Durability Evaluation Of Easy Compaction And High-Durability Ultra-Thin Overlay

As one of the most popular preventive maintenance of road surface, the ultra-thin overlay with good durability and surface function could provide better conditions for the safe and smooth running of vehicles. The objective of this study is to prepare an ultra-thin overlay with easy compaction and high-durability (ECHD) and to evaluate its durability. First, the optimal dosage of the easy compaction modifier was determined based on the grey theory. Then, matrix asphalt and SBS-modified asphalt mixtures were used as control groups. Through an experimental design, the ease of compaction, fatigue durability, ageing resistance, surface function durability, and interlayer durability of the three asphalt mixtures were compared. Finally, using the test road, a field effect evaluation of the durability of the ECHD ultra-thin overlay was performed, and a durability evaluation system for ultra-thin overlays was established. The results showed that the optimal content of the modifier was 6%. The ECHD asphalt mixture exhibited the smallest Compaction energy index (CEI), largest compaction rate (K), and easiest compaction. The splitting strength ratio was used as the ageing coefficient to evaluate the ageing performance. Compared with the matrix asphalt and SBS-modified asphalt mixture, the ECHD asphalt mixture exhibited better ageing durability and fatigue durability. Moreover, after 30,000 wear times, the mass loss rate of ECHD ultra-thin overlay was 0.4%, the texture depth and pendulum value decreased by 25% and 16%, and the shear strength and pull-off strength decreased by 6% and 20% respectively, which showed that it had the best performance in wear-resistance, skid-resistance, water-impermeable and interlayer durability. In addition, the durability effect of the ECHD ultra-thin overlay test road was evaluated and a durability evaluation system of the ECHD ultra-thin overlay was proposed, which can act as a reference for the durability evaluation of the same type of overlays.