Compressive strength of re-vibrated concrete made from pebbles

Department of Civil Engineering, School of Infrastructures, Process Engineering and Technology, Federal University of Technology, P. M. B., 65, Minna. Niger State. Nigeria.

^* Corresponding author: samuel.auta@futminna.edu.ng

Abstract

The search for natural and readily available structural material to meet the growing demand for ecologically friendly and smart structures is an ongoing development. In this background, an experimental study into the compressive strength of re-vibrated concrete made from pebbles as coarse aggregate is presented. Fifty-six (56) concrete cubes were cast adopting a re-vibration time lag interval of 10minutes for one hour, with a target strength of 15N/mm². This comprised 28 cubes 100% granite and 28 cubes 100% pebbles as coarse aggregates respectively. Two curing ages were considered: 7 and 28 days. Results from the compressive strength tests of the cured specimens showed that: at successive time lag intervals there was an appreciable rise in compressive strength of concrete; observable was also a rise in the compressive strength with an increase of curing age. However, even though the maximum compressive strength of 25.64N/mm² for 100%granite was achieved, that of 100%pebbles attained 23.33N/mm², both at 60th minute of re-vibration time lag respectively. Hence, it can be suggested that 100% pebbles replacement for granite can be used to produce concrete with compressive strength of up to 23N/mm² when revibrated.