In this paper, to study the development of load-carrying capacity and long-term creep performance of reinforced concrete beams under different corrosion patterns, the rate-dependent model of concrete is used as the basis to consider the creep development process from the meso-scale level. The porosity mechanics method is used to simulate the generation and penetration process of corrosion products. Three corrosion conditions are set: bottom longitudinal reinforcement corrosion, top longitudinal reinforcement corrosion and all reinforcement corrosion.
View Article and Find Full Text PDFTo meet the requirements of durability design for concrete suffering frost damage, several test standards have been launched. Among the various damage indexes such as deteriorated compressive strength, relative dynamic elastic modulus (RDEM), residual deformation, etc., the concept of a "Durability Factor" (DF) is proposed by many standards to define the frost resistivity of concrete against frost action based on the experimental results from standard tests.
View Article and Find Full Text PDFUltrasonic testing (UT) is an important method for concrete, and ultrasonic pulse velocity is commonly used to evaluate the quality of concrete materials in existing studies. The ultrasonic pulse velocity of concrete materials is affected by many factors; therefore, it is necessary to establish a quantitative prediction model for the ultrasonic pulse velocity of concrete materials. Based on the multiscale homogenization method, concrete material is divided into different scales of homogenized materials, namely cement paste, mortar, and concrete.
View Article and Find Full Text PDFElectrical measurements are promising for evaluation of frost damage of concrete, but the index is still controversial. In this paper, to propose an efficient index, various electrical characteristics were examined to correlate them with the mechanical property degradation of meso-scale mortar samples due to combined effects of sodium chloride and freeze-thaw cycles (FTCs). While the electrical responses of specimens were measured during FTCs, the mechanical properties were obtained from three-point bending tests after FTCs.
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