Attapulgite lightweight aggregate is characterized by high water absorption due to its porous structure, which may adversely affect the fresh and mechanical properties of lightweight self-compacting concrete (LWSCC). Although several surface treatment techniques have been applied to conventional lightweight aggregates, limited information is available regarding their application to attapulgite aggregate. Therefore, this study investigates the effectiveness of four surface treatment methods, namely cement paste impregnation, ceramic adhesive coating, gloss enamel paint, and polyvinyl acetate (PVA) solution, on the properties of attapulgite aggregate and the resulting LWSCC. The physical properties of the treated aggregates, including water absorption and specific gravity, were evaluated together with the fresh properties and compressive strength of LWSCC mixtures. The results showed that polymeric coating achieved the highest reduction in water absorption (approximately 46%), followed by ceramic adhesive coating (31%) and cement paste impregnation (27%) however, PVA treatment showed no measurable influence on water absorption. Also, a slight increase in specific gravity was observed after treatment due to partial pore filling by treatment products. Cement paste impregnation provided the best overall performance, where the compressive strength increased by approximately 7% and 4% at 7 and 28 days, respectively, compared with the reference mixture. On the other hand, the other treatment methods resulted in lower compressive strength due to weaker interfacial bonding between the aggregate and cement matrix. The findings indicate that cement paste impregnation is the most effective treatment technique for enhancing the overall performance of attapulgite-based LWSCC while maintaining the characteristics of structural lightweight concrete.
