Water-retaining　semi-flexible　pavement　(WRSFP)　can　effectively　mitigate　the　urban　heat　island　(UHI)　effect　by　reducing　the　pavement　temperature　through　water　evaporation.　To　reduce　environmental　impacts　and　enhance　the　water　retaining　capacity　and　mechanical　properties　of　WRSFP,　this　paper　investigated　the　effect　of　proportion　of　water-retaining　grout　(WRG)　on　workability　of　fresh　WRG,　compressive　strength,　flexural　strength,　and　water　absorption　of　hardened　WRG　based　on　alkali-activated　slag　(AAS)　system.　The　optimal　proportion　of　WRG　was　recommended.　The　microstructure　of　the　hardened　WRG　was　observed　with　a　scanning　electron　microscope　(SEM),　which　allowed　for　a　better　characterization　and　understanding　of　the　degree　of　hydration　and　mechanical　properties　of　WRG.　The　WRSFP　specimens　(WRSFP-20%,　WRSFP-25%　and　WRSFP-30%)　with　different　porosities　of　porous　asphalt　mixture　(PAM)　were　tested　for　moisture　susceptibility,　rutting　resistance　and　low-temperature　cracking　resistance.　WRSFP-25%　had　the　best　moisture　resistance　and　rutting　resistance,　and　the　worst　low-temperature　cracking　resistance.　The　maximum　difference　of　upper　surface　temperature　between　WRSFP　and　stone　mastic　asphalt　(SMA),　which　is　commonly　used　in　pavement,　was　13.3　°C.　The　time　to　reach　60　°C　on　the　upper　surface　of　WRSFP　was　3.4　times　longer　than　that　of　SMA,　which　showed　an　excellent　cooling　effect　of　WRSFP.　©　2024　Elsevier　Ltd