Quantification of plastic shrinkage and cracking in mortars containing different recycled powders using digital image correlation technique

Abstract

This research assessed the shrinkage of mortar containing recycled powder generated from aerated blocks and bricks by replacing cement with a ratio of 30%. Five mix proportions were formulated to prepare mortar plate specimens. AP represents the mixes with aerated block powder and BP represent the mixes with sintered brick powder. Among all of the mixes, AP1 and BP1 was formulated at the same water binder ratio as that of the reference mix, and the same fluidity as the reference was maintained in AP2 and BP2 by adjusting the water content. Digital image correlation (DIC) technique was used to evaluate the strain distribution during the plastic shrinkage stage. The results showed that the mortar containing the aerated block powder presented a higher risk of cracking. On the contrary, the brick powder had a lower water requirement, as a result, a lower risk of cracking. The aerated block powder particles contain pores of 2–3 μm size, which seriously reduces the fluidity of the mortar and causes a tremendous shrinkage.