Abstract
This study develops lightweight expanded clay aggregate (LECA) from local low-expanding loams using an oil-sludge-based fuel-containing additive and evaluates its use in vibro-pressed lightweight aggregate concrete (LWAC) wall blocks. LECA was produced by granulation and firing, then characterized by bulk density, water absorption, and compressive strength. LWAC blocks were manufactured via a semi-dry vibro-pressing route and tested for density, compressive strength, thermal conductivity, and freeze-thaw resistance. The LECA incorporating oil sludge showed a strength increase from 1.38 MPa to 2.8-3.1 MPa with a moderate density rise (316 to 350-400 kg/m3) while maintaining ~25.8% water absorption. Blocks achieved 800-950 kg/m3 density and 10-12 MPa compressive strength, with 0.75-0.8 W/(m·K) thermal conductivity and 50-75 freeze-thaw cycles. XRD pattern fitting indicated silicate- and spinel-type crystalline phases, though some matches require verification. Overall, the raw material and processing route enable structural wall units with improved thermal performance. The future work should prioritize moisture-related durability under higher saturation.