Fine-Grained Sand Reinforced with Granulated Tire Chips

Ideology of Utilizing waste tires as a material to reinforce sand has been developed recently. Waste tire properties such as flexibility, tensile strength and durability are suitable to use them in engineering applications. Alsodifficulties like fire hazard, environmental contamination occurred by waste tires are the other reasons to explore a way to reuse them in a beneficial manner. Soil used in this study is Babolsar (North of Iran) fine-grained sand. This paper aims to investigate effects of granulated tire chips with sizes in the ranges of 4 to 9 mm on the bearing capacity of sand. For this, a series of model footing tests were conducted on the reinforced sand at relative density of 55%. Sand was reinforced with different tire chips contents 5, 6,7,8,10 and15% by weight.Highest bearing capacity ratio (Ratio of bearing capacity reinforced sand to unreinforced sand) was attained 1.56 with tire chips content of 10% that this amount of tire chips named optimum percentage of tire chips. Stress – settlement graphs showed decrease in settlement of footing by using tire chips that lowest settlement was happened in optimum percentage of tire chips.To investigate the optimum reinforced depth for sand containing optimum tire chips, a few tests were done. Result indicated optimum reinforced depth is 1B (B is the footing width)

Analysis of Soil Liquefaction Potential Through Three Field Tests-Based Methods: A Case Study of Babol City

During earthquakes, ground failure is commonly caused by liquefaction. Thus, assessment of soil liquefaction potential in earthquake-prone regions is a crucial step towards reducing earthquake hazard. Since Babol city in Iran country is located in a high seismic area, estimation of soil liquefaction potential is of great importance in this city. For this purpose, in the present research, using field-based methods and geotechnical data of 60 available boreholes in Babol, three liquefaction microzonation maps were provided. Finally, one comprehensive liquefaction microzonation map was presented for soil of Babol city. The obtained results in this paper are well in line with the previous investigations. The results indicate that application of different field tests in evaluation of liquefaction is necessary

Effect of Zeolite on the Compaction Properties and California Bearing Ratio (CBR) of Cemented Sand

This research investigates the impact of zeolite on the compaction properties and California Bearing Ratio (CBR) of cemented sand. For this purpose, firstly, sand, cement (2, 4, 6, and 8% by the sand dry weight), and zeolite (0%, 30%, 60%, and 90% of cement content, as a replacement material) are mixed. Then, various cylindrical samples with sizes of 101×116 mm and 119×152 mm are prepared for compaction and CBR tests, respectively. After curing for 28 days, the samples are tested according to the standards of compaction and CBR tests. The results depict that the use of zeolite reduces Maximum Dry Density (MDD) while it increases Optimum Moisture Content (OMC) of cemented sand. Furthermore, the inclusion of zeolite up to 30% of cement content contributes to the highest CBR values due to the pozzolanic and chemical reactions. Finally, some correlations with high correlation coefficients are proposed between the CBR and MDD of zeolite-cemented sand

Influence of zeolite on the compaction characteristics and shear strength parameters of cemented sand

It is well known that in geotechnical engineering, soil stabilization using cement is one of the appropriate approaches for enhancing soil characteristics. With respect to zeolite, its impact on the characteristics of cemented soil has not been fully evaluated. Thus, in the current research, a set of laboratory tests including standard Proctor compaction and direct shear tests (DSTs) considering four cement contents (2, 4, 6, and 8% of sand dry weight) and four zeolite contents (0%, 30%, 60%, and 90% of cement percentage as a replacement material) was carried out. The results indicated that the zeolite reduced Maximum Dry Density (MDD) while it increased value of Optimum Moisture Content (OMC) of cemented sand. Through the DSTs, it has been found that the replacement of cement by zeolite up to 30%, leads to the highest values of shear strength parameters due to the occurrence of pozzolanic and chemical reactions, particularly the production of higher amounts of calcium aluminate and calcium silicate hydrates in comparison with zeolite-free samples

Performance of clay based buffer material developed for use in a nuclear fuel waste disposal vault

This study is designed to evaluate water diffusion parameters of clay based buffer material (mixture of clay and sand) used in nuclear fuel waste disposal vault for the following three cases: (a) No volume change in the soil fabric with no air loss. (b) No volume change in the soil fabric with air loss. (c) A complete change in the soil fabric with air loss.One dimensional diffusion type unsaturated flow equation was solved by finite difference method. Powell's optimization technique was used to minimize the material parameters in the proposed diffusion function. The adopted technique makes the use of both theory and experimental data. In this concern several tests have been performed for the three aforementioned conditions to measure the volumetric water content and the soil water potential distributions as a function of time and space.The calculated diffusion parameters were used to predict the volumetric water content and the soil water potential as a function of space and time for longer period of time

Performance of unsaturated clay based barrier under opposing thermal and hydraulic gradients

