The Effect of Concrete Sample Size in the Compressive Strength Value of Concrete

Concrete is one of the most widely used construction materials. Compressive strength is one of the most important properties of hardened concrete. Different codes use different standards to define the characteristic strength. Albania nowadays is adapting the EN standards, but previously it used to apply the local code KTP. According to KTP standards the concrete samples were cubic specimens of 200mm side length. This study is an attempt to analyse the relation between sample size and compressive strength values of concrete specimens. For this purpose, 4 concrete classes of C8/10, C16/20, C20/25, C30/37 and 5 different cubic sizes of 50, 100, 150, 200, 250mm side length were investigated. The samples were taken according to EN 206-1. Six samples were tested for the determination of the compressive strength value of each class/size combination. According to the compressive strength test results the values increase as the size increases up to 150mm, but as the cube size continues to increase the compressive strength values decrease gradually