Abstract: The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction. The invention relates to hardenable mixtures comprising cement and fly ash which can achieve greater compressive strength than hardenable mixtures containing only concrete over the time period relevant for construction. In a specific example, processing fly ash by grinding to the desired size distribution range gives a 100% yield of fly ash for utilization in high quality concrete and mortar. Such materials can thus significantly reduce construction costs, as well as provide a useful outlet for material that is generally regarded as a pollutant and a nuisance.