Evaluation of the Shear Strength Behavior of TDA Mixed with Fine and Coarse Aggregates for Backfilling around Buried Structures

Abstract

Although some discarded tires are reused in various applications, a considerable number end up in landfills, where they pose diverse environmental problems. Waste tires that are shredded to produce tire-derived aggregates (TDA) can be reused in geotechnical engineering applications. Many studies have already been conducted to examine the behavior of pure TDA and soil-TDA mixtures. However, few studies have investigated the behavior of larger TDA particles, 20 to 75 mm in size, mixed with various types of soil at percentages ranging from 0% to 100%. In this study, TDA was mixed with gravelly, sandy, and clayey soils to determine the optimum soil-TDA mixtures for each soil type. A large-scale direct shear box (305 mm × 305 mm × 220 mm) was used, and the mixtures were examined with a series of direct shear tests at confining pressures of 50.1, 98.8, and 196.4 kPa. The test results indicated that the addition of TDA to the considered soils significantly reduces the dry unit weight, making the mixtures attractive for applications requiring lightweight fill materials. It was found that adding TDA to gravel decreases the shear resistance for all considered TDA contents. On the contrary, adding up to 10% TDA by weight to the sandy or clayey soils was found to increase the shear resistance of the mixtures. Adding up to 10% TDA by weight to the clayey soil also sharply increased the angle of internal friction from 18.8° to 32.3°. Moreover, it was also found that the addition of 25% TDA by weight to the gravelly or sandy soils can reduce the lateral earth pressure on buried structures by up to 20%. In comparison, adding 10% TDA to clay resulted in a 36% reduction in the lateral earth pressure.

Evaluation of shear strength parameters of sustainable utilization of scrap tires derived geo-materials for civil engineering applications

“…The ANN and GMDH models have R-values of 0.9977 or 0.9994, respectively, for ANN models and 0.9862 or 0.9990 for GMDH models. Mathematical formulae for implementing the GMDH models are considered relatively easy (El Naggar and Iranikhah, 2021).…”

Lightweight and Alternative Backfills for Highway Applications: State-of-the-Art Practice in the U.S.A.

“…Type B is a larger size produced by a shearing process, and is suitable for embankment fill, wall backfill, and landfill drainage. The effect of the percentage of TDA in aggregate mixes was investigated by El Naggar and Iranikhah ( 28 ). The optimum TDA percentage that maximizes shear strength is 0% to 10% for gravel mixes.…”

Properties and Behavior of Rubberized Concrete Enhanced with PVA Fibers

“…A promising way to recycle scrap tires is to use them in civil engineering applications. For example, tire-derived aggregate (TDA), made from shredded scrap tires, has been used for many years in applications such as vibration control, lightweight embankment fill, backfill behind retaining walls, backfill above and around buried pipes and culverts, fill beneath shallow foundations, and as landfill drainage layers [6][7][8][9][10][11][12][13][14][15][16][17][18]. Another promising approach is to incorporate TDAs in concrete to produce lightweight concretes with special properties [19][20][21][22].…”