Comprehensive Numerical System for Predicting Airborne Chloride Generation and Its Ingress in Concrete under Actual Environmental Conditions

Abstract

The deterioration of concrete structures in airborne chloride environments is a common problem, as attested by the large number of concrete structures in coastal areas that are in need of repair due to corrosion of steel reinforcement. Thus, to prolong the service of concrete infrastructure in marine environments, deterioration from airborne chloride should be carefully considered. However, the amount of airborne chloride is influenced by numerous factors including wind direction, wind speed, wave height, obstacles, and distance from the seashore, and the concentration of airborne chloride varies by time and location. Besides actual exposure conditions, chloride ingress depends also on the environmental condition. In order to design the concrete structures, one must consider the amount of airborne chloride, concrete qualities, and the environmental conditions. Consequently, this research aims to develop a comprehensive system that can predict chloride ingress in concrete structures by considering airborne chloride intensity at the specific locations and times, based on determination of the amount of airborne chloride generated by breaking waves and transported by wind flow. The proposed methodology can determine the chloride penetration into concrete structures in various marine environments. The numerical framework has been verified through on-site measurements to confirm its validity.

Chloride Diffusion Investigation under Different Magnitudes of Hydrostatic Pressure for Pre-Cracked Concrete

“…The aggregate size ranged from 5 mm to 20 mm with continuous grading, and its apparent density was 2630 kg/m 3 . The apparent density of sand was 2.64 g/cm 3 with a water proportion of 3.7%. The type of the water reducing agent was HP4000A with a water reduction ratio of 27.5%.…”

“…The performance of reinforced concrete structures built and served in marine environments are often degraded due to chloride-induced corrosion. Chloride ion penetration into concrete depends on a number of variables, such as chloride ion concentration, concrete's microstructures and properties, and the magnitude of hydrostatic pressure [1][2][3]. On the one hand, concrete structures are unavoidably cracked due to internal deformation and external loadings during service life.…”

Numerical Simulations of Chloride Transport in Concrete Considering Connectivity of Chloride Migration Channels in Unsaturated Pores

“…The mortar specimens were collected after three months and 3.5 years of exposure, and each specimen was ground into powder by small pitch of thickness and the total chloride amounts were measured by potentiometric titration using aqueous silver nitrate. Details of the tests are described in previous literatures (Limtong et al 2019;Wattanapornprom et al 2018).…”