Experimental investigation of scrap-tire crumb rubber application in noise-suppression structures

Abstract

Experimental investigations into acoustic properties of building materials and structures manufactured thereof were conducted in a noise-suppression chamber. A study was made of the noise-suppression efficiency of scrap-tires of different crumb rubber, using the source of constant noise from loudspeakers “Bruel&Kjaer”. For experiments, crumb rubber of 3 different sizes was used: crumb rubber I with the size of 0.5–1 mm, II – 4 mm, and III – 6 mm. Scrap-tire crumb rubber was placed into the samples of experimental structures of different thickness (50 mm, 100 mm, 150 mm and 200 mm). The experimental investigation results show that the coarsest crumb rubber (6 mm) is most efficient in suppressing low-frequency sounds (up to 300 Hz), when noise level reduction gets changed in the range of 31–35 dB, depending on the samples of the experimental structure. High-frequency sounds (over 800 Hz) are most efficiently suppressed by the finest scrap-tire crumb rubber (0.5–1 mm), noise level reduction changes from 53 dB to 64 dB.