Experimental investigation of sound transmission loss in concrete containing recycled rubber crumbs

This study represents procedures and material to improve sound transmission loss through concrete without having any significant effects on mechanical properties. To prevent noise pollution damaging effects, and for reducing the transmission of the noises from streets to residential buildings, sound absorbing materials could be effectively produced. For this purpose, a number of several mixture designs have been investigated in this study to reduce the sound transmission through concrete, including control sample and three mixtures with recycled rubber with sizes of from 1mm up to 3 mm to limit the sound transmission. The rubber is used as a replacement of 5, 10, and 15 percent of sand aggregates. First, 7, 14 and 28-day strengths of the concrete have been measured. Subsequently, the sound transmission losses through the samples have been measured at the range of 63 Hz up to 6300 Hz by using impedance tube and the transfer function. The results show specimens containing 15% fine-grained crumbs, the loss of sound transmission were up to 190%, and for samples with 15% coarse-grained rubber, the loss of sound transmission were up to 228%, respectively. It is shown that concrete with recycled rubber crumbs could effectively improve environmental noise absorption.