Comparative evaluation of properties of laboratory test specimens for masonry mortars prepared using different compaction methods

Development of new solutions for masonry mortars is heavily reliant on laboratory-based experimental procedures. This study provides insights into the properties of masonry mortars, prepared by four distinct compaction methods, based on existing standards: tamping, tapping, jolting and vibrating. The particular mortar mix under study has been designed in volumetric proportions of 1:1:6 with air lime, cement and sand, respectively. Evaluation of differences among compaction methods is based on bulk density, mechanical strength, porosity and water absorption measurements at 7 and 28 days. Density and strength testing results indicate statistically significant differences, where mechanically compacted mortars are denser and stronger than their manually compacted counterparts. Similar development is observed through assessment of mortar porosity. The variation is noticeable in gel and capillary pore range as shown by mercury intrusion, while open porosity evaluated by vacuum immersion also indicates some distinction between manual and mechanical compaction, with the latter producing less porous mortars. On the other hand, capillary water absorption results reveal higher coefficients for jolted and vibrated samples, hinting at different pore interconnectivity in mechanically and manually compacted mortar specimens.