Determining the performance of semi-flexible pavements designed with different porous asphalt gradations

The road network is developing day after day and the demand for highways is augmenting in consequence of the world population. Flexible and rigid pavements are generally used as road pavement. Semi-flexible pavement has been produced by researchers as a new design which combines the advantages of both rigid and flexible pavements. This type of pavement has been opened to traffic in a shorter time than the rigid pavement. In addition, it is both more durable and long-lasting than the flexible pavement. Semi-flexible pavement (SFP) is generally used at road junctions, airport aprons and heavy loading areas. SFP is formed with flowable cement mortar which is poured into a porous asphalt (PA) mixture with an air void of 25-35%. In this thesis, a PA design with 3 different gradations has been prepared, and after the fluid cement mortar has been injected into the designs meeting the optimum performance criteria, the SFP with the highest performance has been selected. The optimum bitumen ratio for PA has been specified depending on the physical properties of the aggregates. Fibre has been used as an additive in the PA mixture. In order to determine the performance of PA mixtures, bitumen drain down, Marshall stability and indirect tensile strength ratio tests have been carried out. Marshall stability, indirect tensile strength ratio, compressive strength, Cantabro, freeze-thaw, permeability and skid resistance tests have been performed to determine the prepared SFP samples in the curing periods of 1,3,7 and 28 days. Accordingly, the performance of SFP samples prepared with the PA-2 mixture design has been found as the optimal design.