Effect of mineral additives on reactive powder concrete properties

Reactive Powder Concrete (RPC) has high mechanical strength, ductility, toughness, and durability properties. RPC differs from conventional concrete with its unique mix design, production techniques, high rate of binder used, siliceous material substitution, use of new generation water-reducing chemicals at a high rate, and very low water/binder ratio. In this study, 16 different mixtures were designed to study the effects of mineral additives on the mechanical performance of RPC, the cement was replaced by silica fume (SD) as 5%, and 10%, blast furnace slag (BFS) as 40%, 50%, and 60%, pumice powder (PP) as 10%, and 20%, the cement substitution was in form of single, double and triple mixtures in different proportions. Aggregate/binder and water/binder ratios are kept constant, RPC samples were cured by two different regimes including normal water curing and laboratory room curing. Compressive strength and flexural strength tests were conducted in 3, 7, 28, and 90 days, in addition to ultrasonic velocity pulse test. It was determined that the 90-day compressive strength of the sample with 10% SF-20% PP replacement achieved 129,0 MPa, the 90-day compressive strength of the sample with 10% SF-40% BFS-20% PP replacement achieved 133,4 MPa. Also, it was observed that it is possible to produce high-performance concrete with 60-70% of cement replacement. KEY WORDS: Blast furnace slag, Pumice powder, Silica fume, Flexural strength, Compressive strength, RPC