THE EFFECT OF ADDITION ON PUMICE AND FIBER ON COMPRESSIVE AND FLUXURAL STRENGTH PRECAST LIGHTWEIGHT CONCRETE

The use of lightweight concrete is currently increasing along with technological advances, so it is necessary to do research on lightweight concrete by utilizing materials that are around the environment, such as pumice. Several studies have been carried out on lightweight concrete, using plastic or styrofoam, so that further research needs to be done on lightweight concrete by adding fiber to the lightweight concrete to produce precast lightweight concrete. This research was conducted to find out how much influence the use of pumice and and fiber on compressive strength and flexural strength of precast lightweight concrete. The addition of pumice and aggregate is divided into 4 variations, namely 0: 100, 20: 80, 40: 60, 60: 40, with the addition of 0.1% fiber. And then put into a cube and beam mold. Compressive tests were carried out on the cube and flexural tests were carried out on beams. From the test results was obtained that the addition of pumice to the concrete mixture can cause a decrease in compressive strength of the concrete from 202 kg/cm2 to 129 kg/cm2 whereas with the addition of fiber there is an increase in flexural strength is 24.48 kg/cm2. The specific gravity obtained is 1.664 gr/cm3 so this concrete is included in the "lightweight concrete" classification