Estimation of in situ masonry mortar compressive strength using hammer pendulum test method

The compressive strength of in situ masonry mortar was evaluated using the hammer pendulum test method (HPTM). A portable HPTM apparatus, specifically designed for this purpose, was used to indirectly evaluate the compressive strength of mortar by inserting steel nails into the horizontal mortar joints of the masonry and measuring the penetration depth. The discrete attributes of the test outcomes were analyzed to ascertain the repeatability and reliability of the HPTM results. A relationship between penetration depth and compressive strength was established. In comparison with other existing testing methods, the results confirmed that the HPTM is an alternative compression testing method for masonry mortar, with the advantages of high accuracy, minimal preparation work and good repeatability. The mortar compressive strengths estimated using the HPTM were reasonably consistent with the results of compressive strength tests on mortar cubes.