Experimental Investigation of Applicability of Sand Tire Chip Mixtures as Retaining Wall Backfill
17 Mar 2015-pp 1420-1429
TL;DR: In this paper, the behavior of a cantilever retaining wall (CRW) backfilled with light weight fill material through small scale model wall tests was explained. But the model wall was installed in a Perspex container, tested under static and seismic loading conditions.
Abstract: This paper explains the behavior of a cantilever retaining wall (CRW) backfilled with light weight fill material through small scale model wall tests. CRW model of height 60 cm and base width 50 cm was built with hollow aluminum sections. The model wall was installed in a Perspex container, tested under static and seismic loading conditions. Waste tire chips of 1 cm square cross section and 20 mm length mixed with the cohesionless sand in 5%, 10%, and 15% by weight were used as light weight backfill material. Concrete cubes were used as surcharge loading on the backfill during static testing. The lateral wall movements along the height of the wall were monitored during tests using displacement transformers. 1g shaking table tests have been conducted on the selective models to check the behavior of the cantilever wall under seismic loading conditions. It has been observed that the inclusion of tire chips in the backfill soil has led to the reduction of lateral wall movements due to the lesser unit weight of the mixtures. The reduction in the acceleration of the backfill was also observed during seismic testing in sand-tire chip (S-TC) backfill compared to the controlled case (only sand).
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TL;DR: In this article, a triaxial testing program was conducted to investigate the stress-strain relationship and strength of tire chips and a mixture of sand and tire chips, and the test results and additional information from the literature were used in the numerical modeling of wall backfills, both unreinforced and reinforced with geosynthetics.
Abstract: The growing interest in utilizing waste materials in civil engineering applications has opened the possibility of constructing reinforced soil structures with unconventional backfills. Scrap tires are a high-profile waste material for which several uses have been studied, including the use of shredded tires as backfill. A triaxial testing program was conducted to investigate the stress-strain relationship and strength of tire chips and a mixture of sand and tire chips. The test results and additional information from the literature were used in the numerical modeling of wall backfills, both unreinforced and reinforced with geosynthetics. The numerical modeling results suggest tire shreds, particularly when mixed with sand, may be effectively used as backfill.
333 citations
"Experimental Investigation of Appli..." refers background in this paper
...The sand tire chip mixtures contract initially on triaxial testing and then dilates but the amount of dilation is much less than that of dense sand (Lee et al. 1999)....
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TL;DR: In this paper, the feasibility of using shredded waste tires to reinforce sand was investigated, and three significant factors affecting shear strength were identified: normal stress, shred content, and sand matrix unit weight.
Abstract: The objective of this study was to investigate the feasibility of using shredded waste tires to reinforce sand. Direct shear tests were conducted on mixtures of dry sand and shredded waste tires. The following factors were studied to evaluate their influence on shear strength: normal stress, sand matrix unit weight, shred content, shred length, and shred orientation. From results of the tests, three significant factors affecting shear strength were identified: normal stress, shred content, and sand matrix unit weight. A model for estimating the strength of reinforced soils was also evaluated to determine its applicability to mixtures of sand and tire shreds. When the model is calibrated using results from one shred content, it may be useful for estimating the friction angle for other shred contents. In all cases, adding shredded tires increased the shear strength of sand, with an apparent friction angle (ϕ′) as large as 67° being obtained. Shred content and sand matrix unit weight were the most significan...
324 citations
TL;DR: In this paper, the use of shredded scrap tires as a lightweight fill material in highway construction is discussed and design parameters for embankments constructed using discarded shredded tires are presented based on laboratory model studies, numerical analyses, and field performance of test fills.
Abstract: This paper describes research undertaken to develop design procedures for using shredded scrap tires as a lightweight fill material in highway construction. The benefits of using scrap tires are particularly enhanced if they can be used to replace virgin construction materials made from nonrenewable resources. This paper addresses the use of tire chips as a highway embankment material. Design parameters for embankments constructed using discarded shredded tires are presented based on laboratory model studies, numerical analyses, and field performance of test fills. The conclusions of this report support the use of tire chips as an environmentally acceptable lightweight fill in highway applications if properly confined. Recommendations for design procedures and construction specifications for the use of tire chips in highway fills are provided.
255 citations
TL;DR: In this article, the authors demonstrated that sand-tyre chip mixtures up to 20% could be a potential material for highway construction and embankment construction up to around 10 m height.
Abstract: Scrap tyres can be shredded into chips and can easily be mixed with granular soils. To assess the behaviour of the admixtures, compressibility and triaxial compression tests were carried out by varying chip size and chip content. The results demonstrated that sand–tyre chip mixtures up to 20% could be a potential material for highway construction and embankment construction up to around 10 m height.
156 citations
Journal Article•
TL;DR: In this article, the engineering properties needed to put tire chips into use are presented, including gradation, specific gravity, compacted density, shear strength, compressibility, and coefficient of lateral earth pressure at rest.
Abstract: Scrap tires that have been cut into chips are coarse grained, free draining, and have a low compacted density, thus offering significant advantages for use as lightweight fill and retaining wall backfill. The engineering properties needed to put tire chips into use are presented. The properties determined for tire chips, from three suppliers, are gradation, specific gravity, compacted density, shear strength, compressibility, and coefficient of lateral earth pressure at rest. The 76-mm (3-in.) maximum size and high compressibility of the tire chips necessitated design and fabrication of custom-made testing equipment. The tests showed that the tire chips are composed of uniformly graded, gravel-sized particles that absorb only a small amount of water. Their compacted density is 0.618 to 0.642 Mg/cu m (38.6 to 40.1 pcf), which is about one-third that of compacted soils. The shear strength was measured in a large-scale direct shear apparatus. The friction angle and cohesion intercept ranged from 19 to 25 degrees and 8 to 11 kPa (160 to 240 psf), respectively. The compressibility tests showed that tire chips are highly compressible on initial loading, but that the compressibility on subsequent unloading and reloading cycles is less. The horizontal stress was measured during these tests and showed that the coefficient of lateral earth pressure at rest varied from 0.26 for tire chips with a large amount of steel belt exposed at the cut edges to 0.47 for tire chips composed entirely of glass-belted tires.
137 citations