Influence of Initial Damage Degree on the Degradation of Concrete Under Sulfate Attack and Wetting–Drying Cycles

• Main Authors: Yujing Lv, Wenhua Zhang, Fan Wu, Huang Li, Yunsheng Zhang, Guodong Xu
• Format: Article
• Language: English
• Published: SpringerOpen 2020-08-01
• Series: International Journal of Concrete Structures and Materials
• Subjects: initial damage; sulfate attack; wetting–drying cycles; mass loss; relative dynamic modulus; compressive strength
• Online Access: http://link.springer.com/article/10.1186/s40069-020-00422-z
• ISSN: 1976-0485; 2234-1315

Abstract The previous researches on the degradation process of concrete under sulfate attack mainly focus on non-damaged concrete. It may lead to an excessive evaluation of the durability of the structure, which is detrimental to the safety of the structure. In this paper, three different damage degrees of concrete specimens with non-damaged (D 0) and initial damage of 10% (D 1) and 20% (D 2) were prefabricated and subjected to sulfate attack and wetting–drying cycles. With the increase of sulfate attack cycles (0, 30, 60, 90, 120, 150 cycles), the changes in mass loss, relative dynamic modulus of elasticity, and the stress–strain curve were studied. The results show that the mass of the D 0 specimen had been increasing continuously before 150 sulfate attack cycles. The mass of D 1 and D 2 had been increasing before 60 cycles, and decreasing after 60 cycles. At 150 cycles, the mass loss of D 0, D 1, D 2 were − 1.054%, 0.29% and 3.20%, respectively. The relative dynamic modulus of elasticity (RDME) of D 0 specimen increases continuously before 90 sulfate attack cycles. After 90 cycles, the RDME gradually decreases. However, for D 1 and D 2 specimens, the RDME began to decrease after 30 cycles. The damage degree has an obvious influence on the compressive strength and elastic modulus. For the D 0 specimen, the compressive strength and elastic modulus increased continuously before 90 cycles and decreased after 90 cycles. The compressive strength and elastic modulus of D 1 and D 2 specimens began to decrease after 30 cycles. The stress–strain curves of concrete with different initial damage degrees were established, and the fitting results were good. Finally, based on the analysis of experimental data, the degradation mechanism of concrete with initial damage under the sulfate wetting–drying cycle was discussed.