Investigation of porous asphalt mixtures prepared with different modifying additives

Safe and quick discharge of the water from the road surface has always been the most important problem regarding the traffic safety on the highways, where intense precipitation is observed. The water pools that occur on the road surface during heavy rains can easily lead to accidents by means of the disconnection of wheels with the road surface causing the driver to lose steering ability. For the asphalt concrete and stone mastic asphalt wearing courses which form the uppermost level of the hot bituminous mixtures, rain water is discharged from the surface by means of the longitudinal/horizontal slopes. However, in locations where heavy rains are observed, such slopes fail to be sufficient to discharge the rainwater. Due to the high void content of the porous asphalt, the inflowing surface water is discharged through the pavement by means of the longitudinal / horizontal slopes. Apart from all these, it provides substantial absorption of the frictional noise caused by the contact between the road surface and the wheels by reducing noise wise problems. It improves the strength against shear due to its gap gradation. In this study, the performances of the porous asphalt mixtures prepared by different modified bitumenes in means of applicability under different climatic and traffic conditions are investigated. For this purpose, a Porous Asphalt Mix Design has been prepared using Marshall Design methodology with basalt aggregate of Yapracık rock quarry, Ankara. The modified bitumen prepared by using MD243 SBS (Styrene-Butadiene-Styrene) and TPS (TafPack?Super) additives from Kırıkkale 50/70 bitumen, were tested binder wise in accordance with the technical specification for modified bitumen. The porous asphalt mixtures prepared with the addition of MD243 SBS and TPS additives at a proportion of 7,5 % and 14 % respectively, were tested in means of rutting, indirect tensile strength, permeability, bitumen drain down, cantabro, stripping, fatigue tests and their performance has been examined using the data obtained during the tests.