The impact resistance and mechanical properties of fiber reinforced self-compacting concrete (SCC) containing nano-SiO₂ and silica fume

Abstract

In this study, an extensive study including an experimental and analytical approach describes the effects of presence 1% nano-SiO₂ and 7% silica fume on the key mechanical properties (compressive, tensile and flexural strength) and impact resistance of such compositions with inclusion of different fibre volume fractions of Polypropylene (PP) (.25, .5, .75 and 1%) and water-to-cement ratios (.27, .34, .41). The experimental tests have been implemented on two hundred and seventy specimens. Experimental results indicated that using both silica fume and nano-SiO₂ instead of cement into the plain self-compacting concrete (SCC) leads to improved impact resistance and mechanical properties. This improvement was higher in terms of impact resistance compared to mechanical properties. Moreover, it was observed that using nano-SiO₂ particles consequences to reduce the wall effect between PP fibre and its surrounding matrix. Reduction of this effect enhanced the impact resistance and mechanical properties of fibre-reinforced SCC. Moreover, a statistical/ analytical study was carried out on the executed large experimental database and it was observed that the impact resistance and mechanical properties of specimens containing silica fume and nano-SiO₂ follow a normal distribution. Furthermore, the highest rate of gaining the number of post initial crack blows to failure for the fibre-reinforced specimens registered for specimens with water-to-cement ratio of .41.

Keywords:

• fibre-reinforced SCC
• mechanical properties
• impact resistance
• silica fume
• nano-SiO₂