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Date of Award

2014

Document Type

Master's Thesis

Degree Name

Master of Science in Civil Engineering (MS)

College, School or Department Name

Department of Civil and Environmental Engineering

First Advisor

Qingli Dai

Abstract

This study focuses on the effects of internal curing technique on ITZ transport properties of cement mortar using image techniques and computational method. The transport properties including permeability, pore connectivity and porosity were simulated based on 3D digital samples. Permeability solver code developed in National Institute of Standards and Technology was applied to calculate these properties based on Stokes equation and Darcy's law. The formulation of governing equation and finite-difference based numerical scheme were explained in details. The code was first applied on a microscale cement paste digital sample from transmission X-ray microscope (TXM). The comparison between computed permeability, predicted permeability and existing experiment data proved that the simulation method is capable to yield acceptable results within a reasonable range. After this study, two types of mortar specimens were prepared with saturated lightweight aggregates (with internal curing) and regular sands (without internal curing). The scanning electron microscope (SEM) techniques were applied to characterize the 2D ITZ microstructure of mortar specimens. The 3D image reconstruction techniques were used to generate the 3D ITZ microstructure base on 2D SEM images. The simulation code was applied on these generated 3D digital samples. The characterization and simulation results indicate that the permeability of ITZ section in internal curing samples was reduced due to less percolated porosity and characteristic pore sizes, compared with the samples without internal curing.

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