scholarly journals Recovery of Chloride Penetration Resistance of Cement-Based Composites Due to Self-Healing of Cracks

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2501
Author(s):  
Kyung Suk Yoo ◽  
Seung Yup Jang ◽  
Kwang-Myong Lee
Keyword(s):  
Phenomenological Model ◽  
Surface Coating ◽  
Concrete Structures ◽  
Penetration Resistance ◽  
Chloride Penetration ◽  
The Self ◽  
Test Time ◽  
Self Healing ◽  
Diffusion Test ◽  
Chloride Penetration Resistance

This study proposed a method of applying coating on uncracked surfaces of test specimens in the electrical migration–diffusion test for the evaluation of the chloride penetration resistance of cracked cement-based composites. It was shown that, by applying the proposed method, the recovery of the chloride penetration resistance from self-healing of cracks can be evaluated more accurately because the application of surface coating reduces the test time and the error introduced by over-simplification. Based on observations of the self-healing-induced recovery of chloride penetration resistance, a phenomenological model for predicting the progress of crack self-healing in cement-based composites was suggested. This model is expected to evaluate the chloride penetration resistance more accurately in actual concrete structures with cracks.

Influence of Fly Ash as Cement Replacement on Chloride Penetration and Frost Resistance of Recycled Concrete

2011 ◽  
Vol 250-253 ◽  
pp. 1031-1037
Author(s):  
Xiang Hao Wu ◽  
Pan Yuan ◽  
Yan Tao Jiao
Keyword(s):  
Fly Ash ◽  
Frost Resistance ◽  
Penetration Resistance ◽  
Ash Content ◽  
Chloride Penetration ◽  
Recycled Concrete ◽  
Diffusion Test ◽  
Cement Replacement ◽  
Water Test ◽  
Chloride Penetration Resistance

The influence of fly ash as cement replacement on pore structure, chloride penetration and frost resistance of recycled concrete is investigated by evaporable water test, chloride natural diffusion test, and freeze-thawing test. The experimental results indicate that adding fly ash to recycled concrete can decrease its porosity and improve its pore size distribution. Chloride penetration resistance of recycled concrete is enhanced firstly and then reduced with increasing of fly ash content. The best proportion replacing cement with fly ash is 20%. Fly ash content has a certain influence on the frost resistance of recycled concrete, and the frost resistance of recycled concrete only has been improved when the proportion of fly ash replacing cement achieves more than 20%.

Chloride Penetration Resistance of Concrete Structures under Compressive Load

2012 ◽  
Vol 479-481 ◽  
pp. 120-123
Author(s):  
Fu Xiang Jiang ◽  
Yu Tian Wang ◽  
Tie Jun Zhao ◽  
Liang Liang Liu
Keyword(s):  
Mechanical Load ◽  
Concrete Structures ◽  
Compressive Load ◽  
Chloride Concentration ◽  
Penetration Resistance ◽  
Chloride Penetration ◽  
Concrete Durability ◽  
Complex Process ◽  
Apparent Diffusion ◽  
Chloride Penetration Resistance

The mechanism of concrete durability under uniaxial compressive load has been studied through chloride penetration experiments in this contribution. It has been found that there is a good corresponding relationship between chloride penetration resistance of concrete and the applied compressive stress level. With increasing of the applied compressive load, chloride penetration depth and content both decreased firstly. After the compressive load up to a critical level, they began to increase quickly. The apparent diffusion coefficient and chloride concentration at the surface also increase with the same rule. It is shown that chloride penetration of concrete is a complex process. So the effect of mechanical load should be considered as an important factor for prediction of service life of reinforced concrete structures in marine environment.

scholarly journals The Rapid Chloride Migration Test in Assessing the Chloride Penetration Resistance of Normal and Lightweight Concrete

2021 ◽  
Vol 11 (16) ◽  
pp. 7251
Author(s):  
Jorge Pontes ◽  
José Alexandre Bogas ◽  
Sofia Real ◽  
André Silva
Keyword(s):  
Lightweight Concrete ◽  
Chloride Transport ◽  
Penetration Resistance ◽  
Chloride Penetration ◽  
Migration Test ◽  
Simple Method ◽  
Chloride Migration ◽  
Binder Ratio ◽  
Chloride Penetration Resistance ◽  
Water Binder Ratio

Chloride-induced corrosion has been one of the main causes of reinforced concrete deterioration. One of the most used methods in assessing the chloride penetration resistance of concrete is the rapid chloride migration test (RCMT). This is an expeditious and simple method but may not be representative of the chloride transport behaviour of concrete in real environment. Other methods, like immersion (IT) and wetting–drying tests (WDT), allow for a more accurate approach to reality, but are laborious and very time-consuming. This paper aims to analyse the capacity of RCMT in assessing the chloride penetration resistance of common concrete produced with different types of aggregate (normal and lightweight) and paste composition (variable type of binder and water/binder ratio). To this end, the RCMT results were compared with those obtained from the same concretes under long-term IT and WDT. A reasonable correlation between the RCMT and diffusion tests was found, when slow-reactive supplementary materials or porous lightweight aggregates surrounded by weak pastes were not considered. A poorer correlation was found when concrete was exposed under wetting–drying conditions. Nevertheless, the RCMT was able to sort concretes in different classes of chloride penetration resistance under distinct exposure conditions, regardless of the type of aggregate and water/binder ratio.

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