Study On The Effect Of Temperature And Burning Time On The Concrete Compressive Strenght In Mining Laboratory, Department Of Mining Engineering, Faculty Of Engineering Bandung Islamic University

Abstract

Concrete is the main material to construct a building or infrastructure. The need of a construction makes concrete as a main choice because it’s easy to be formed. Materials used to make a concrete have an important impact on the concrete’s strength. In a condition, it’s necessary to have concrete with certain specifications, such as lightweight concrete, heat resistance concrete, reinforced concrete, and other uses. Concrete has a heat resistance to a certain temperature until it is damaged or experiences structural failures. A concrete burned at high temperature will reduce its compressive strength and cause a structural failure. Concrete should not be dehydrated or experience a lack of water content because it will affect the connective power of each aggregate inside. In this study, the concrete samples are burned in the blast furnace at temperature of 200°C, 400°C and 500°C for 30, 60, 90 and 120 minutes to determine how far the scope of these variables affect the concrete. The samples of concrete which are not burned are also tested to be compared with the compressive strength of the burned samples. The samples used are the concrete with medium quality specifications with compressive strength of 21 MPa to 40 MPa. The compressive strength test executed on the burned concrete samples, results the whole samples experience a diverse of compressive strength value decrease. This occurs due to damaged ties between the cement hydration ties and rough aggregate (split rock) and soft aggregate (sand) as the consequence of reduced number of water that helps the bond. In the end, the strength of concrete samples are reduced and resulted a structural failure. The not burned concrete samples compressive strength median is 23.31
MPa. While the concrete samples burned at a temperature of 200°C has the compressive strenght value of 18.60 MPa (30 minutes), 16.98 MPa (60 minutes),15.36 MPa (90 minutes), 13.74 MPa (120 minutes). At temperature 400°C, the compressive strength of concrete samples are 13.87 MPa (30 minutes), 13.06 MPa (60 minutes), then 12.25 MPa (90 minutes), 11.44 MPa (120 minutes). The compressive strength of concrete samples at combustion temperatures of 500°C are 11.09 MPa (30 minutes), 9.77 MPa (60 minutes), 8.45 MPa (90 minutes), 7.13 MPa (120 minutes). The coefficient correlation temperature effect is 0.976 with time effect 0.927, and time and temperature effect is 0.977. This indicates that time and temperature have a very high effect. Based on the results of the test, the compressive strength of concrete samples does not meet the standards of moderate concrete quality.