3.2. Development of pozzolanic effect with curing tim Tables 4-6 list results of standard compressive strength and indices of pozzolanic effect at 28, 3, and 91 days after standard curing. So do Figs. 1 and 2. It is clear that compressive strength and indices of pozzolanic effect in concrete increased with curing time. During the early period (3 days of curing), the pozzolanic effect of MA was minimal. The longer the curing time, the greater the contribution of pozzolanic effect of MA to concrete strength. Therefore, curing time is an important factors on the pozzolanic effect of MA for concrete.