The Effect of the Addition of Graphene Nanoplatelets on the Selected Properties of Cementitious Composites

Jin Qin,Yanhua Guan,Zheng Wang,Zhi Ge,Renjuan Sun,Hongzhi Zhang

doi:10.3389/fbuil.2021.673346

Abstract

The aim of the current study is to investigate the properties of graphene nanoplatelets-cementitious composites in a consistent sense. The influence of the addition of 2D graphene nanoplatelets (GNPs) on the workability, setting time, flowability, strengths and piezoresistive properties were studied. The dosage of the GNPs is 0 0.05, 0.1, 0.3, 0.5, 0.7, and 1.0 wt% of the binder material. PVP type surfactant was used to disperse GNPs. The experimental results showed that the addition of GNPs increases the water requirement for normal consistency and decreases the flowability. A small amount of GNPs (0.05 wt%) can facilitate the setting. When the dosage of GNPs is above 0.1 wt%, it leads to the delay of the setting time. In terms of the strengths, the addition of GNPs can considerably promote the flexural strength, while the compressive strength is slightly decreased until 28 days. A pre-treatment procedure consisting of drying specimens at 105°C for 1 day can be regarded as a proper way to enhance the piezoresistive properties of the GNPs-mortar. Piezoresistive properties under two different cyclical loading schemes were measured using the GNPs-mortar with 1 wt% GNPs. It has been shown that the average resistance change rate increases with the amplitude increasing and a reduction is observed for the sustained cyclical loading condition. In the end, the influence of the microcracks on the piezoresistive properties was investigated. This study will contribute to future developments of cementitious composites incorporating GNPs for a variety of applications.

Highlights

Concrete structures face dynamic loading from different sources, such as high-speed wind and earthquakes
The findings of this study provide insights into properties of graphene nanoplatelets (GNPs) cement composites in a consistent way and reveal their practical implications
Based on the results and analysis, the following conclusions were drawn: The addition of GNPs has a negative effect on the workability and delays the setting time of the GNPs-cement composites

Summary

Introduction

Concrete structures face dynamic loading from different sources, such as high-speed wind and earthquakes. The dynamic loads may cause severe vibrations and large deflections, resulting in cracks in the concrete. The cracks threat the safety of the structures, and bring discomfort to the residents. In order to reduce failure risk or maintenance costs, the real-time monitoring and evaluation of concrete structures have generated considerable research efforts. It has been reported that these methods exhibit durability issues and require expensive external facilities (Chen and Chung, 1996). Nanoplatelets-Cementitious Composites development of piezoresistive cement-based materials have shed much light on the transformation sensing technology applicable to concrete structures (Shi and Chung, 1999; Liu et al, 2018; Yoo et al, 2018)

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