Effect of Using a 50:50 Blend of Recycled Concrete (R.C.C) Waste Dust and Brick Masonry Waste Combined as Filler in Bituminous Mix Design

Abstract: Bituminous concrete, often referred to as asphaltic concrete, is one of the most technically refined and high-cost types of flexible pavement layers employed in surface courses. Due to its premium performance requirements, bituminous mixtures are precisely formulated to meet specific standards for strength, stability, and durability. This composition includes well-graded coarse aggregates, fine aggregates, and a mineral filler, all uniformly coated with a bitumen binder. The mineral filler, which passes through a 0.075 mm sieve, plays a crucial role in enhancing the performance of asphalt mixtures. Research shows that Marshall Stability improves with an increase in filler content, and the Asphalt Institute recommends 4 to 8% filler content in asphalt concrete. In Bangladesh, traditional fillers like cement, limestone, and granite powder are neither economically viable nor widely available. As an alternative, this study investigates the use of a 50:50 blend of recycled concrete (R.C.C) waste dust and brick masonry waste combined with natural sand as a cost-effective and sustainable filler. The study evaluates the performance characteristics of bituminous mixtures incorporating this blended filler and compares the results with those of mixes using conventional filler materials such as fine sand and stone dust. The Marshall mix design procedure was utilized to assess the strength and workability of the mixes. The Marshall Stability values obtained for mixtures using fine sand with stone dust and the blended filler (50:50 blend of recycled concrete (R.C.C) waste dust and brick masonry waste) were both of them 2.15 kN respectively, all surpassing the minimum requirement as outlined in the Marshall Design criteria. These findings suggest that the use of recycled R.C.C and brick masonry waste in combination with sand can serve as a promising and economical filler alternative in asphaltic concrete.