Accelerated Curing of M30 Grade Concrete Specimen Using Microwave Energy

Compressive strength of concrete mainly depends on the composition, size of the components, water content ratio, curing conditions etc. The 28 days strength is usually taken as reference strength. To find this, a moist curing of concrete specimen for 28 days is required. For economical construction, the 28 days strength is required well in advance and accelerated curing techniques are helpful to some extent. In the conventional accelerated curing, conduction of heat takes place from surface to the core of the concrete specimen and hence there exist a temperature gradient, leading to thermal stress in concrete. In this study, microwave radiation energy is used for accelerated curing in which the temperature change is uniform through out the concrete. The concrete cubes were cured with microwave energy after 6, 18 and 24 h of delay time of M30 grade concrete. Different microwave energy levels (360, 540, 720, 900 W) and microwave curing durations (20, 30, 40, 50 min) were used. The compressive strength developed after the microwave curing is compared with the 28 days strength estimated with the usual procedure. The results obtained were suitably plotted as graphs so that the graphs can be used to estimate the 28 days strength from the early strength obtained by microwave curing. The results of the study show the potential and scope for further research with different grade of concrete