Carbon nanomaterials enhanced cement-based composites: advances and challenges

Abstract

<jats:title>Abstract</jats:title><jats:p>Carbon nanomaterials, predominantly carbon nanofibers, carbon nanotubes, graphene, graphene nanoplates, graphene oxide and reduced graphene oxide, possess superior chemical, physical and mechanical properties. They have been successfully introduced into ordinary Portland cement to give enhancements in terms of mechanical properties, durability and electrical/thermal conductivity, and to modify the functional properties, converting conventional cement-based materials into stronger, smarter and more durable composites. This paper provides a comprehensive review of the properties of carbon nanomaterials, current developments and novel techniques in carbon nanomaterials enhanced cement-based composites (CN-CBCs). Further study of the applications of CN-CBCs at industrial scale is also discussed.</jats:p>

Ultra-Sensitive Affordable Cementitious Composite with High Mechanical and Microstructural Performances by Hybrid CNT/GNP

“…In fact, incorporating cementitious composite by CNT + GNP leads to increasing mechanical performance due to the bridging mechanism and reducing the porosities. However, an excessive increase of CNMs concentration can cause agglomeration and porosities formation which consequently can decrease flexural and compressive strengths [37]. Despite this decrease, it is noticed that the flexural and compressive strengths values of specimen GC (1.0%) are still greater than the value of plain mortar.…”

The Effect of Carbon Nanotubes on the Flowability, Mechanical, Microstructural and Durability Properties of Cementitious Composite: An Overview

“…Well-designed ultrasonication with sufficient ultrasonication energy can disperse the CNTs uniformly. Insufficient ultrasonication energy cannot disperse the nanomaterials uniformly, while excess sonication energy can cut into smaller fragments [8]. Chemical techniques like surfactants, solvents and functionalization techniques were also used to disperse the CNT in aqueous suspensions.…”

“…Chemical techniques like surfactants, solvents and functionalization techniques were also used to disperse the CNT in aqueous suspensions. Polycarboxylate-based superplasticizer is a commonly used surfactant to disperse CNTs [8]. The chemical CNT dispersion method typically introduces covalent and noncovalent bonds to enhance the wettability of the surface of the nanotubes.…”

“…Du et al [8] summarized the findings of the literature studies and concluded that ultrasonication not only helps to separate the aggregated CNTs but also improve the mechanical properties of CNT-cement-based composites. Similarly, Alrekabi et al [2] and Zou et al [6] stated the importance of ultrasonic energy for improving the mechanical properties of CNTs incorporated in cement-based composites.…”

“…The nanoscale size materials have a strong agglomeration tendency that can effectively influence the mechanical and microstructural performance of cementitious composites [6,7]. Several investigations were carried out utilizing sonication, surfactants to disperse CNTs within composite structures [8][9][10][11]. Without a proper fabrication technique or the direct addition of raw CNTs into a fresh concrete mixture, the conventional concrete mixing process cannot ensure the homogeneous dispersion of CNTs and mechanical performance.…”