Mechanical Properties of Ultra High Performance Concrete with calcium carbonate as a substitute of cementitious material

The influence of calcium carbonate -as a filling material- on the mechanical properties of an Ultra High Performance Concrete (UHPC) featuring silica fume and cement as cementitious materials, was evaluated. Properties like compressive, flexural, and tensile strength, as well as the elastic modulus were evaluated for three different calcium carbonate substitution rates (47%, 35,5% and 24%), and were all compared to a reference mixture of UHPC with no substitution. A better packaging of dry materials, leading to improvement in compactness and resistance, was observed when a higher quantity of calcium carbonate was used. Results of 56-day-compressive strength were higher for samples with calcium carbonate compared to those of the reference mixture, but presented a different trend for other properties. Temperature measurement led to develop a viable methodology to substitute the cementitious material for carbonate calcium or any other filling material.