Correlation between modulus of elasticity dynamic and mechanical strengths of cement mortars and sand with lime addition

Abstract

The quality and the durability of a mortar covering are directly related its capacity to absorb deformations, which are measured by the modulus of elasticity (Young’s modulus). This work investigated the influence of the cement, lime, and sand on the mechanical strengths and modulus of elasticity of rendering mortars, the latter calculated by the dynamic method using the PUNDIT. The effects of a natural and artificial (crushed rock) sand were also evaluated. Cement CP II Z 32 and ground lime were used to prepare 18 mortars (9 with natural sand and 9 with crushed rock sand). Cylindrical 5 cm x10 cm and prismatic 4 cm x4 cm x16 cm specimens were cast for the tests. Masonry panels 80 cm x100 cm were built and covered by a 2cm thick layer of each mortar for pull-out tests and cracks observations. The results showed that the mortars with crushed rock sand have higher modulus of elasticity than the mortars produced with natural sand, resulting in more cracks in the renderings. It was verified that the higher the sand/agglomerate and lime/cement ratios, the lower the mechanical strengths and the modulus of elasticity.