Damping properties of sand-rubber mixtures
Tay, Clara Hui Xia
Date of Issue2017-05-11
School of Civil and Environmental Engineering
Vast amount of waste rubber tyres that are disposed at the landfill can be recycled for greater purposes. Rubber with its high damping characteristic can be used with soil to reduce vibrations when exposed to seismic loadings. Hence, the objective of this project is to determine the damping properties of sand-rubber mixtures. To achieve the objective, modified triaxial cell with bender elements was used to investigate the effect of the size of the rubber tyre chips, mix proportions of the sand-rubber mixtures and confining pressures on the damping properties of sand-rubber mixtures. Compression (P) and shear (S) wave signals were obtained at different frequencies: 10, 20 and 50 kHz for P-waves and 3, 5, 10, 20 kHz for S-waves. Samples were subjected to confining pressures of 50, 100, 200 and 400 kPa. Wave signals were then processed using MATLAB to determine the damping ratio using the Hilbert transform method. Results showed that small-strain shear modulus decreases with increasing rubber content and increases with increasing confining pressure. Damping ratio increases with increasing rubber content and decreases with increasing confining pressure. Damping ratio is higher for sand-coarse rubber mixtures indicating that larger rubber tyre chips are more effective in damping.
Final Year Project (FYP)
Nanyang Technological University