Shear modulus and damping ratio of sand-granulated rubber mixtures
来源期刊:中南大学学报(英文版)2015年第8期
论文作者:M. Ehsani N. Shariatmadari S. M. Mirhosseini
文章页码:3159 - 3167
Key words:sand-rubber mixture; shear modulus; damping ratio; low to high shear strain amplitude; cyclic triaxial test; torsional resonant column test; granular rubber
Abstract: Recycled waste tires when mixed with soil can play an important role as lightweight materials in retaining walls and embankments, machine foundations and railroad track beds in seismic zones. Having high damping characteristic, rubbers can be used as either soil alternative or mixed with soil to reduce vibration when seismic loads are of great concern. Therefore, the objective of this work was to evaluate the dynamic properties of such mixtures prior to practical applications. To this reason, torsional resonant column and dynamic triaxial experiments were carried out and the effect of the important parameters like rubber content and ratio of mean grain size of rubber solids versus soil solids (D50,r/D50,s) on dynamic response of mixtures in a range of low to high shearing strain amplitude from about 4×10-4% to 2.7% were investigated. Considering engineering applications, specimens were prepared almost at the maximum dry density and optimum moisture content to model a mixture layer above the ground water table and in low precipitation region. The results show that tire inclusion significantly reduces the shear modulus and increases the damping ratio of the mixtures. Also decrease in D50,r/D50,s causes the mixture to exhibit more rubber-like behavior. Finally, normalized shear modulus versus shearing strain amplitude curve was proposed for engineering practice.
M. Ehsani1, N. Shariatmadari1, S. M. Mirhosseini2
(1. School of Civil Engineering, Iran University of Science and Technology, Tehran, Iran;
2. Department of Civil Engineering, Amirkabir University of Technology, Tehran, Iran)
Abstract:Recycled waste tires when mixed with soil can play an important role as lightweight materials in retaining walls and embankments, machine foundations and railroad track beds in seismic zones. Having high damping characteristic, rubbers can be used as either soil alternative or mixed with soil to reduce vibration when seismic loads are of great concern. Therefore, the objective of this work was to evaluate the dynamic properties of such mixtures prior to practical applications. To this reason, torsional resonant column and dynamic triaxial experiments were carried out and the effect of the important parameters like rubber content and ratio of mean grain size of rubber solids versus soil solids (D50,r/D50,s) on dynamic response of mixtures in a range of low to high shearing strain amplitude from about 4×10-4% to 2.7% were investigated. Considering engineering applications, specimens were prepared almost at the maximum dry density and optimum moisture content to model a mixture layer above the ground water table and in low precipitation region. The results show that tire inclusion significantly reduces the shear modulus and increases the damping ratio of the mixtures. Also decrease in D50,r/D50,s causes the mixture to exhibit more rubber-like behavior. Finally, normalized shear modulus versus shearing strain amplitude curve was proposed for engineering practice.
Key words:sand-rubber mixture; shear modulus; damping ratio; low to high shear strain amplitude; cyclic triaxial test; torsional resonant column test; granular rubber