Determining of the fatigue resistance of a grid-reinforced asphalt concrete by using four point bending beam test

Abstract

Flexible pavement structures are prone to cracking due to the fatigue and thermal influence, while a significant problem presents the appearance of reflective cracking in semi-rigid pavement structures or in rigid pavements overlaid with asphalt concrete. Reinforcement of asphalt concrete by using geogrids substantially slow down, if not stop crack propagation. The paper presents the results of an experimental study aimed at determining the influence of geogrid application on the fatigue resistance of asphalt concrete. Two double layered sets of specimens, with and without a grid, were tested (reinforced and unreinforced). Testing beams were cut from the slabs prepared by a non-standard method, using a one-ton roller. The thickness of the bottom layer of asphalt beams was 20 mm, the thickness of the upper layer was 30 mm, the width was 60 mm and the length 400 mm. Reinforced samples contained a high-strength adhesive geosynthetic grid between layers. The testing of fatigue resistance of asphalt mixtures was carried out by application of the four-point bending beam test, while two failure criteria were used to analyze the testing results. Presented research helped to quantify the extension of fatigue life that can be obtained by reinforcement, depending on the fatigue criteria.