Accelerated damage and deterioration mechanism of concrete in saline soil area and reliability analysis based on Wiener process

In order to reveal the durability deterioration mechanism and service life of concrete in the western saline soil area better, an accelerated indoor test including damage factors such as corrosion salt erosion, freeze-thaw damage, dry-wet cycle and ultraviolet radiation was designed. Macroscopic evaluation indexes such as dynamic elastic modulus evaluation parameters, quality evaluation parameters and compressive strength as well as microscopic evaluation indexes such as SEM and XRD were used to reveal jointly the deterioration mechanism of concrete durability. A nonmonotone Wiener stochastic process was proposed for modeling. The results show that: Under the coupling action of multiple damage factors, cracks and honeycomb-like pores appear on the surface of concrete internal gel, and spicules, and there are needle-like, rod-like, and chip-like crystals growing from the internal defects. Corrosion products include crystals such as ettringite, gypsum, and non-gelling brucite which consume the internal gel and produce expansion stress. The physical crystallization produced by the dry-wet cycles and the expansion-contraction stress produced by the freeze-thaw cycles intensify the formation and development of cracks. The reliability life curve can well describe the erosion degradation process of concrete under the action of multiple damage factors of saline soil. Among the degradation indexes, the reliability life obtained by quality is the longest, the dynamic elastic modulus is the second, and the reliability degradation life of the strength degradation index is the shortest. The average time of three degradation indexes at 0.35 degree of reliability is taken as the reliability life of concrete under multi damage factors, the indoor accelerated life of C45, C40 and C35 concrete is 182.3, 138.3 and 104.6 days respectively. © 2021, Editorial Board of Journal of CUMT. All right reserved.