A pilot study of methods for measuring the residual properties of concrete exposed to elevated temperatures

A pilot study of methods for measuring the residual properties of concrete exposed to elevated temperatures

Článek WoS

This pilot study and literature review was performed with the purpose of preparing for subsequent extensive research focused on the design of effective diagnostic methods for determining the current state of concrete structures damaged by high temperatures during exposure to fire. During the pilot study, specimens were prepared from ordinary concrete with dense aggregate, and were subsequently loaded by temperatures of 200, 400, 600, 800, 1000 and 1200 °C. One set of the specimens was kept as reference specimens without thermal loading. After the thermal loading of the six sets of specimens had cooled, selected non-destructive tests were performed; namely the SilverSchmidt hammer rebound test, the ultrasonic pulse velocity test, and the impact-echo method. Furthermore, the compressive strength of the specimens was determined destructively to provide reference data. The experiments indicated the fact that the commonly used non-destructive methods are not suitable for estimating the compressive strength of concrete exposed to temperatures higher than 600 °C. This indicates that it is necessary to derive new calibration relationships for such conditions. It was also found that an apparent increase occurred in the hardness and modulus of elasticity of the tested concrete when it was exposed to temperatures greater than 1000 °C.

This pilot study and literature review was performed with the purpose of preparing for subsequent extensive research focused on the design of effective diagnostic methods for determining the current state of concrete structures damaged by high temperatures during exposure to fire. During the pilot study, specimens were prepared from ordinary concrete with dense aggregate, and were subsequently loaded by temperatures of 200, 400, 600, 800, 1000 and 1200 °C. One set of the specimens was kept as reference specimens without thermal loading. After the thermal loading of the six sets of specimens had cooled, selected non-destructive tests were performed; namely the SilverSchmidt hammer rebound test, the ultrasonic pulse velocity test, and the impact-echo method. Furthermore, the compressive strength of the specimens was determined destructively to provide reference data. The experiments indicated the fact that the commonly used non-destructive methods are not suitable for estimating the compressive strength of concrete exposed to temperatures higher than 600 °C. This indicates that it is necessary to derive new calibration relationships for such conditions. It was also found that an apparent increase occurred in the hardness and modulus of elasticity of the tested concrete when it was exposed to temperatures greater than 1000 °C.

Concrete, high temperature, Schmidt rebound, ultrasonic pulse velocity

Concrete, high temperature, Schmidt rebound, ultrasonic pulse velocity

ROZSYPALOVÁ, I.; DANĚK, P.; ŠIMONOVÁ, H.; KERŠNER, Z.; KOCÁB, D.

2019

01.06.2018

IMT Ljubljana

Ljubljana, Slovenija

1580-2949

Materiali in Tehnologije

52

3

Slovinská republika

243

252

10

http://mit.imt.si/Revija/izvodi/mit183/rozsypalova.pdf