POROSITAS, KUAT TEKAN DAN KUAT TARIK BELAH BETON DENGAN AGREGAT KASAR BATU PECAH PASCA DIBAKAR

Abstract

Porosity can be defined as a ratio of pore volume (volume occupied by
the fluid) to total volume of concrete. Porosity in concrete is important to be
studied; especially for materials of seaside buildings and buildings attaching the
ground. Salt water containing sulfate and chloride can press the pores of concrete
so that concrete cracks into loose flakes and its strength reduces. An increase in
porosity is thought to associate with a reduced strength of post-burnt concrete.
Research was conducted to study the compressive strength, splitting tensile and
porosity of post-burnt concrete using cylinders of 150 mm diameter and 300 mm
high. Burning of samples was carried out after 28 days of age. The burning was
started at an oven temperature of 34 º C until it reached a maximum temperature of
± 800 º C achieved at minute of 180 and then it held on for another 20 minutes, so
that the burning process lasted for 200 minutes. The test results showed that the
increase in porosity of concrete is proportional to the volume of concrete that had
hot penetration with temperature 400-800 oC. The porosity of concrete increased by
20.695%, which resulted in the decrease of compressive strength and splitting
tensile strength by 53.665% and 49.641% respectively.