Influence of pre-wetting, non-shrink grout, and scaling on the compressive strength of grouted concrete masonry prisms

This study experimentally investigates the influence of pre-wetting of dry masonry prisms, non-shrink grout, and grout strength on the axial compressive stress-strain response of grouted masonry prisms built using half-scale and full-scale concrete masonry blocks. To achieve the aims of this study, a total of fortytwo concrete-masonry prisms were built and tested under concentric axial load. The results showed that grouting of dry masonry prisms rendered a non-proportional increase in the prism compressive strength, whereas grouting of wet masonry prisms exhibited a significant increase in the masonry prism compressive strength. Masonry prisms constructed with non-shrink grout showed, on average, an increase in the compressive strength when compared to masonry prisms constructed with regular grout. Wetting of masonry prisms before grouting was found to enhance the compressive strength of masonry prisms. Half-scale masonry prisms showed a comparable modulus of elasticity and strain at peak strength to their full-scale counterparts. However, some discrepancies in the compressive strength and post-peak behaviour were observed. Superposition of the masonry shell and the grout core strengths was found to highly overestimate dry grouted masonry prism compressive strength, whereas wet masonry prisms demonstrated excellent agreement with superposition values. Wetting of dry masonry prisms is a promising construction procedure that significantly enhanced the compressive strength of grouted masonry; however, further research is needed to determine the proper wetting scheme and to ensure consistent results that can be quantified. (C) 2019 Elsevier Ltd. All rights reserved.