Effect of Time Period between Mixing and Application of Cement Mortar on Compressive Strength

الملخص

This paper investigates the effects of time period between mixing and application of cement mortar on compressive strength. Two groups with a total of (135) cubes were cast and tested at 28 days age. In first group (81) cubes were made with different water/cement ratios (0.5, 0.6 and 0.7) without adding any additional water to correct the flow of cement mortar while in the second group (54) cubes were made with water/cement ratios (0.6 and 0.7) with adding some water to correct the flow of cement mortar. Nine different time periods were applied (0, 30, 60, 90, 120, 150, 180, 210 and 240 minutes). It was found that compressive strength of cement mortar can be reduced to 50% of the compressive strength of corresponding original cement mortar after 150 minutes from mixing water with cement.