Civil Engineering ETDs

Publication Date

2-14-2014

Abstract

Polymer Concrete (PC) is one of three types of polymers in concrete that was introduced in the 1950s and has had many successful civil engineering applications. PC is recognized in the industry as a mix of aggregate and polymer resin with no Portland cement. PC has been favoured over conventional Portland cement concrete when special characteristics such as low permeability, high adhesion, and/or high durability for service in aggressive (e.g. chemical) environments are required. In this research, a new generation of PC incorporating Multi-Walled Carbon Nano-Tubes (MWCNTs) was produced and its mechanical properties were investigated. Four mixes of PC with 0.0 (neat), 0.5, 1.0, and 1.5% MWCNTs, respectively, were prepared using low modulus polysulfide epoxy mixed with fine and coarse aggregate, or fine aggregate only. PC incorporated fine and coarse aggregate in the mixes, while PC overlays incorporated fine aggregate only. Test protocols included investigating the mechanical properties of PC, examining the bond strength of the PC overlays with steel and microstructural characterization of epoxy-MWCNTs nanocomposite. iv Investigation of the static mechanical properties of PC included identifying the effect of MWCNTs on compressive strength, flexural strength, and shear strength, as well as creep behavior of PC under axial sustained loads. We also examined the dynamic response of PC using Charpy impact and low-velocity impact tests. Furthermore, the bond strength between steel plates and PC overlays was evaluated. This included performing the pull-off and slant shear tests. Moreover, four-point bending fatigue test was performed to examine the fatigue strength of PC overlays under cyclic traffic loads. Finally, microstructural and thermal stability of epoxy incorporating MWCNTs was evaluated using Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Thermal Gravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC). The test results emphasized that MWCNTs altered the microstructure of the epoxy and increased the crosslinking between epoxy groups significantly. This lead to improving the mechanical properties of PC and PC overlays. Significant improvements were also observed in bond strength with steel, impact strength and fatigue strength. It is believed that using MWCNTs can produce a new generation of PC with much improved performance for bridge deck overlays and for panels used for blast protection.

Keywords

Polymer Concrete, Carbon Nanotubes

Sponsors

STC.UNM and Department of Energy

Document Type

Thesis

Language

English

Degree Name

Civil Engineering

Level of Degree

Masters

Department Name

Civil Engineering

First Committee Member (Chair)

Maji, Arup

Second Committee Member

Stormont, John

Third Committee Member

Fowler, David

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