Materials such as waste tire chips were widely used to improve the strength of soil. The objective of this study is to discuss the residual strength or steady-state behavior of sand-waste tire chip mixtures. A series of undrained monotonic triaxial compression tests were conducted on reconstituted saturated specimens of sand and sand-tire chip mixtures with variation in the tire-chip contents from 0 to 4 percentages by dry weight of soil. The specimens are prepared using dry deposition method of preparation. The influence on residual resistance of varying confining pressure (100, 200, and 300 kPa) and sand mixture relative density (40, 65, and 80%) were evaluated. Tests results showed that by increasing the tire chip contents, the residual strength increased and steady-state lines move to the right of log Sus-e diagram. Also, the residual resistance improvement induced by tire chip inclusions was found to be sensitive to the relative density of samples and applied confining pressure.

Recently, mixtures of clay-tire chips are used as construction material in civil engineering projects. With respect to the tending for using these materials, it is necessary to know their mechanical behavior. Thereby, a number of undrained monotonic triaxial tests are carried out on the specimens of pure clay and clay-tire chip mixtures. Mixed specimens prepared by mixing pure clay with 10%, 20%, and 30% tire chips in weight. The results of the tests indicate that shear strength and pore water pressure due to shearing depend on the amount of tire-chips and clay type. As dependent on the clay type used in the mixtures, there is an optimum content for tire-chips to mix with the clay.

Excessive production and stockpile of scrap tires cause some environmental and sanitary risks throughout the world. To manage these materials, possible use of soil-tire mixtures has been recently propounded in civil engineering projects. A few studies previously have been conducted to evaluate behavior of clay-tire mixtures, while swelling properties, consolidation and settlement characteristics of this type of mixtures are not known admirably. For this purpose, a number of clay-tire chips mixtures were prepared (by adding 10%, 20%, and 30% tire-chips to the clay), and compaction and oedometric consolidation tests are carried out on them. The results show that adding tire-chips to the clay, reduces swelling potential of the mixtures, while the free swelling and swelling pressure of specimen consist of 30% tire-chips is negligible.Also, size of the tire-chips may affect the values of free swelling and swelling pressure. In addition, the results of oedometric consolidation tests indicate that when the tire content increases, compression and swelling indices of the specimens decrease and increase, respectively. Moreover, the settlement behavior of the specimens depends on the tire-chips content and size of the chips.

Attempts to use waster rubber powder as an adsorbent of pollutants in wastewater treatment applications is an environmentally friendly, efficient and novel method, especially in the tire industry wastewater treatment process. This study evaluated the efficiency of waste tire rubber powder in adsorbing the tire industry wastewater. The rubber and The wastewater were prepared from Kavir Qom Co. and Artawheel Tire Co., respectively. Comparison of UV-vis spectrophotometer results of the nontreated wastewater with the wastewater data after adsorption under various thermal and temporal conditions indicated that the tire powder adsorbent has the necessary efficiency for treating the tire industry wastewater. Examination of data with pseudo-first- and second-order kinetic models also confirmed the adsorbent’s efficiency and showed that the second-order kinetic model had a good correspondence with the obtained results.

One method of determining evapotranspiration is zero flux plane (ZFP). This method estimate the evapotranspiration based on water content and soil suction. This method can also estimate the value of evaporation, evapotranspiration and ground water recharge. The data used in this study were obtained from a field experiment at Isfahan University of Technology. The experiment was factorial design [3×8] in the basic design of randomized complete blocks that the first factor was the types of mulch and the second factor was the depth of soil mulch. The field trial was conducted for 44 days. Results obtained from the ZFP model was compared with Ref-ET and OPTIWAT models. The experiment consisted of wood, sand and tire chips mulches with 2.5 and 5 cm thickness in the plots. Three plots were planted with grass and three plots left uncovered. The results showed that the depth of ZFP varied in different mulches. The highest ZFP depth was related to the uncovered plot and the lowest ZFP depth was related to the plot with 5 cm sand thickness. the results indicated that the experiment plot with no mulch had the greatest evapotranspiration (178 mm) and then woody chips mulch with a thickness of 5 cm, tire chips mulch with a thickness of 5 cm, tire chips mulch with a thickness of 2.5 cm, sandy mulch with a thickness of 2.5 cm, the woody chips mulch with a thickness of 2.5 cm and sandy mulch with a thickness of 5 cm, had more evapotranspiration, respectively. the results showed that the amount of evapotranspiration obtained by the ZFP model with the results of the Ref-ET and OPTIWAT model, were different. Ref-ET and OPTIWAT models under-estimated the actual evapotranspiration obtained by ZFP. In Ref-ET model, the equation of modified Blany-Cridle had the closest estimation (159 mm) to the evapotranspiration determined by ZFP model. In OPTIWAT model, the modified Jensen-Haise method had the nearest estimation (161.4 mm) to the ZFP model.

