Evaluation on the performance of brick dust as a filler material for hot asphalt mix design in jimma zone

Abstract

Construction of highway pavement involves huge outlay of investment. A precise engineering design may save considerable investment; as well as reliable performance of the in-service highway can be achieved. Two things are of major considerations in this regard – pavement design and the mix design. This study emphasizes on the bituminous mix design considerations. A mix designer tries to achieve these requirements through a number of tests on the mix with varied proportions of material combinations and finalizes the best one. This often involves a balance between mutually conflicting parameters. A bituminous paving mixture is a mixture of coarse aggregate, fine aggregate and bitumen mixed in suitable proportion to result strong and durable mix with stand traffic load. In this paving mix, normally stone dust and cement are used as filler material. One of the main problem in the construction of bituminous paving mixture is the insufficiency amount of filler from crushing stone aggregate and cement supply is low. A study has been carried out in this research to explore the use of Brick dust as filler material for the bituminous mixture. From this point of view, the prime aim or main objective of this research is to evaluate the performance of brick dust as fillers in Hot Asphalt Mix design, according to the test procedure specified by ASTM. Several specimens of hot asphalt mixture were prepared according to ASTM D 1559 using aggregate blend with brick filler and aggregate blend without brick filler. The aggregate blend made by using Job mix formula to obtain the percentage of mix material, for aggregate blend without brick G-1 32%, G-2 23% and G-3 45% for Aggregate blend with brick filler G-1 30%, G-2 18%, G-3 45% and G-4 7%; where G-1 Coarse Aggregate 3/4, G-2 Coarse Aggregate 3/8, G-3 Fine Aggregate, and G-4 brick filler. The result of Marshall test on mix design of hot asphalt mixtures, for the wearing coarse were conclude that, the hot asphalt mixes with these brick fillers result in satisfactory Marshall Properties when compared with bituminous mixes not blend with brick filler, with its optimum asphalt content of 5.1% and 5.4% (by weight of total aggregate) respectively, the Specimens with blend with brick filler lead to produce asphalt mixture with higher Marshall stability, lower flow, lower void filled by asphalt and lower void in total mix comparing with specimens not blend with brick filler. Hence, brick dust can totally replace stone dust and cement filler in bituminous paving mix, so it is recommended to use brick dust as filler material in bituminous paving mix, it may save considerable investment; as well as reliable performance of the in-service highway can be achieved.