Abstract
In this paper, high-volume ground scoria rocks (SR) are investigated as alternative natural pozzolanic materials to produce sustainable high-performance concrete (HPC). The effects of the source and replacement levels of up to 50% SR (by mass of cement) on the properties of HPC were investigated. Compressive strength greater than 50 MPa at 28 d was achieved for the SR replacement level of 50%. The contribution of SR to the mechanical and microstructural properties is shown to be the result of dual pozzolanic-geopolymeric-like reactions. Permeability and pore size distribution analyses were used to evaluate the contribution of SR to the mechanical improvement in the hardened concrete. Different analysing techniques were used to examine the microstructure. Comparative study of the performance of SR powders against silica fume and fly ash validated the occurrence of the dual reactions in SR mixtures. The results are encouraging and show that SR from the Arabian shield can be used as a non-traditional local source for pozzolanic material to produce durable and sustainable HPC mixtures. The use of SR at a high replacement level of up to 50% will significantly decrease cement consumption and contribute to more sustainable concrete construction in the Gulf region.