Influence of Cracking on the Durability of Reinforced Concrete with Carbon Nanotubes

Jose Alexandre Bogas,Tomás Diniz,Hawreen Hasan Ahmed

doi:10.3390/app11041672

Jose Alexandre Bogas, Tomás Diniz + Show 1 more

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https://doi.org/10.3390/app11041672

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Abstract

This study focuses on the influence of natural and artificially induced cracks on the durability of concrete reinforced with carbon nanotubes (CNT). Pre-cracked concrete mixes, unreinforced or reinforced with 0.1% CNT, are characterized in terms of capillary absorption, carbonation, and chloride penetration resistance, and compared to the uncracked reference concrete. The mechanical strength and durability properties were improved in uncracked CNT-reinforced concrete, without significantly affecting its density and workability. The efficiency of CNT was higher when the concrete was previously subjected to drying conditions. For all tested properties, the incorporation of CNT was effective in reducing the influence of artificial and natural cracks on concrete durability. The main contribution of CNT occurred in the crack surrounding region. Depending on the analyzed property and cracking conditions, the significant reduction of durability in cracked concrete may be 10–30% attenuated when CNT is incorporated. The effect was more pronounced in mechanically induced natural cracks, where CNT may better participate in their vicinity.

Highlights

IntroductionPublisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
The durability of cracked concrete reinforced with carbon nanotubes (CNT) was analyzed by means of capillary absorption, carbonation, and chloride penetration tests
10%), while the properties measured in concrete previously subjected to drying conditions, namely capillary absorption and carbonation resistance, were improved up to 18% and 27%, respectively

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Concrete is a quasi-brittle material highly prone to crack formation throughout its service life [1,2]. The reasons behind crack appearance in concrete include poor design, mechanical actions, hygrothermal changes, shrinkage, and others [3,4]. Cracks tend to form in concrete when the internal tensile stresses surpass its optimum tensile strength

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