0.3 times, and that with 24% water content only increases by 0.35 times.

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“…Rubber waste from car tires can be used for this purpose, according to the rule "end-of-life tires" (ELT). Each such new application requires research [18,24,50]. Among the tests performed, direct shear tests [6,28,45], unconfined compression tests or triaxial tests [1,18,46] dominate.…”

Section: Introductionmentioning

confidence: 99%

Application of Clay–rubber Mixtures for the Transportation Geotechnics—the Numerical Analysis

Jastrzębska,

Łupieżowiec

2023

Studia Geotechnica Et Mechanica

Self Cite

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The use of waste materials (including rubber) in industry is one of the most important issues in terms of environmental protection. One of such applications is the use of soil–rubber mixtures in backfills or lower layers of embankments or road structures. The numerical analyses of the behavior of a clay–rubber mixture layer built into a road embankment are presented in this article. An elastic-perfectly plastic model with a Coulomb–Mohr yield surface was used in the finite element analysis. The parameters of soil–rubber mixtures adopted for the analysis were estimated on the basis of triaxial tests: monotonic (UU—unconsolidated undrained, and CU—consolidated undrained) and cyclic (CU) performed with low frequency (f = 0,001 Hz). The triaxial tests were carried out on mixtures of kaolin (K) and red clay (RC) with the addition of 1–5 mm rubber granulate (G) in the amount of 5–25% by weight. Numerical analyses included a static plate load test (VSS) of a layer made of a rubber–soil mixture built into the embankment and testing the stability of embankments using the c–ϕ strength reduction procedure. The results of laboratory tests confirm the necessity of testing soil–rubber mixtures each time before their use in embankments. The observed overall decrease in shear strength and stiffness of the tested material is variable and depends on the type of soil and the content of rubber waste. Satisfactory results of the analysis were obtained, both in terms of the values of layer stiffness modules and slope safety factors, which allows for the conclusion of the possibility of using soil–rubber mixtures (with the recommended granulate addition up to 30% by weight) in the layers of road embankments and (depending on the road class) in the lower layers of the pavement structure.

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Strength Characteristics of Clay–Rubber Waste Mixtures in Low-Frequency Cyclic Triaxial Tests

Cited by 16 publications

References 54 publications

Resilient Response of Cement-Treated Coarse Post-Glacial Soil to Cyclic Load

Resilient Response of Cement-Treated Coarse Post-Glacial Soil to Cyclic Load

Influence Mechanism of Water Content and Compaction Degree on Shear Strength of Red Clay with High Liquid Limit

Application of Clay–rubber Mixtures for the Transportation Geotechnics—the Numerical Analysis

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