In arid and semi-arid regions, evaporation from the soil surface represents the major water balance component that causes losses of water. Urban landscape (particularly grass cover) consumes a large amount of water in urban areas. Using mulch is a proper method to reduce the cost and volume of irrigation. This field experiment was completely randomized blocks design with eight treatments and three replications. The experiment consisted of wood, sand and tire-chips mulches of 2.5 and 5 cm thickness. Three plots were planted with grass, three plots had no mulch or grass cover (control) and the remaining 18 plots were covered with mulches. In each plot, Chrysanthemum (Chrysanthemum Pompona) was planted and conducted during 70 days. Results indicated that the treatment with a thickness of 5 cm of sand mulch had the best performance on saving water. Then sandy mulch with a thickness of 2.5 cm, the tire-chips mulch with a thickness of 2.5 cm, wood-chips mulch with a thickness of 2.5 cm, the tire-chips mulch with a thickness of 5 cm and wood-chips mulch with a thickness of 5 cm had the best performance on reducing water consumption, respectively. The plots of grass and control consumed the greatest volume of water during the experimental period. Water consumption from the soil covered by woody chips mulch (5 cm) and sandy mulch (5 cm) decreased 50% and 87%, respectively compared to the grass cover. Also, the sand and woody chips mulch with a thickness of 5 cm decreased the water consumption volume, 26% and 78%, respectively compared to the control plot (no mulch).

1. Introduction: In conventional design of pile foundations, all loads are taken by the piles, i. e. the contact pressure between the raft and the soil is neglected. In the last decades, geotechnical engineers have started to take this pressure into account in design of pile foundation. Such a foundation, where the raft and the piles interact to transfer the loads to the ground, is in this dissertation called piled raft foundation or piled raft...

Some of the desirable properties of concrete include high impact resistance and great energy-sucking capacity to name a few. These properties can be improved through the use of sustainable materials. This study investigated the effects of partly replacing fine aggregate with linear low-density polyethylene (LLDPE) and waste rubber (WR) as fine aggregates on the efficiency of concrete under impact loading. Two water to binder ratio (W/B) percentages of (0.40 and 0.55) were selected, with six (LLDPE-R) replacement grades (0%, 5%, 10%, 15%, 20%, and 30%) and two silica fume (SF) replacement grades (0% and 15%). Six cylinders with 150 and 60 mm were subjected to an impact by a 4.45 kg hammer striking. Test results indicated that impact resistance for the first visible crack and the ultimate failure increased with LLDPE-R content, where it increased by 4.76 times. This study also demonstrated that the impact resistance for the first visible crack of LLDPE-R concrete was improved by an average of 295% for specimens without SF and 292% for specimens containing SF. This enhancement for the ultimate failure is 291% and 290% for specimens without SF and containing SF, respectively.

For improvement and stabilization of problematic soils in terms of geotechnical properties, it should be required to use proper materials. Therefore, tire chips is as new option can be suggested. On the other side, disposing of waste tire is one of the environmental problems. In present study, improving bearing capacity of kaolinite clay soil with using granule particle of tire waste (with aim of reducing environmental pollutants) based on laboratory tests have been investigated. Waste tire Granule particles in 1, 3 and 5 mm diameters and 2. 5, 5, 7. 5 and 10 percentage were mixed with clay. For evaluating geotechnical properties of stabilized clayey soil, compaction, uniaxial, direct shear and permeability tests were performed. Results of this study showed that, optimum of particle size and waste tire particle content are respectively 1 mm and 2. 5 percentage (by weight). So that, in this values minimum void ratio significantly decreased in improved specimens. Consequently, bearing capacity and compressibility were growth. Also, with adding waste tire granule particle by a size larger than 1 mm and more 2. 5 % content in improved soil, permeability went up.

As part of the stabilization systems for excavations and slopes, shotcrete today plays an extensive role in civil and mining engineering practices. A great number of efforts have been made during recent years to improve the strength and ductility of shotcretes. Fiber incorporation can be named as one of these efforts. Based on the type and characteristics of fibers, reinforced shotcretes display different properties. As a result, advantages and disadvantages of each type of fiber are being studied. This study presents the results obtained from experimental investigations of the influence of waste tire textile fiber addition on strength, ductility, and energy absorption capacity of shotcretes. After preparing specimens reinforced at fiber contents of 0. 5%, 1%, 1. 5%, and 2%, unconfined compressive strength, Brazilian tensile strength, and three-point bending strength were conducted on all samples. The results show that using the fibers inhibits the brittle behavior of specimens and increases energy absorption capacity. Several advantages of using this fiber can be named such as high entanglement in the matrix, low specific weight of the fibers as compared with mesh and steel fibers, easy pumping, and high durability in damp and acidic environments. Moreover, due to the fact of being waste materials, using these fibers leads to lowering the costs of projects as well as tackling the environmental hazards ensued by burying or burning them.