Influence of Fine Aggregates and Specimen Geometry on Mortar Compressive Strength

The characterisation and comparison of mortars prepared with different standardised sands are essential to ensure the equivalence of results obtained under distinct national and international testing standards. The performance of mortars is heavily dependent on the physical and mechanical properties of the sand used as fine aggregates, such as particle size distribution, grain geometry, and water absorption. This study compared the standardised sand from Brazil (IPT), European sand (EN), and local sand from Porto União (Brazil), aiming to assess differences in their physical and chemical properties, their effects on mortar consistency and compressive strength, and the influence of specimen geometry (prismatic and cylindrical) on strength outcomes. The fine aggregates were characterised using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and other tests for organic matter content, humidity, and water absorption. Results showed no significant differences in aggregate morphology, except for minor variations in sphericity. Chemical composition was comparable across samples, though absorption rates were higher for European sands. Mortar consistency was also affected, with European mortars showing significant differences compared to others, and statistical distinctions between the mortars using Porto União sand and IPT sand. Specimen geometry had no significant influence on compressive strength. This research underscores the importance of understanding fine aggregate characteristics in optimising mortar performance.