Enhancing the abrasion resistance of cement concrete pavement through in-situ precipitation of hydroxyapatite

• A bio-inspired method using diammonium phosphate (DAP) solution induces in-situ precipitation of hydroxyapatite (HAP) on Portland cement concrete (PCC) pavements, significantly improving abrasion resistance. • The DAP treatment resulted in a 90.56% reduction in mean profile depth (MPD) loss after 90,000 accelerated wheel load cycles. • DAP treatment increased the compressive strength of PCC by up to 15.80%, while also improving surface hardness. • The DAP treatment forms a protective hydroxyapatite (HAP) layer that seals crack and enhances the microstructure, primarily through the reaction between DAP and calcite. • This bio-inspired method offers several sustainability benefits, being environmentally friendly, low-cost, non-toxic, and locally available, making it a practical solution for pavement enhancement. This study introduces a bio-inspired approach aimed at improving the abrasion resistance of Portland cement concrete (PCC) pavements. The method involves the in-situ precipitation of hydroxyapatite (HAP), the hardest mineral in the human body, on the concrete surface through repeated treatments with diammonium phosphate (DAP) solution. Experimental results demonstrate a significant reduction in mean profile depth (MPD) loss under accelerated wheel loading, with a remarkable 90.56% decrease after 90,000 wheel loads compared to the untreated surface. In the rotating wear test, mass loss was reduced by more than 50% following DAP treatment. Additionally, the compressive strength of the PCC increased notably, with a maximum improvement of 15.80%, accompanied by a rise in surface Leeb hardness. Importantly, the DAP treatment preserved both the friction coefficient and surface texture of the pavement, as evidenced by 3D texture mapping and field tests. Thermogravimetric analysis confirmed the precipitation of HAP on the PCC surface through an in-situ reaction between DAP and calcium-rich minerals, primarily calcite, present in the concrete. Scanning electron microscopy analysis revealed a denser microstructure, primarily attributed to the formation of HAP that fills the pores. As a result, significant increases in the average indentation hardness values of the concrete surface were observed after DAP treatment. Overall, this bio-inspired method proves highly effective in enhancing the abrasion resistance of PCC surfaces, thereby significantly extending the service life of PCC pavements.