Micro and macrolevel properties of fly ash blended self compacting concrete

This investigation is mainly focused on the effect of class F fly ash on the micro and macrolevel properties of self compacting concrete (SCC) after 28, 56 and 112 days of curing. The microlevel properties studied were the microcrack widths between aggregate and paste and atomic Calcium–Silica (Ca/Si) ratio. The macrolevel properties studied were compressive strength, modulus of elasticity and splitting tensile strength. A conventional concrete (CC) having an equivalent 28-day SCC compressive strength has also been examined at different ages. Scanning electron microscope (SEM) analysis was carried to examine the width of microcracks and energy dispersive X-ray analysis (EDAX) was carried out to determine the chemical elements of both SCC and CC. Studies revealed that pozzolanic action of class F fly ash improved the microlevel properties of SCC with age by reducing the microcracking width and Ca/Si ratio and thus enhanced the macrolevel properties.

► Effect of class F fly ash on micro and macrolevel properties of self compacting concrete is studied.
► Decrease in microcracking width and Ca/Si ratio was observed in SCC with the age.
► Micro and macrolevels properties of SCC were compared to those of conventional concrete.
► Micro and macrolevel properties of SCC are reasonably correlated.
► Recommendation of SCC mix with medium compressive strength of 32 MPa for the building constructions.