EFFECT OF AGGREGATES TYPES ON COMPRESSIVE STRENGTH OF HIGH STRENGTH CONCRETE

Abstract

Through years of practice and experience, concrete has proven to be a suitable and crucial material in construction, and it has been successfully implemented in numerous projects. However, the recently deteriorating condition of the infrastructure constructed using concrete, has urged authorities and researchers to enhance the properties of this material. In fact there have been many efforts to improve the properties of the concrete and extend its service life. These improvements in concrete require the appropriate and careful selection of constituent materials, optimization of design and use of chemical admixtures. The process of materials designs leads to the production of high performance and high strength concrete. Because the coarse aggregate fraction in concrete occupies at least 50-60 percent of its volume, the mineralogy and surface properties of coarse aggregate exert a considerable influence on the properties of high strength and high performance concrete. The results of several experimental study show that the nature and properties of the coarse aggregate have a significant effect on the performance of concrete. This thesis presents an experimental study of the influence of coarse aggregate types on the performance and strength of concrete made with ordinary Portland cement 53 grade (OPC), silica fume (SF) undensified and SNF based superplasticiser. Four different aggregate types were used to prepare two different mixtures (M-60, M-75) made with and without the use of a silica fume, and superplasticiser. The concrete properties measured are compressive strength and modulus of elasticity. The Petrographical analysis shows that the interface between the coarse aggregate and binder plays an important role in the development of strength and performance characteristics. Type of aggregate affects the interface properties and hence the concrete characteristics.