Effects of cork granules and hollow fly ash cenospheres on the workability, strength, and sound insulation properties of recycled aggregate mortar

This study investigated the effects of cork granules (CG) and hollow fly ash cenospheres (CS) at 0-50 vol% as damping materials on the workability, mechanical strength, and sound insulation properties of recycled aggregate mortars. Microscopic tests and engineering application experiments were conducted. The optimal dosage of CG and CS was observed to be 25 % for the mortar workability. CG and CS do not change the type of mortar hydration product; however, they have a significant effect on the interfacial transition zone characteristics and internal pore structure, thereby influencing the mortar's strength and sound insulation properties. The mortar with 7 % CS has the highest apparent density and compressive strength. However, CG consistently reduces the strength and apparent density of the mortar. At 25 % CG or CS, the impact sound insulation property becomes noticeable. CG has greater damping vibration attenuation and sound-insulating effects at middle-tohigh frequencies than CS, whereas CS more effectively isolates low-frequency noise. Overall, adding CG and CS can achieve a good soundproofing effect while maintaining the workability and mechanical properties of the mortar, suggesting the possibility of utilizing multiple types of solid waste in mortar.