Asphalt Concrete Mixtures with Coal Bottom Ash as Fine Aggregate Substitution and Crumb Rubber as Asphalt Substitution

Abstract

This research conducting the substitution of coal bottom ash and crumb rubber in asphalt concrete wearing course (AC-WC) mixtures. The objective is to help reduce waste materials and obtaining Marshall parameters that meet the requirements for asphalt mixtures. The percentage variations used for the substitution were 6%, 9%, and 12% coal bottom ash and 5%, 8%, and 11% crumb rubber. In Marshall test used varies asphalt content, the optimum asphalt contents (OAC) obtained were 5.85%, 6.03%, and 6.2%. Then, the OAC was used in asphalt concrete mixtures with coal bottom ash as fine aggregate substitution. The best results were obtained at the combination of 6% coal bottom ash and 5.85% asphalt content. Consequently, the combination was used in the mixtures by adding crumb rubber as the substitution of the asphalt. The results shows that the Marshall parameters obtained by all percentages of crumb rubber substitution have fulfilled the requirements with the highest stability of 1928.16 kg. The durability test on asphalt concrete mixtures with 6% coal bottom ash as fine aggregate substitution and 11% crumb rubber as asphalt substitution with 5.85% asphalt content obtained 92.82%, so that the requirement of ≥90% of the Bina Marga 2018 Specifications Revision 2 (2020) have been fulfilled.