Document Type : Research Paper
Authors
1
Associate professor, Department of Civil Engineering, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran
2
M.Sc. student, Department of Civil Engineering, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran
10.22124/jcr.2024.21928.1567
Abstract
Research records show that the replacement of microsilica and nanosilica improves the mechanical properties of concrete. Cement was replaced with microsilica at 5% and 10%; it was observed that the replacement improved the mechanical properties of concrete, which resulted in 10% better results. Cement was replaced with nanosilica in 0.5%, 1% and 1.5% and three mixes were prepared. In designs containing nanosilica, the increase in compressive strength was greater than in designs containing microsilica. The best results were related to the design containing 1.5% nanosilica. To further improve the mechanical properties and reduce cement consumption, the mixes (5%, 0.5%), (5%, 1%) and (10%, 1.5%) were also made. For compressive strength test, three standard cubic specimens were prepared at each age and each mixing design, and for split cylinder test and static modulus of elasticity, two standard cylindrical specimens were prepared, for a total of 117 specimens. Compressive strength tests were performed on water-cured specimens at 7, 28 and 91 days of age. Split cylinder and modulus of elasticity tests, were performed on water-cured specimens at 28 days of age. Simultaneous replacement of some cement with microsilica and nanosilica in small percentages resulted in a significant improvement over their separate use. 10% microsilica and 1.5% nanosilica design are determined and introduced as the optimal design. In the optimal design, the increase in compressive strength and split cylinder test as well as modulus of elasticity at the age of 28 days were 70%, 115% and 29%, respectively, compared to the reference design.
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