High-performance concrete is generally produced using carefully selected high quality materials. These materials increase significantly the initial costs, hence, limiting its use. In this research work the performance of concrete was enhanced through incorporating low cost untreated materials like fly ash and crushed aggregates. Thus, it can be produced enhanced or even high performance low cost concrete and, also, decrease significantly the use of cement and non-renewable natural resources (river/sea sand), contributing to the necessary sustainability of construction. From experimental program, the effect of replacing cement by fly ash (up to 60%) in the flexural tensile behaviour was evaluated, using control compositions without the addition of fly ash as a base of comparison. The results obtained demonstrate that it is possible to produce enhanced performance concrete with the selected materials replacing up to 40% of the cement by fly ash. In specimens of such mixtures, cured at least 56 days, the values of the compressive strength and the flexural tensile parameters were similar to the ones of the control mixtures.