Influence of Nano-Silica and Polypropylene Fibers on Bond Strength of Reinforcement and Structural Lightweight Concrete

In this study, first by survey the parameters affecting the compressive strength, such as water to cement ratio, cementgrade, silica fume to cement percentage, and the various ratios of lightweight aggregate leca to total aggregate. taguchi method is used to examin optimization of the obtained 9 mix designs. since lightweight concrete is brittle like normal concrete, to resolve this problem polypropylene fibers by 0.56% and 1% ratios of concrete volume was used. moreover, to improve the mechanical properties and to study the effect of nano-silicain lightweight concrete and its effect on the adhesion between concrete and reinforcement in the mixes containing fibers, 1.5% and 3% nano-silica was added. finally, the test result of specimens at ages 28 and 90 days resulted in the best mix to get highest bond strength between lightweight concrete and reinforcement, and it was found that adding fibers and nano-silica have great effect to improve the bond strength between lightweight concrete and reinforcement.