Experimental study on porous asphalt design

Transportation sector has an important role in the recent developments. Increasing living standards due to technological and economic developments also affect the transportation sector. This situation plays an important role especially in the increase of vehicles' number in our country. The increase in the number of vehicles increases the value of pavement in the highway construction sector. Generally, the construction of hot mix asphalt and chip seal pavements are more applied in our country. However, the application of these pavements may cause different problems in some area. Bituminous hot mix asphalt, especially in the city and parking areas, causes the accumulation of water on the pavement surface after raining due to the insufficient drainage systems. These accumulated water on the road surface make the movement of vehicles and pedestrians difficult. At the same time, existing of water on the road surface decreases the skid resistance of the pavement surface and it may increase the risk of accidents. In this experimental study, porous asphalt designed as an alternative pavement to solve the problems caused by various traffic volumes. Porous asphalt is a type of permeable pavement structure which designed with 20-28% air voids content. Porous asphalt pavements prevent the flow water on the road surface due to its permeability property. At the same time, the noises caused by the different type of vehicles in the city may be minimized due to the more air voids content of porous asphalt. In this thesis, sub-base, base and wearing course of porous asphalt designed separately in the laboratory temperature. The performance of limestone used in the designing of porous asphalt was determined by the conducting of Los Angeles, specific gravity, water absorption, flakiness index, resistance to air effects and Methylene blue tests. Sub-base layer was designed as the same method which is used in the sub-base of hot mix asphalts according to the Turkish Highway Construction Standard, while base layer consists of a porous concrete layer designed with cement and uniform aggregate gradation in order to have a permeable structure. Finally, Wearing course was designed according to the Turkish Highway Construction Standard. In addition, 50/70 penetration bitumen was used in the wearing course design. Various experimental tests such as Marshall stability, Cantabro, softening point and bitumen infiltration tests were conducted and obtained results compared with the Turkish Highway Construction Standard and literatures limits. Moreover, Permeability and air voids content of base and course layers of porous asphalt were also evaluated in the laboratory.