Engineering property and structural design relationships for new and developing concretes

The paper reports the findings of a study carried out to investigate the effect of new and developing concrete technology solutions,e.g. (i) use of particle packing techniques and fillers to minimise voids, (ii) use of cement additions attained from industrial by-products and (iii) use of high range water-reducing admixtures which enable lower cement contents, on the engineering and structural performance of concrete and implications for structural design. The test programme considered 54 concrete mixes in three series to assess the impact of these on the tensile strength, flexural strength and modulus of elasticity of concrete, and in parallel, 37 mixes to measure these effects on the shear resistance of reinforced concrete beams. The results indicate that the influence of the concretes on compressive strength were generally inproportion to the effects on other engineering properties and were in line with current design assumptions on the behaviour of concrete. Furthermore, EC2 equations for predicting the shear strength of reinforced concrete beams, based on compressive strength, were also found to be appropriate for the range of concrete mixes considered. Overall, the work has demonstrated that new and developing concrete technology solutions can be utilised effectively within the framework of present design procedures and compressive strength is an appropriate parameter for assessing the structural performance of these concretes.