Impact of recycled gravel obtained from low or medium concrete grade on concrete properties

This paper investigates the effect of recycled gravel obtained from low (Gl) or medium (Gm) concrete grade on fresh property of concrete (slump), mechanical properties (compressive-splitting tensile strength) and mass transport properties (ISAT-sorptivity) of concrete containing dolomite as a natural coarse aggregate. Concrete specimens were prepared with cement, water, sand and dolomite admixed with recycled gravel. The percentage of recycled gravel/dolomite was 0:100, 25:75, 50:50 and 75:25 at w/c = 0.50, 0.55 and 0.60. The effect of silica fume and bonding admixture at w/c = 0.55 on concrete properties were also considered. The results indicated that, increasing the percentage of recycled gravel/dolomite led to decreasing the slump. All mechanical properties of concrete discussed were inversely affected by increasing percentage of recycled gravel/dolomite from low and medium concrete. Adding 10% SF or bonding admixture increased the mechanical properties of concrete. Mass transport properties of concrete (ISAT-sorptivity) were enhanced by decreasing the percentage of recycled gravel/dolomite. The optimum percentage of recycled gravel/dolomite = 25%.