Mechanical properties of ultra-high performance concrete based on reactive powder concrete: Effect of sand-to-cement ratio, adding glass fiber and calcium carbonate

Abstract

Reactive Powder Concrete (RPC) contains high amounts of cement. This high ratio increases causing issues such as a high hydration temperature and concrete shrinkage. The present investigation is an attempt to study the effect of Sand-Cement ratio, substitution of calcium carbonate with part of Silica sand and adding glass fiber, on the properties of RPC. The study also deals with the microstructure investigation and Thermo-Gravimetric Analysis of RPC. Results indicate that increasing the S/C ratio up to 1.2 can improved the properties of RPC by reducing the amount of cement used. On the other hand, substitution 40%-50% of the silica sand with calcium carbonate can improved the microstructure of RPC. Moreover, the tensile behavior of RPC must be improved using another material due to the limit on the largest grain size in it. Adding glass fibers equivalent to 8%-10% of the cement weight to the mix design of RPC (containing 40%-50% silica sand that was replaced with calcium carbonate) improves the mechanical and durability behavior of RPC.