H Azizian, and F Riahi
The process of taking strength in the concrete , depends on several factors, that the most important ones can be mentioned as stone materials for forming concrete . stone materials ratio is always as one of the most critical parameters in determining the compressive strength of concrete . Therefore, in this study, with a fixed Mixture Design and changes in the ratio in fine and coarse aggregate , We have covered the vitro evaluation of the changes of compressive strength in the samples in each On days 7, 28 and 90 days according to ASTM standard , and the rate of changes in the compressive strength of the samples were studied . From results revealed that at the age of 7 days compressive strength changes in two Mixture Design is about 10 percent, and in the older ages this will change less than 5% .