Analisis Kuat Tekan Beton Mutu Tinggi Pasca Bakar Menggunakan Serat Polypropylene

Abstract

High-strength concrete is vulnerable to high temperatures due to its high density. The use of polypropylene fibers could prevent structure explosion by forming canals due to melted fibers during fire, thus release its thermal stress. This study aims to determine the effect of polypropylene fibers on compressive strength of high-strength concrete after combustion at 400ºC for five hours. High-strength concrete was made by w/c-ratio 0.3 with cement amount 550 kg/m³ and added with silica fume 8% and superplasticizer 4% by cement weight. The variations of polypropylene fibers were 0%, 0.2% and 0.4% of concrete volume. The compression test was carried out on standard cylinders Ø15/30 cm of combustion and without combustion specimens at 7 and 28 days. The results showed that compressive strength of high-strength concretes without using polypropylene fibers decreased in post-combustion compared with specimens without combustion, i.e., 0.81% at 7 days and 23.42% at 28 days. Conversely, the use of polypropylene fibers can increase post-combustion compressive strength with a maximum value resulted in adding 0.2% which are 25.52% and 10.44% at 7 and 28 days respectively. It can be concluded that the use of polypropylene fibers is effective to prevent reduction of high-strength concrete compressive strength that are burned at high temperatures.