Physical–mechanical properties, and mesostructure of plain and fibre reinforced self-compacting concrete

This study analyses the mesostructural homogeneity of plain and steel fibre reinforced self-compacting concrete (SFR-SCC) to be used in slender elements of considerable height, avoiding the use of conventional reinforcement. Tests in the fresh state include the measurement of the rheological properties and self-compactability through engineering tests. Slender columns were filled with plain and SFRC-SCCs (up to 50 kg/m3 of fibres). In the hardened state, studies at the mesostructural level include the quantification through image analysis of the distribution of the coarse aggregate and fibres along the height of the columns, and measures of modulus of elasticity, compressive strength and ultrasonic pulse velocity. The physical–mechanical properties did not vary significantly along the height of the columns, though a decrease was observed in the superior third of the elements, the compressive strength was the most affected parameter. The aggregate distribution was slightly more homogeneous in the case of fibre concretes. The variation of the fibre density along the columns was relatively high, with no identifiable tendency.