Laboratory investigation into the crack propagation mechanism of geosynthetic reinforced asphalt concrete using digital image correlation technique

Geosynthetic reinforcement has proven effective in mitigating reflective cracking in new pavement overlays. This study aimed to compare the ability of five different geosynthetic reinforcement products to alleviate cracking in overlays. Each product was sandwiched within a two-layered asphalt concrete (AC) beam specimen and subjected to a four-point notched beam fatigue test. The study monitored crack propagation, understood crack propagation mechanisms, and quantified crack lengths in different geosynthetic-reinforced AC beam specimens during a notched beam fatigue test using the digital image correlation (DIC) technique. The DIC analysis generated full-field displacement and strain contours, depicting the damage mechanisms of geosynthetic reinforcement products in AC overlays under fatigue loading. The quantitative analysis measured the cracked areas caused by each product. The interfacial damage observed in various geosynthetic-reinforced beam specimens under different test conditions suggested that the failure modes of AC beam specimens reinforced with different products varied, and choosing the right product for a project depended on the pavement conditions, geosynthetic product properties, and tack coat properties. Finally, the predictive algorithms presented in this paper allow for predicting the failure mode generated by different geosynthetic products for different overlay conditions in the field, providing valuable insight for pavement engineers.