Effect of Multi-Walled Carbon Nanotubes on Improving the Toughness of Reactive Powder Concrete

Jintao Liu,Hang Jin,Cheng Wang,Xin Zhao

doi:10.3390/ma12162625

Abstract

Multi-walled carbon nanotubes (MWCNTs) have great potential to improve the strength and microstructure of traditional cement-based materials. In this research, different aspect ratios of MWCNTs (F-type and L-type) were dispersed into water using surfactants, and then incorporated into reactive powder concrete (RPC) for improving mechanical and microstructure properties. With the addition of 0.025 wt.% F-MWCNTs, the 28 days compressive strength and initial-cracking flexural strength increased by 7.2% and 36%, respectively. Moreover, the first-cracking tensile strengths of the composites containing L-MWCNTs were improved by 16%. Energy absorption capability indices were formulated based on tensile load–displacement curves, and results showed that the energy absorption capabilities of RPC at initial cracking improved as a result of the incorporation of MWCNTs. Furthermore, microscopic analysis indicated that MWCNTs decelerate crack development at the nanoscale and improve the initial-cracking tensile strength of RPC.

Highlights

Reactive powder concrete (RPC) with extremely high strength and durability was developed by Pierre at the end of the last century and has been widely used in long-span bridges, concrete penstock and containment structures due to its excellent performance [1]
The mid-span displacement was recorded with Linear variable differential transformer sensors (LVDT)
With the addition of 0.025 wt.% L-Multi-walled carbon nanotubes (MWCNTs), the initial cracking strength and ultimate tensile strength increased by 16%

Summary

Introduction

Reactive powder concrete (RPC) with extremely high strength and durability was developed by Pierre at the end of the last century and has been widely used in long-span bridges, concrete penstock and containment structures due to its excellent performance [1]. The fracture energy of RPC is up to 40000 J/m2 , which is 250 times that of ordinary concrete [2]. According to Zheng et al [5], the tensile strength of RPC without steel-fiber reinforcement was only about 5.7 MPa, while it was. The dynamic tensile behavior of reactive powder concrete was investigated. Results showed that the static tensile strength of RPC was 5.0 MPa, and RPC’s dynamic tensile stress rapidly increased with an increased strain rate [6]

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