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

Abstract

Abstract. Carbonation causes a physicochemical alteration of cement-based materials, leading to a decrease of porosity and an increase of material hardness and strength. However, carbonation will decrease the pH of the internal pore water solution, which may depassivate the internal reinforcing steel, giving rise to structural durability concerns. Therefore, the proper selection of materials informed by parameters sensitive to the carbonation process is crucial to ensure the durability of concrete structures. The authors investigate the feasibility of using linear and nonlinear dynamic vibration response data to monitor the progression of the carbonation process in cement-based materials. Mortar samples with dimensions of 40 × 40 × 160 mm were subjected to an accelerated carbonation process through a carbonation chamber with 55% relative humidity and >95% of CO 2 atmosphere. The progress of carbonation in the material was monitored using data obtained with the test setup of the standard resonant frequency test (ASTM C215-14), from a pristine state until an almost fully carbonated state. Linear dynamic modulus, quality factor, and a material nonlinear response, evaluated through the upward resonant frequency shift during the signal ring-down, were investigated. The compressive strength and the depth of carbonation were also measured. Carbonation resulted in a modest increase in the dynamic modulus, but a substantive increase in the quality factor (inverse attenuation) and a decrease in the material nonlinearity parameter. The combined measurement of the vibration quality factor and nonlinear parameter shows potential as a sensitive measure of material changes brought about by carbonation.

Feasibility of Application for the SHG Technology of Longitudinal Wave in Quantitatively Evaluating Carbonated Concrete

“…During the progress of concrete carbonation, the existing pores and microcracks are deposited by the carbonation product CaCO 3 . The molar volume of carbonated products is higher than that of hydrates, resulting in a decrease in the porosity of concrete and an increase in the density of concrete [3,4]. Then the fundamental amplitude A 1 increases while the harmonic amplitude A 2 decreases as ultrasonic attenuation decreases.…”

“…The spectrum was verified to detect carbonation reaction early. During concrete carbonation, the pores and microcracks in concrete change as a result of the carbonation products [3,4], and these changes significantly impact the material non-linearity. The feasibility of the non-linear Resonant Ultrasound Spectroscopy (NRUS) technique was verified by Bouchaala et al [5] in concrete carbonation by measuring the resonant frequency shift of the signal in a given mode with the resonant peak amplitude [5,6].…”

Effect of Temperature on Ultrasonic Nonlinear Parameters of Carbonated Concrete

“…Bouchaala et al [4], reported that resonant ultrasonic nonlinear parameters have the feasibility of measuring concrete carbonation. Eiras et al [5] used resonance ultrasonic spectroscopy technology to study the effect of concrete carbonation on the linear and nonlinear dynamic properties of cement-based materials. The linear and nonlinear dynamic properties can be used to deem material against carbonation in laboratory tests, whereas concrete has inherent nonlinearity due to its material composition.…”

Linear and nonlinear resonant ultrasonic techniques applied to assess delayed ettringite formation on concrete samples

“…Still, the need for new physical parameters that provide further information on the mechanical performance of concrete upon DEF has been claimed in several study reviews [9][10][11]. In recent years, the evaluation of the nonlinear mechanical behavior through resonant experiments has been satisfactorily applied to assess different durability distresses in concrete, such as alkali-silica reaction [12][13][14] freezing-thawing damage [15][16][17], thermal damage [18,19], and carbonation [20,21]. The evaluation of the nonlinear properties of concrete upon the development of DEF has seldom been studied.…”