Effect of Untreated Recycled Aggregate on Properties of GPC

This research article provides a comparison of various properties of geopolymer concrete on the complete substitution of natural aggregate with untreated recycled aggregate. In total, 4 design mixes were prepared, out of which 2 design mixes were of traditional concrete, while the other 2 were of geopolymer concrete (GPC). In GPC, curing temperatures of 60 and 90 ℃ and three curing periods (i.e., 24, 48, and 72 h) were adopted. The mix composition of aggregates was decided using the particle packing method. The specimen testing was done after 7 and 28 days of casting. The GPC density is about 3% less than that of OPC. As the curing temperature rose for both natural and recycled aggregate concrete, an improvement in mechanical properties was observed. The study further compared the UPV value of OPC and GPC.