Interface treatment of longitudinal joints for porous asphalt pavement

In Germany, multiple lanes of porous asphalt (PA) road surfaces should be constructed with a longitudinal hot joint construction over the full pavement width according to the 'Technical Instruction for Porous Asphalt Surfacing'. In this way, longitudinal cold joints are avoided and the transverse drainage is not impeded. Therefore, the construction of PA always requires the closure of all lanes in one direction of traffic. However, such measures are only possible in exceptional cases with heavily loaded road sections on motorways with 6-8 lanes. In this research, different variants of joint construction methods for PA were realised in practice. The performance of each variant was investigated with respect to the tensile strength, the tensile strain at break, the permeability and the resistance against ravelling of the joint. After comparing the different construction methods for longitudinal joints, three of them proved to be able to ensure both the structural durability and the water permeability in the joint area.