ETDs

This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.

In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.

Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.

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Finite element based microstructural modeling of cementitious composites

Description
This study employs a finite element method based modeling of cementitious composite microstructure to study the effect of presence of inclusions on the stress distribution and the constitutive response of the composite. A randomized periodic microstructure combined with periodic boundary conditions forms the base of the finite element models. Inclusion…

This study employs a finite element method based modeling of cementitious composite microstructure to study the effect of presence of inclusions on the stress distribution and the constitutive response of the composite. A randomized periodic microstructure combined with periodic boundary conditions forms the base of the finite element models. Inclusion properties of quartz and light weight aggregates of size 600μm obtained from literature were made use of to study the effect of their material (including inclusion stiffness, stiffness of interfacial transition zone and matrix stiffening) and geometric properties (volume fraction of inclusion, particle size distribution of inclusion and thickness of the interfacial transition zone) on the composite. Traction-separation relationship was used to incorporate the effect of debonding at the interface of the matrix and the inclusion to study the effect on stress distribution in the microstructure. The stress distributions observed upon conducting a finite element analysis are caused due to the stiffness mismatch in both the quartz and the light weight aggregates as expected. The constitutive response of the composite microstructure is found to be in good conformance with semi-analytical models as well as experimental values. The effect of debonding throws up certain important observations on the stress distributions in the microstructure based on the stress concentrations and relaxations caused by the stiffness of the individual components of the microstructure. The study presented discusses the different micromechanical models employed, their applicability and suitability to correctly predict the composite constitutive response.
ContributorsMaroli, Amit (Author) / Neithalath, Narayanan (Thesis advisor) / Rajan, Subramanium (Committee member) / Mobasher, Barzin (Committee member) / Arizona State University (Publisher)
Created2016
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Effect of Fiber Morphology on Tensile Properties of Polypropylene Cement Composites

Description
The main objective of this study is to investigate the effect of polypropylene fiber morphology on the tensile response of cementitious composites. Two proprietary polypropylene fibers manufactured by BASF – MAC 2200CB, a crimped monofilament macro fiber and MF40, a bundled multi filament polypropylene made up of 500 filaments,40-micron diameter…

The main objective of this study is to investigate the effect of polypropylene fiber morphology on the tensile response of cementitious composites. Two proprietary polypropylene fibers manufactured by BASF – MAC 2200CB, a crimped monofilament macro fiber and MF40, a bundled multi filament polypropylene made up of 500 filaments,40-micron diameter each were compared. The stiff structure and crimped geometry of MAC 2200 CB was studied in comparison with the multifilament MF40, which provide a higher surface area and a bundled fiber effect. Uniaxial tensile tests were performed on individual fibers to study fiber strength and failure pattern at three different gage lengths. The interaction of these 2 fibers with cement matrix was studied under varying strain rate, embedded fiber length and matrix mixes by a series of quassi - static fiber pullout tests. Unidirectional filament wound composite laminates were manufactures with the two fibers and only MF40 woven textiles were used to manufacture MF40 textile reinforced composites. The mechanical behavior of polypropylene fiber and textile reinforced cementitious composites subjected to static tensile loading with the effects of fiber type and dosage, textile weave and dosage, matrix formulations, processing techniques etc. is studied. Evolution of distributed cracking mechanism and local strain fields was documented using digital image correlation (DIC) and correlated with the tensile response and stiffness degradation. VIC 3D-7, commercial software developed by Correlated Solutions, Inc. was used to run the DIC analysis for the tensile tests on laminates. The DIC technique was further used for automated determination of crack density, crack spacing, and characterizing damage evolution.
ContributorsMehere, Himai Ashok (Author) / Mobasher, Barzin (Thesis advisor) / Dharmarajan, Subramaniam (Committee member) / Neithalath, Narayanan (Committee member) / Arizona State University (Publisher)
Created2017