Experimental Investigation on Effect of Carbon Nanotubes and Carbon Fibres on the Behavior of Plain Cement Mortar Composite Round Bars under Direct Tension

A M Hunashyal,Sagar V Tippa,N R Banapurmath,S S Quadri

doi:10.5402/2011/856849

A M Hunashyal, Sagar V Tippa + Show 2 more

Open Access

https://doi.org/10.5402/2011/856849

Copy DOI

Journal: ISRN Nanotechnology	Publication Date: Sep 11, 2011
Citations: 56	License type: CC BY 3.0

Affiliation: KLE Technological University

Abstract

This paper investigates the behavior of reinforced cement mortar composite round bars with multiwalled carbon nanotubes (MWCNTs) and carbon fibers (CFs). The percentage of CFs was fixed at 2.25 wt% of cement, while the percentage of MWCNTs was fixed at 0.5, by wt% of cement. Dispersion of both MWCNTs and CFs was carried out using ultrasonic energy method. Composite round bars were tested under direct tension in order to evaluate their mechanical properties such as ultimate load, deflection criteria, and stress-strain behavior. These results were then compared with the results of plain cement control round bars. From the study, it is shown that the load carrying capacity of composite bars under direct tension is substantially higher than the plain controlled bar.

Highlights

Concrete is not normally designed to resist direct tension, the knowledge of tensile strength of concrete is of value in estimating the load under which cracking will develop [1]
Bars with random distribution of carbon fibers (2.25%) and random distribution of multi walled carbon nanotubes, that is, 0.5% by the weight of cement increase the tensile strength by 53.28% compared to plain bars.Bars with random distribution of multiwalled carbon nanotubes, that is, 0.5% by the weight of cement, increase tensile strength by 19%
The study mainly focuses on the utilization of multiwalled carbon nanotubes (MWCNTs) and carbon fibers (CFs) in cement-based matrix for direct tension tests leading to the development of a new material for structural applications

Summary

Introduction

Concrete is not normally designed to resist direct tension, the knowledge of tensile strength of concrete is of value in estimating the load under which cracking will develop [1]. Cementitious materials are typically characterized as quasibrittle materials, with low tensile strength and low strain capacity, and affect long-term durability of structures These days, discrete short fibers are widely used to control cracking in fiber-reinforced concrete (FRC) [2]. A new material which exhibits enhanced tensile strength, young’s modulus and improved early a strain capacity can be created as found in the literature [10]. Carbon nanotubes have the potential to enhance the strength, effectively hinder crack propagation in cement composites, and act as nucleating agents [4]. The research work carried out on use of carbon fibers and CNTs in beams has reported that both CF and CNTs act as good reinforcing materials and strengthen the composite beams both at macro- and microlevels in cement-based composite beams [18]

Experimental Programme

Results and Discussion

Conclusions