Eco-friendly rehabilitation of deteriorated rigid pavements using low carbon dioxide pavement-quality geopolymer concrete

Geopolymers have gained attention for their excellent mechanical properties and eco-friendly characteristics. Investigating the bond performance between geopolymer concrete (GPC) and pavement-quality concrete (PQC) is essential for their potential in sustainable pavement repair works. In this study, the bond between PQC and pavement-quality GPC (PQGPC) was evaluated and compared with the conventional PQC–PQC interface, focusing on compressive strength, flexural strength, bond strength (pull-off and slant shear tests), fatigue life and endurance limit. The results show that after just 1 day of curing, the compressive strength of the PQC–PQGPC interface reached 21.5 MPa – a 51% increase over the 10.5 MPa for PQC–PQC. Similarly, the flexural strength improved by 60%, while the pull-off bond strength increased to 1.1 MPa compared with 0.5 MPa for PQC–PQC. Slant shear tests indicated a 75% higher bond strength. According to fatigue life studies, the PQC–PQGPC outperformed the PQC–PQC by achieving a 3% greater endurance limit for one million cycles at enhanced stress levels (0.50–0.75) and loading frequencies (10 Hz). In the PQC–PQGPC, crack propagation slowed as it transitioned into PQGPC, where minor cracks took time to widen, thus enhancing the flexural fatigue strength. These findings suggest that PQGPC, with its superior bonding properties and durability, is a promising alternative for sustainable and long-lasting concrete pavement repairs, enhancing the structural integrity of rehabilitated road surfaces.