Estudio del comportamiento del acero de refuerzo expuesto al fuego durante diferentes periodos de tiempo

Abstract

This experimental work aims to study the behavior of reinforcing steel exposed to heat during different periods of time. Thus, determined tensile strength, ductility and elongation of the steel reinforcement. The steel reinforcements were extracted of reinforced concrete beams with strength were of 210 Kg/cm², these reinforced concrete beams were cured in the laboratories of the Faculty of Civil Engineering and mechanics, once concrete reaches its maximum resistance to compression at 28 days of age the beams were classified into two groups, not exposed to fire beams and the beams exposed to fire to different time periods. These specimens were burned in a furnace at different intervals of time such as: 30 minutes, 60 minutes, 90 minutes, 120 minutes, 150 minutes, 180 minutes with temperatures (820° C, 940 C, 980° C, 1000° C, 1100° C, 1150° C), these specimens went through a 24 hours friendly cooling process, then proceeded to break the concrete to obtain the steel reinforcement, prior to a tensile test proceeded to the identification and preparation of the dimensions of 50 cm to obtain a zone calibrad a or 20cm test area, was verified trials that the reinforcing steel has a 4200 PSI yield strength based on the standard of the Ecuadorian Institute for Standardisation (INEN 2167). Identified different levels of tensile strength of test specimens exposed to fire to a temperature greater than 1000° C decreases considerable mind their resistance 16.24% causing loss of section, cracking, crack resistance and cracking of the steel reinforcement.