The Influence of Concrete Cylinder Size on Compressive and Tensile Strength of Semi Lightweight Pumice Concrete

Concrete strength is affected by many complicated factors, one of them namely specimen size. Concrete quality control is commonly based on testing on concrete specimen, such as cylinders, or drilled Cores. The specimens like cores are various in sizes and consequently they do not conform to the specification of building code. Because the different size of concrete cylinder is probably encountered, then it is important that the mechanical properties of Self compacting lightweight concrete be discovered. This research is to explore the influence of concrete cylinder size on mechanical properties of Self compacting semi lightweight concrete and to recommends correction factor of concrete strength tested with different cylinders size to that of the standard concrete cylinder. Variables considered are h-d ratio and diameter of the concrete cylinder. The research focuses on behavior of Compressive and Tensile strength of Self compacting semi lightweight concrete. All specimens are concrete cylinders and mix proportion is kept constant, 1:1:2 of cement-sand-coarse aggregate ratio by volume, with a water-cement ratio of 0.45. The coarse aggregate is pumice with nominal maximum size of 20 mm. From observation, the concrete strength is linearly reduced as the diameter of the concrete cylinder increase. Concrete cylinders with height-diameter ratio of 2 give the optimum compressive strength and optimum tensile strength of each sample. Some correction factors that can be utilized for correcting both the compressive and tensile strength tested with various cylinders size to that of the ASTM standard concrete cylinders are also recommended