ABSTRACT
Geosynthetic reinforcement of asphalt layers has been used for several decades. Evaluation of the influence of these materials on pavement fatigue life is still ongoing, especially for new types of geocomposites. This paper presents the evaluation of fatigue performance of large asphalt concrete beams reinforced with a new type of composite in which square or hexagonal polypropylene stiff monolithic paving grid with integral junctions is bonded to polypropylene non-woven paving fabric. Unreinforced samples were used as reference. Fatigue testing was performed in the scheme of four-point bending test (4PB-PR) in the controlled strain mode at +13°C. Test results were analysed in several aspects, including the standardised approach based on stiffness reduction, but also using critical strain at one million cycles. A new parameter – relative increase in fatigue life – was introduced in the analysis as well. On the basis of the obtained results, it can be concluded that the evaluated composites will have evident positive effect on pavement performance and may contribute to a several fold increase in fatigue life of pavement structure. More benefits in terms of pavement bearing capacity are expected in the case of reinforcement of thick and new asphalt pavements. The use of hexagonal geogrid resulted in greater improvement of fatigue resistance than composites with square geogrid.
