Comparison of carbonation of lightweight concrete with normal weight concrete at similar strength levels

This paper presents a study on accelerated carbonation testing of normal weight concrete (NWC) and lightweight concrete (LWC) mixes proportioned for three levels of strength grades. Two types of curing regimes were applied; (1) hot curing in water at 60 °C for 3 days and (2) normal curing in water at 27 °C for 28 days. Pulverized fuel ash (PFA) at 25% and silica fume (SF) at 5% and 10% replacement of ordinary Portland cement (OPC) in concrete were utilized to blend binary and ternary mixes in addition to OPC mixes. The results indicated that the effect of hot water curing on compressive strength development was more prominent in PFA/SF incorporated mixes than OPC mixes. The carbonation of LWC mixes was lower than NWC mixes at similar strength levels. The mixes with 25% PFA had marginally higher carbonation than OPC mixes under both hot and normal curing. The incorporation of SF in concrete mixes also increased the carbonation. Mixes under hot water curing had higher carbonation than mixes under normal curing.