An investigation into the properties of concrete made with 10mm and 20mm aggregate

Abstract

As one can note, concrete is composed of a cement binder, aggregate and water (required for hydration). At least three fourths of the concrete is composed of aggregate thus making the aggregate quality, proportions and size of utmost importance for good concrete as the physical properties of the aggregate influence the performance of concrete. This dissertation aims to highlight the benefits and limitations of producing structural concrete made with 10mm maximum size of aggregate against concrete produced with 20mm maximum size of aggregate. The properties that are investigated include workability, tensile strength, Elastic Modulus, Poisson's ratio and finally the economics of producing concrete. Approximately 100 moulds where made out of various grades, workability and maximum size of aggregate. Tests where carried out on fresh concrete to determine whether the size of aggregate influenced the designed workability. Also, by visual inspection, the consistency of concrete and any possible sogrogntion ns n rr::mlt of n particular size of aggregate that was used in the mix was recorded. In the hardened state, the cube strength was monitored. Beams and Cylinders where tested for Flexural and indirect tensile strength and the results where compared under the same conditions varying only the maximum size of aggregate. The Static Elastic modulus of elasticity and Poisson' s ratio where also investigated from cylinders. All these investigations where carried out according to DS 1881 and DS 812. This dissertation is just the start of a series of investigations on the effects of the maximum size of aggregate on the properties of concrete and I hope that the information given in this dissertation would be of aid to anyone who decides to make further investigations.