Properties of PFA Concrete at Different Curing Conditions

This paper investigates the effect of various curing conditions on the strength development and durability characteristics of PFA concrete. The concrete samples are placed in 3 different curing conditions: (i) saturated wet curing, (ii) air dried at room temperature, and (iii) sea water curing. The systems comprise of concrete mixes at decreasing water-cement ratio from 0.60 to 0.50 to 0.40 and constant PFA replacement at 30%. Neat concrete (100% OPC) and concrete incorporating both PFA and silica fume (SF) (10% SF. 20% PFA), further supports the study. Compressive strength was determined at concrete ages of 3, 7, 28 and 56 days. Water absorption test is done for samples at age of 28 and 56 days to measure the durability properties at the later ages. The study concluded that both seawater cured OPC and PFA concrete samples result in high early age strength up to 7 days. At later ages, there was no significant deterioration in strength for seawater cured concrete. Low water binder (w/b) ratio and silica fume enhance the performance of PFA concrete at all ages for all curing conditions.