Influence of eco-friendly lightweight aggregates in mechanical and durability properties of geopolymer concrete

This research is to replace natural coarse aggregate as 20%, 40%, 60%, 80%, and 100% respectively, by weight in an M20 grade geopolymer concrete. The geopolymer concrete with different mixes is subjected to fresh, hardened, and durability tests. Utilization of thermal ash aggregates increased the slump and compressive strength of geopolymer concrete by about 15% and 9% respectively. Whereas the slump and compressive strength of geopolymer concrete decreased by about 30% and 38% respectively by using 100% Lightweight Expanded Clay Aggregate (LECA). Density reduction in geopolymer concrete was found by using both thermal ash aggregate and lightweight expanded clay aggregate for about 9% and 28% respectively. Thermal ash aggregate decreased the density of geopolymer concrete up to 1850 kg/m3 and improved the strength up to 24.50 N/mm2, on the other side using lightweight expanded clay aggregate, the density of geopolymer concrete drastically decreased up to 1250 kg/m3 with a huge decrease in strength up to 14 N/mm2. Other mechanical test results showed similar variations with respect to the compression test results. To ensure the durability of lightweight geopolymer concrete for mixes of GPC, TM5, and LM2 conducted tests like acid resistance, sulphate resistance, salt resistance, water absorption, accelerated corrosion, and sorptivity test.