Experimental and numerical studies of coupled heat and moisture flow induced in an unsaturated soil by simultaneously imposed temperature and hydraulic gradients, in opposite directions, are presented. The experimental portion of the study was designed to provide information on the moisture and temperature distributions in relation to elapsed time and distance from the heat source. Tests were conducted on three different materials: (a) buffer (equal proportion of silica sand and sodium bentonite), (b) backfill (25 percent low swelling clay and 75 percent crushed granite rock), and (c) sand. Each material was compacted to its maximum dry density and optimum water content. The experiments were performed with the application of external hydraulic and temperature gradients in opposite directions. Swelling pressure tests were performed to quantify the local swelling pressure as well as the wall's effect on the resultant reaction pressure. The effect of swelling pressure on hydraulic pressure and local volume change has been studied using the experimental results.In the theoretical part of this research, a numerical solution of the governing coupled heat and mass flow equations was obtained via the implicit finite difference method. The solution was then used in conjunction with Powell's optimization technique to back-calculate the transport coefficients. A sensitivity analysis of the volumetric water content and temperature with respect to the transport coefficient was performed. Using the calculated transport parameters, the moisture content profile was predicted.The experimental results have shown that moisture flows from the hot and cold ends to the middle part of the soil column. The developed local swelling pressure appears to have significant effect on moisture movement and hydraulic pressure. The use of a sand layer between the buffer and waste container has been observed to be very useful in reducing the shrinkage of the buffer material.The numerical results strongly support the dependence of the transport coefficients, in the governing coupled heat and moisture flow equations, on temperature and volumetric water content

Influence of zeolite and cement additions on mechanical behavior of sandy soil

It is well known that the cemented sand is one of economic and environmental topics in soil stabilization. In this instance, a blend of sand, cement and other materials such as fiber, glass, nanoparticle and zeolite can be commercially available and effectively used in soil stabilization in road construction. However, the influence and effectiveness of zeolite on the properties of cemented sand systems have not been completely explored. In this study, based on an experimental program, the effects of zeolite on the characteristics of cemented sands are investigated. Stabilizing agent includes Portland cement of type II and zeolite. Results show the improvements of unconfined compressive strength (UCS) and failure properties of cemented sand when the cement is replaced by zeolite at an optimum proportion of 30% after 28 days. The rate of strength improvement is approximately between 20% and 78%. The efficiency of using zeolite increases with the increases in cement amount and porosity. Finally, a power function of void-cement ratio and zeolite content is demonstrated to be an appropriate method to assess UCS of zeolite-cemented mixtures

Empirical Correlation between Geotechnical and Geophysical Parameters in a Landslide Zone (Case Study: Nargeschal Landslide)

Today, geotechnical and geophysical techniques are used for landslide evaluation. Geotechnical methods provide accurate data, but are time consuming and costly. Geophysical techniques, however, are fast and inexpensive, yet their accuracy is lower than that of the geotechnical methods. Therefore, simultaneous use of geotechnical and geophysical methods provides a suitable solution for landslide evaluation. Availability of geotechnical and geophysical data makes it possible to investigate correlation between different parameters. Correlating geotechnical and geophysical parameters ends up lowering field investigation costs and enhancing subsurface survey speed in a landslide zone. In the present study, in order to evaluate Nargeschal landslide in Iran, ambient noise measurement, ERT survey, and geotechnical investigations were used. Once finished with data processing, the data obtained from geotechnical and geophysical investigations were correlated. These included SPT-N – electrical resistivity, soil moisture content – electrical resistivity, and SPT-N – shear wave velocity correlations. The correlations were examined using two methods, namely Spearman’s coefficient test and least square regression analysis. The results obtained from the two methods were in good agreement with one another. The correlations obtained in this study were of moderate to very strong strength and fell in the range of the results of previous studies. Investigation of the results indicated significant influences of ground water on electrical resistivity and soil stiffness on shear wave velocity. Results of this study can be used for soil classification and determination of mechanical and seismic characteristics of soil across various areas

Effect of granulated rubber on shear strength of fine-grained sand

Review of the literature related to the mixture of shredded tire and sand shows that, despite of the increase in shear strength due to addition of tire chips, granulated rubber causes reduction in shear strength of sand. In this study, the shear behavior of mixtures of fine-grained sand and 1–5 mm granulated rubber is investigated. Sixty direct shear tests were conducted on sand–granulated rubber mixtures with various rubber contents (0%, 5%, 10%, 20% and 30%) at different relative densities (50%, 70% and 90%) and different normal stresses (34.5 kPa, 54.5 kPa, 74.5 kPa and 104.5 kPa). The obtained results show that the granulated rubber improves the shear strength of fine-grained sand at medium relative density and low normal stress. The degree of improvement in shear strength is a function of rubber content, relative density and normal stress. The results show that at relative density of 50%, by adding 5% granulated rubber, the internal friction angle of sand increases from 35.1° to 39.2°. However, at relative densities of 70% and 90%, addition of granulated rubber to sand decreases its internal friction angle. The results also indicate that the behavior of sand becomes more ductile with increasing granulated rubber content. Adding granulated rubber leads to greater yielding strain and less tangent stiffness of sand. The maximum dilation angle decreases with the decrease in granulated rubber content. The stress ratio of sample at critical state (ψ = 0°) decreases with increasing granulated rubber content