Evaluation of the use of steel slag and pyrophyllite materials in the porous asphaltmix

The rapid populationgrowth in some urban areas has causedmajor changes in land use, in which many productive agricultural landshave been converted into residentialor business. These conditions have reduced the land's ability to absorb and be infiltrated by rainwater particularly during rainy season, resulting flooding and decrease of groundwater. The purpose of this study was to develop the optimum porous asphalt mixture design, which should provide a satisfactory level of load carrying capacity and permeability capability. To achieve the objective, four scenarios of asphalt porous mix designs were conducted using: (a) standard material combined with pyrophyllite, (b) standard material combined with steel slag, (c) varied gradations of standard materials. A total of 60 specimens per scenario (180 total of specimens) wereprepared in accordance with the Marshall Test procedures. Each sample is then tested to evaluate its permeabilitycapability andits Marshall characteristics performance. The test results showed that: (a) all mix scenarios had a good permeability and Marshall performance but the stability, in which no sampleperformed above 500 kg, (b) the optimum aggregate proportion to result in a good performance is 65% - 35% both for pyrophyllite and steel slag mixes, (c) samples with steel slag has the highest stability and (d) mixture with AAPA specification resulted as the best performing. Reviewing the test results further studies are needed in the following areas: (a) the use of asphalt additive to improve the performance of asphalt porous and (b) investigate the chemical reaction between steel slag asphalt mixture.