The Impact of Utilizing Silica Fume as a Filler on Asphalt Concrete Mixes

Abstract

This study evaluates the influence of utilizing silica fume as a stabilizer to the filler on the behavior of asphalt mixes. The investigation of the properties of asphalt mixes was conducted by using different percentages of Silica Fume (0, 3, 6, and 9% by filler weight). Results indicate that, the OAC is 4.7% and it achieves the best results in the Marshall tests. Marshall Stability is increased by about 27.5% and the flow is decreased by about 20.2 %. In this study the implementation of 9% of silica fume in the asphalt concrete mix showed a considerable excess in the resistance to moisture damage of 28% when compared to the original mix. A great decrease in the tensile strength of asphalt concrete mixes, in a range from (4-15)% could be noticed following the moisture damage process for both the reference and silica fume adjusted mixes. Six percent of it was the optimum percent that had developed the tensile characteristics of the hot asphalt concrete mixes. The moisture sensibility of the asphalt concrete was reduced with an increase in the silica fume content. Following the moisture damage process, Silica fume of 9% was the optimum percent that had developed the punching shear characteristics of asphalt concrete. It exhibited a positive effect of 20%, while 6-9% of silica fume exhibited a positive effect of 5-9% on the development of the tensile characteristics of asphalt concrete.