Determination residual strength concrete of post-fire using ultrasonic pulse velocity

Abstract

Assessment of residual strength of concrete post fire is importance. Concrete exposed at high temperatures causes chemical and physical phenomena that cause various level of damage. Heat distribution unevenly causes different of hot spots on the concrete surface. The correlation between high temperature and duration heat raises the heat penetration depth differently which effect on the strength of concrete. The research aims determine substantial reduction of the compressive strength concrete the post-fire as result of the depth of heat penetration. Experimental method by vertical furnaces was used in this research. Specimens use two of the concrete panel which has 1065 mm x 1055 mm and 100 mm thickness and ten the cylinder concrete with the diameter 150 mm and 300 mm height. Combustion of the specimens was performed with gradual heat follow the heat curve according to SNI 1741: 2008. The combustion duration carried out for 2 hours and an hour that result the depth heat penetration differently. The depth heat penetration was measured with a set thermocouple that has embedded in the concrete panels with various depths. The residual concrete strength post-fire was measured using ultrasonic pulse velocity.