Effect of Adding Steel Filings Aggregates on The Properties of Hot Mix Asphalt

Abstract

Hot Mix Asphalt (HMA), which are used in road's courses and flexible pavement structures, consisting of fine and coarse aggregates, filler, and binder(asphalt) ,mixed together in percent's according to a specific specifications. The main objective of this study is to investigate experimentally the effect of adding Steel Filing Aggregate (SFA) on the properties of Hot Mixtures Asphalt for surface layers. Steel filing Aggregate is a product of filing, drilling, and cutting of steel industry which, can be used as a partial replacement for fine aggregate in the creating Hot Asphalt Mixtures, for economical , environmental, and improvement purposes. The proposed mix designs specimens test of HMA for surface layer were prepared using : obtained Optimum Asphalt Content (OAC) (where the asphalt of penetration grade 40 was provided from Begi Oil Refinery, which was determined to be equaled 5.07 % (of the total weight mix) , ordinary portland cement as the mineral filler by 5 % (of the total weight of aggregates) and locally aggregates, and then tested according to Marshall test method (ASTMD1559&MS-2). Steel Filling Aggregates (SFA), which were passing through the sieve No.4 (4.75 mm) were added to the above HMA samples in three different percentages which were 5 % , 10 % and 20 % (of the total weight of mix) in order to evaluate their effects on some of the Marshall test properties of HMA . The experimental results and calculations for Marshall Tests on mix designs specimens test of HMA showed that adding SFA by above percentages on HMA, satisfy the requirements of the Iraqi General Specification for Roads & Bridges (SORB/2003) and has given significant improvement .The results also showed that 10% of SFA (of the total weight of mix) is the optimum percent .