An experimental study was conducted on high volume fly ash concrete (HVFA) with a constant binder content of 603.2 kg/m3 to investigate the effect of ASTM class C and class F fly ash in concrete. A constant binder content was maintained with a replacement of cement by mass of 20, 40 and 60% using both types of fly ash. The curing was done for 28, 56, 90 and 365 days. The different types of curing systems such as Accelerated curing, Warm water curing, Alternate wet & dry curing along with normal curing were done and the results were compared. Early age testing of concrete (accelerated curing and warm water curing) was conducted to predict the later age strength of concrete. Based on this relationship, the polynomial regression analysis was carried out and coefficients were proposed to find the 28, 56, 90 and 365 days strength of the HVFA concrete. © King Fahd University of Petroleum and Minerals 2013.