Design and Text Method of Indoor Noise for Micro-Surfacing Mixture

Micro-surfacing mixture has been widely used in pavement maintenance due to its several advantages, including water proofing, anti-skidding, and wear resistance. However, micro-surfacing pavement produces more noise than common pavement. It is difficult to measure this kind of noise with existing indoor test practices. A mineral aggregate gradation of low-noise micro-surfacing was proposed along with a novel test method. The addition of fiber was useful for decreasing the aggregate size and reducing the noise produced. The brush test for emulsified asphalt cold recycling mixture was used to measure the indoor noise of the micro-surfacing mixture, and micro-surfacing mixtures with different levels of gradation were tested. Results showed that the indoor noise is related to both speed and aggregate size, and noise is reduced by the addition of fiber and decreased structural depth. The indoor noise was reduced by increasing the sieve size to 7.2 mm pores and increasing the amount of fine aggregate.