Effect of initial curing (no curing, 3, 7 days curing) on shear bond strength (test at 7, 28 days after demoulding) of cement sand manufacturing sand (MS) mortar

Abstract

The purpose of this research project is to find out the effect of using manufactured sand which comes from crushed rock to replace the normal nature sand to be one of the constituent in mortar to examine the influence on bond strength among interfacial zone between normal concrete substrate and manufactured sand mortar. Also, from the performance of bond strength, future application of mortar in Hong Kong construction industry can be advised. Three different fine content ( 2%, 5% and 8% ) of manufactured sand would be used ad two water-cement ratio ( 0.45 and 0.55) were adopted. Three different initial curing periods ( no curing, 3 days curing and 7 days curing) were applied to samples. The results used to analyze the shear bond strength between interfacial area of normal concrete substrate and MS mortar. The following conclusion were obtained: 1. The higher the fine content will have higher shear bond strength. 2. 0.45 w/c ratio generated a higher shear bond strength. 3. 7 days initial curing produced the highest shear bond strength. 4. 28 days to wait for the mortars to develop their highest shear bond strength.