Dynamic shear modulus and damping ratio of recycled concrete aggregate—recycled tire waste mixture using resonant column apparatus

Abstract

The accumulation of waste tires is a global problem related to natural resources and the environment. The storage or burning of tires causes toxic chemicals to seep into the surrounding environment, which poses a serious ecological threat. Many previous studies have shown that waste tires can be used in geotechnical engineering. It was found that rubber reinforcement can increase the plasticity of sandy soil and improve its shear strength. It can control pore water pressure accumulation and improve dynamic properties. For cohesive soils, rubber additives can reduce dry density and improve compressive strength and soil stability. When mixed with soil with optimum content, waste tires can reduce various adverse effects of waste tire accumulation on the environment. The application of rubber has also a good impact on environmental protection and the promotion of “green design”. This paper presents the dynamic properties (shear modulus and damping ratio) of the RCARTW mixture for small, medium, and large ranges of shear strain levels (from about 1.510-4% to 1.310-2%). All specimens are constructed using different percentages of granulated tire rubber and concrete aggregate from curb crushing. A series of laboratory tests, resonant, and damping, are performed in the resonant column apparatus. The maximum shear modulus and minimum damping ratio are presented with the percentage of granulated rubber. The normalization is also applied to the Gmodulus and Dratio data set. Furthermore, a comparison is made between the results obtained for the tested geocomposites and a mixture of pure RCA.

Keywords

• dynamic loading
• small strains
• non-destructive laboratory testing
• recycled materials