Reduce Tire-Pavement Noise by Porous Concrete Pavement

This study investigates the effect of Portland cement porous concrete on tire-pavement noise reduction. The acoustical absorption coefficients were measured in the laboratory for porous concrete materials representing combinations of various maximum aggregate sizes, gradation, layer thickness and composition layers. The laboratory results indicated that the porous concrete with a maximum aggregate size of 9.5mm had the highest acoustical absorption coefficient. It also showed that the peak absorption coefficient not only depends on the mixture characteristics, but also on the thickness of the specimen. A thickness of 80mm was found to have optimum absorption. The findings from the laboratory study were used to design and build a field test road with two test cells. The "wet on wet" construction method was successfully used to build the porous cement friction course over the conventional concrete pavement. Tire-pavement noise was measured on the test cells using the close proximity method under various vehicle speeds and different tire treads. Tire-pavement noise was also measured for other pavement textures to quantify the noise reduction effect of the porous cement concrete pavement. The field measured tire-pavement noise clearly showed that the porous cement concrete can significantly reduce the tire-pavement generated noise by 4 to 8 dB.