Mechanical characterization for mortar for masonry

Abstract

The Eurocode 6 defines classes of mortars resistance which are based on the minimum compressive strength of mortar at 28 days after casting and suggests reference compositions for obtaining such classes. To incorporate in the National Annex of Eurocode 6, we have studied different mortar compositions usually adopted in Portugal. The mortars composition was based on the Bolomey’s formula. The mechanical characteristics of the mortar, were evaluated by laboratory tests: consistence and air content (fresh mortars); compressive and flexural tensile strength, Young’s modulus, shrinkage and fracture energy (hardened mortars). In the first phase of the study were considered six different sands: three artificial (AE - left to the limit - very fine sand, A - within the limits and AD - right to the limit - very coarse sand) and three natural (NE - left the limit - very fine sand, N - within the limits and ND - the right to limit - very coarse sand). The second phase of the study was only with the artificial and natural sand within the limits, A (artificial sand) and N (natural sand). For the same classes of resistance, the natural mortar of sand has almost better results than mortars of artificial sands; the mortars whose binder was only the cement, showed quite reasonable resistance, as well as the mortar in which was used the hydraulic lime; the mortar of cement and hydrated lime were the ones who presented lower resistance. The mortar of artificial sand has higher values of fracture energy compared to mortar with natural sand.