Abstract:
Population growth and construction industry have grown beyond limits in recent decades which lead to depletion of natural resources with increasing pace. Since this resembles a serious conflict with the desired sustainability and environmental perspec tive, serious efforts are being made to use recycled aggregates in structural concrete rather than dumping in landfills. In this study, four different replacement levels (0, 50, 75, 100%), two w/c ratios were used. Also mixes containing recycled aggregates were slurry treated with slag when mixing concrete. Also, a more sophisticated method called biodeposition was applied on recycled aggregate specimens and SEM analysis were conducted prior to compressive strength tests on mixes containing bacteria treated specimens. Fatigue strength tests under uniaxial compressive loading with two differ ent Smax values (0.85 and 0.75) were applied on specimens to monitor the effects of recycled aggregates on fatigue behavior of concrete. Incorporation of recycled aggre gates into concrete adversely affected the mechanical properties. Slurry treatment were found to be effective on both mechanical performance and durability. Biodeposition treatment was found to be effective in decreasing the water absorption of recycled ag gregates. Fatigue performance of concrete containing recycled aggregates was found to be lower than natural concrete. Number of cycles to failure was more limited for recy cled aggregate specimens and these specimens were not able to withstand higher strain development and failed after a less loss of stiffness with respect to natural concrete specimens and also slurry treated specimens.
