Efficiency of Silica Fume and Fly Ash in Road Concrete

The paper presents the experimental results of studies on green road concrete prepared by replacing the cement with waste silica fume and fly ash in different dosages. The cement was in three dosages:330 kg/m3, 360 kg/m3 and 380 kg/m3 and was replaced by silica fume or fly ash in percentages of 10%, 20% and 30%. The river aggregates were in four sorts. The mechanical properties such as flexural strength, compressive strength and split tensile strength were experimentally determined and discussed. All mechanical strengths that were determined in laboratory presented values smaller than that of control road concrete (that was without substitution of cement), the decreasing percentage increased with increasing the cement substitution dosage. The flexural strength and compressive strength for concretes with fly ash were higher than the values of flexural strength and compressive strength of mixes with silica fume. The use of silica fume or fly ash waste for preparing green road concrete results in good values of mechanical strengths.