Evaluating the chloride permeability of steel–concrete interface based on concretes of different stability

Abstract

The deterioration of reinforced concrete structures caused by chloride‐induced corrosion is a major threat to their service life. Previous studies show that defects in the steel–concrete interface have a significant impact on the corrosion process of steel bars. Study on the chloride permeability of steel–concrete interface is very important for revealing the mechanism. In this article, we devised a new experimental method named chloride penetration depth test which was used to evaluate the chloride permeability along the steel–concrete interface. Two types of fresh concretes, normal concrete (NC) and lightweight aggregate concrete (LWAC) with obviously different stability, were designed to obtain specimens of various defect sizes in the steel–concrete interface. The results show that the chloride penetration depth measured with the new method increased with the defect size in the steel–concrete interface determined by backscattered electron (BSE) imaging and nanoindentation technology, indicating that the chloride permeability of steel–concrete interface could be identified by the method we proposed.

Influence of coarse aggregate settlement induced by vibration on long-term chloride transport in concrete: a numerical study

“…Panesar and Shindman [11] also reported that the transport properties varied along the casting direction, and the durability performance was worse for the top surface of concrete specimens in comparison to the bottom surface. In authors' prior studies [12,13], it was found that due to the occurrence of CA settlement, when the height position of concrete core samples increased from 150 to 750 mm, the chloride permeability increased by 50%, resulting in earlier corrosion initiation of steel bars arranged at a higher position.…”

An experimental and numerical investigation of coarse aggregate settlement in fresh concrete under vibration

“…The settlement of CAs has an adverse impact on the surface appearance, design strength and durability of hardened concrete. This may cause significant problems, such as the decline in mechanical strength, increased shrinkage and cracking, and the reduction of chemical erosion resistance, all of which are detrimental to the performance of reinforced concrete structures [14][15][16][17][18][19][20][21]. However, due to the opacity of concrete, the direct observation of CA settlement with naked eye is impossible.…”