High Performance Reinforced Concrete Beams Made with Sandstone Reactive Aggregate

An investigation on the flexural behaviour of reinforced high performance concrete (HPC) has been conducted.
Crushed sandstone known as reactive aggregate was used for both fine and coarse aggregates. In addition, mineral
admixtures such as silica fume and fly ash combined with superplasticiser was used. The beams were made with concrete
having compressive strength in the range of 74 - 88 N/mm2 and tensile reinforcement in the range of 1.34 to 3.14 %. The experimental ultimate moment was found to be about 14 - 34 % and 3 - 15 % higher than the predicted ultimate moment
based on BS 8110 and ACI 318 respectively. Due to lower stiffness of reactive sandstone aggregates, the actual deflections of the beams were found to be slightly above allowable values under service loads. The observed crack widths under service loads were within acceptable limits. It was found that HPC made with crushed sandstone coarse and fine aggregate had better structural integrity. Hence, there is a high potential to produce high strength HPC using sandstone aggregates with silica fume and fly ash