Abstract
Abstract
The main objective of this paper is to determine the effect of silica fume on the compressive strength of concrete under two types of loading, monotonic and repeated compressive loads. Mixes were carried out by replacing cement with different percentages of silica fume of (0, 5,10,15,20) % by wt. of cement with a constant water-binder ratios 0.25. Tests on standard cylinders (300*150) mm for the different ratios of silica fume were carried out to study the behavior of concrete under monotonic and repeated loads, the load was applied for many cycles up to failure with rate of loading (0.3) N/mm2/sec. The results indicated that the addition of silica fume improves the properties of concrete giving high compressive strength, high stress and strain, stresses carried by the concrete increased by (46.3,68.8,63.1,57.5)% also the strain increased by (58.5,97.8,52.8,22)% for silica fume percentages (5,10,15,20)% for monotonic loading, and stresses increased by (44.4,68.5,63.7,56.5)% and strain increased by (45.8,68.4,51.5,26.3)% for the same percentages under repeated loads. Compressive strength, dissipated energy, and modulus of elasticity also increased with increasing silica fume percentage.
KeyWords: Silica fume, High Strength Concrete, Stress, Strain, Repeated and Monotonic Loads.
