Recycling granite and marble sludge as a construction material

Two environmental targets were addressed in this study; decreasing the demand on cement and consequently the amount of generated polluting carbon oxide by the cement industry as well as recycling the granite-marble sludge as a construction material rather than dumping it. This study presented the results of an experimental program that investigated the recycling of the sludge particles as a replacement for cement in mortars. The effect of replacement percentages 10%, 20% and 40% on the basic properties of cement and compressive strength of corresponding cement mortars were determined. Among the studied replacement percentages, the 10% provided optimum acceptable basic cementitious properties such as loss on ignition, soundness, setting times, alkalis and pH value as well as highest mortar compressive strength which fulfilled the ASTM C 150 strength limits at 3, 7 and 28 days. Also, this study showed that the sludge powder is acting as a filler material and that for mixes with sludge, one should control the actual water/cement ratio rather than the ratio of thewater to the sum of cement and sludge powder