Autogenous Healing of Cracked Mortar Using Modified Steady-State Migration Test against Chloride Penetration

Fahad Ul Rehman Abro,Zain Ul-Abdin,Tariq Ali,Noor Ahmed Memon,Zaheer Ahmed,Ali Raza Lashari,Abdul Salam Buller

doi:10.3390/su13179519

Abstract

Concrete is a popular building material all over the world, but because of different physiochemical processes, it is susceptible to crack development. One of the primary deterioration processes of reinforced concrete buildings is corrosion of steel bars within the concrete through these cracks. In this regard, a self-healing technique for crack repair would be the best solution to reduce the penetration of chloride ions inside concrete mass. In this study, a rapid chloride migration (RCM) test was conducted to determine the self-healing capacity of cracked mortar. With the help of the RCM test, the steady-state migration coefficient of cracked and uncracked specimens incorporating expansive and crystalline admixtures was calculated. Based on the rate of change of the chloride ion concentrations in the steady-state condition, the migration coefficient was calculated. Furthermore, bulk electrical conductivity tests were also conducted before and after the migration test to understand the self-healing behavior. It was evident from the test results that the self-healing of cracks was helpful to reduce the penetration of chloride ions and that it enhanced the ability of cracked mortar to restrict the chloride ingress. Using this test method, the self-healing capacity of the new self-healing technologies can be evaluated. The RCM test can be an acceptable technique to assess the self-healing ability of cement-based materials in a very short period, and the self-healing capacity can be characterized in terms of the decrease of chloride migration coefficients.

Highlights

Concrete is a global material used for construction projects because it is a relatively cheap material, and it is easy to use in construction
0.2 mm cracked; in 3rd cycle, the last two specimens were 0.3 mm cracked while the while the first two were uncracked and 0.2 mm cracked; and in last cycle, uncracked, 0.2 first two were uncracked and 0.2 mm cracked; and in last cycle, uncracked, 0.2 mm, 0.3 mm, mm, 0.3 mm, and 0.4 mm cracked specimens were used for the migration test, and the and 0.4 mm cracked specimens were used for the migration test, and the same were tested same were tested at 28, 56, and 120-day healing
The self-healing capacity of cracked mortar containing crystal(c) SH6; (d) SH8.line admixtures (CA) and expansive agents was investigated against the penetration of chloride ions with the help of a modified steady-state migration test

Summary

Introduction

Concrete is a global material used for construction projects because it is a relatively cheap material, and it is easy to use in construction. As a matter of fact, is vulnerable to cracking, and these cracks generally develop in most concrete members considering the service life of the concrete These cracks can provide a quick way for chloride ions and carbonation to penetrate through the structure, which can lead to reinforcement corrosion causing failure of the structure [1]. To increase the service life of concrete, it is essential that these cracks may be repaired as quickly as possible to prevent harmful agents [2]. These cracks tend to spread, and new cracks frequently appear even after repair, resulting in a cycle of the ongoing degradation of concrete structure durability and a reduction in service life [3].

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