THE EFFECT OF INTERNAL AND EXTERNAL VIBRATION ON COMPRESSIVE STRENGTH OF CONCRETE

Abstract

Compressive strength of concrete mixes is shown to be dependent on stability and compactibility , significant improvement in compressive strength of dry mixes can be achieved by internal and external vibration .The internal vibration is more effective on the compressive strength of dry concrete than external vibration. The amount of incresing in compressive strength at 28 day age due to internal and external revibration was 46.27% and 31% .Time of vibration , period of initial vibration , as well as the optimum period between initial vibration and revibration which take miximum compressive strength at 7,28 day age for both external and internal revibration was determined.The value of these parameters due internal revibration are (5 minute , 15 minute , 0.5 hours ). The value of these parameters due external revibration was(10 minute , 10 minute , 3 hours ).