INFLUENCE OF NANO-SILICA AND POLYPROPYLENE FIBERS ON BOND STRENGTH OF REINFORCEMENT AND STRUCTURAL LIGHTWEIGHT CONCRETE (RESEARCH NOTE)

In this study, first by surveythe parameters affecting the compressive strength, such as water to cement ratio, cementgrade, silica fume to cement percentage, and the various ratios oflight weight aggregate LECA, to total aggregate, Taguchi method is used, to test 9 mix designsobtained the mix design optimization. Since lightweight concrete is brittle like normal concrete, to resolve this problem used polypropylene fibersby0.56% and 1% ratios of concrete volume. Moreover, to improve the mechanical properties and 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 will be added. Finally, by survey the test result of specimens at ages 28 and 90 days obtained 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.