Waste silica sand as a possible pozzolanic filler to produce cement mortars: experimental investigation

The present paper discusses experimental results obtained on several mortars prepared using a commercial type1 OPC cement, a commercial limestone aggregate with maximum particles dimension below 5 mm, superplasticizer and water. Different amounts of a waste silica sand, in form of loose powder, derived from the industrial production of refractory blocks, were added to the above basic components. Several additional samples were also prepared using same basic commercial components added by different amounts of a fine limestone filler. This latter set of compositions was used to prepare samples to be used as reference materials. Waste silica sand and fine limestone filler were used as received from their producer. During preparation, pastes containing silica sand showed better workability compared to all the other blended components. All hydrated materials displayed fair compressive strength and low water absorption after curing, but those containing silica sand showed the best mechanical performances due to their low residual porosity and to the pozzolanic reaction which could enable application for the production of structures in direct contact with water or aggressive environments such as sewers or tanks suitable for the containment of organic substances.