Influence of Coal Waste Powder on Strength Properties of Roller Compacted Concrete Pavement

The large volumes of coal usage, and the low efficiency of the coal washing plants in Iran; induced a high percentage of refused coal in the production process, deposited as waste. Destructive environmental impacts stem from waste discharges into the natural environment, if it could be possible to replace this residue as a partial replacement of cement in order to produce concrete, damaging effects of this residue would be reduced. In this research, after pulverizing and conveying the grain size of regulation range of Coal Waste (CW) (of Mazandaran Central Alborz Washing Plant); this waste was replaced with 5, 10, 20 and 30 wt.% of cement in Roller Compacted Concrete Pavement (RCCP) mixture. Mechanical properties (compressive and tensile strength) of RCCP mixtures containing blended cement (composition of cement and Coal Waste Powder (CWP)) at the curing periods of 7, 28 and 90 days were investigated. Results show that 5% CWP replacement, will improve the strength properties of concrete mixtures up to 90 days, but declined compressive and tensile strengths was observed for RCCP mixture with CWP replacement content of 10% and 20% at different ages. Also, by increasing the percentage of CWP replacement, Ve-be time of mixture was declined.