Evaluation of residual tensile strength of fire-damaged concrete using a non-linear resonance vibration method

Abstract

The non-linear resonance vibration method is a promising non-linear acoustic technique that has been used to evaluate contact-type defects of concrete induced by exposure to fire. In this work, an experimental study was performed on thin fire-damaged concrete discs to evaluate residual tensile strength using the non-linear resonance vibration method. Using correlation analysis, an experimental relationship is proposed between splitting tensile strength and a hysteretic non-linearity parameter (HNP), as measured from some 350 fire-damaged concrete discs of different mix proportions. In addition, the thermal gradient damage of concrete was examined to verify the efficiency of the proposed equation. It was found that the tensile strength of fire-damaged concrete could be effectively estimated from the measured HNP without consideration of the mix proportion, peak temperature, period after the fire or thermal gradient damage. Notation d diameter of sample F maximum applied load recorded at failure f measured resonance frequency at increased input amplitudes f 0 measured linear resonance frequency l length of sample M elastic modulus M 0 linear elastic modulus T s splitting tensile strength T s0 splitting tensile strength of undamaged sample T sn splitting tensile strength of damaged sample t time of one-dimensional (1D) dynamic behaviour of solids AE hysteretic non-linearity parameter (HNP) AE h HNP measured by amplitude-dependent resonance frequency shift AE h0 HNP of undamaged sample AE hn HNP of damaged samplẽ å strain amplitude in proportion to input amplitude å strain of 1D dynamic behaviour of solids _ å strain rate (_ å ¼ då=dt)

Evaluation of Fire-Damaged Concrete: An Experimental Analysis based on Destructive and Nondestructive Methods

“…Among these factors, it has been reported that the after-fire curing period insignificantly affects the residual material properties under an air-cured condition, while firedamaged concrete under a completely saturated curing condition appears to recover its mechanical strength (Park et al 2015). Accordingly, for a correlation analysis, the concrete samples in this study were air-cured after heating to ignore the curing condition.…”

“…Linear ultrasonic methods, which measure wave velocity, wave attenuation, and impact echo, are conventional ultrasonic methods and have been widely used to evaluate damaged concrete, particularly firedamaged concrete (Chaix et al 2003;Colombo and Felicetti 2007;Dilek and Leming 2007;Epasto et al 2010;Kee and Nam 2015;Yang et al 2009). However, these linear methods exhibit lower sensitivity to distributed defects and contacttype defects at the micro-scale (Jhang 2009;Park et al 2015) compared to nonlinear ultrasonic methods, which are more sensitive to early-stage micro-scale defects as these defects cause nonlinear behavior of an incident wave (Zaitsev et al 2006). To investigate this phenomenon in concrete, Chen et al (2010) performed an experiment to characterize microscale defects induced by an alkali-silica reaction by using a nonlinear impact resonance acoustic spectroscopy technique.…”

“…In addition, Payan et al (2007) conducted nonlinear resonant ultrasound spectroscopy to assess the damage to concrete caused by exposure to high temperatures. Moreover, recently, defects in fire-damaged concrete with various mix proportions and under various temperature scenarios have been evaluated by various nonlinear ultrasonic methods (Park et al 2015;Yim et al 2014). Park et al (2015) measured the hysteretic nonlinearity parameter (HNP) of fire-damaged concrete with various mix proportions and under various fire scenarios by using a nonlinear resonance vibration method (Van Den Abeele et al 2000a).…”

“…Moreover, recently, defects in fire-damaged concrete with various mix proportions and under various temperature scenarios have been evaluated by various nonlinear ultrasonic methods (Park et al 2015;Yim et al 2014). Park et al (2015) measured the hysteretic nonlinearity parameter (HNP) of fire-damaged concrete with various mix proportions and under various fire scenarios by using a nonlinear resonance vibration method (Van Den Abeele et al 2000a). The splitting tensile strengths of the samples were also evaluated, and the correlation between both the measurement results was reported.…”

Effect of carbonation on the linear and nonlinear dynamic properties of cement-based materials

“…This behavior can be investigated using different nonlinear resonant techniques whose basic principle is to excite the materials at their resonance frequencies at different strain amplitudes. For concretelike materials, previous studies reported that the nonlinear behavior shows enhanced sensitivity to detect alkali-silica reaction, 29 thermal damage, 30,31 and freezing-thawing damage, 32 when compared with the standard values of the dynamic modulus or relative modulus of elasticity. The present paper evaluates the variation of the linear and nonlinear dynamic properties upon carbonation of mortar samples, using resonant vibration data obtained according to the standard ASTM C215-14.…”