A Comprehensive Review on the Properties of Coal Bottom Ash in Concrete as Sound Absorption MaterialNurul Izzati Raihan Ramzi Hannan, Shahiron Shahidan, Noorwirdawati Ali and Mohamad Zulkhairi MaarofMATEC Web Conf., 103 (2017) 01005DOI: https://doi.org/10.1051/matecconf/201710301005