New Local Compression Test to Estimate In Situ Compressive Strength of Masonry Mortar

Abstract A new partially destructive test (PDT) method called local compression test method (LCTM) is proposed to estimate the in situ compressive strength of masonry mortar. In this method, the mortar pieces are taken out from horizontal masonry mortar joints and compressed mutually by means of two flat head round bars, the compressive force crushing the mortar piece is measured. The compressive test for the mortar pieces can be interpreted as the compressive strength test for the radially constrained mortar cylinder. The correction coefficient formula is first established through the tests for the local compressive strength of mortar pieces in the standard thickness (10 mm) and other thickness. The empirical correlation relationships between the local compressive strength of mortar pieces and the compressive strength of mortar cubes are presented for the masonry mortar with compressive strength ranging from M2.5 to M15.0. A good correlation between the cube compressive and local compressive strength has been found. The in situ verification tests are undertaken on a number of mortar structures to determine the accuracy of the LCTM. The experimental and analytical results show that this method is accurate and applicable to in situ tests of the masonry mortar compressive strength.