Doctoral Dissertations

Abstract

"The advantages of using shrinkage mitigating strategies to reduce shrinkage and mitigate cracking of concrete is well documented. However, the benefits and drawbacks of employing multiple strategies have not been explored. The main objective of this study is to provide insights into the mechanisms of using multiple strategies to enhance shrinkage and cracking resistance to promote the properties of high-performance cementitious composites (HPC) designated for infrastructural construction, repair, and 3D printing applications. HPC mixtures were prepared with steel and synthetic macro and microfibers, expansive agent (EA), and shrinkage reducing admixture (SRA) coupled with various curing methods e.g., internal curing using saturated lightweight sand (LWS) and superabsorbent polymer (SAP), and external curing. A multi-scale investigation employing these strategies was conducted to determine their effects on rheology, key mechanical properties, fiber-matrix bonding, shrinkage, microstructural characteristics, and durability. Test results indicate that the combined strategies at small contents are effective in reducing shrinkage. The use of shrinkage mitigating strategies at relatively high content can impair microstructure. Incorporating hybrid steel fibers and EA with extended moist curing can induce internal prestressing and enhance flexural strength. Using hybrid synthetic fibers, EA, and SRA in self-consolidating concrete can enhance flexural strength and cracking resistance of repaired beams and provide superior bonding to the substrate. Incorporating EA with either SAP or SRA can produce high strength cement paste with zero autogenous shrinkage. Such materials can be flowable and thixotropic to promote pumpability and buildability for 3D printing"--Abstract, p. v

Advisor(s)

Khayat, Kamal

Committee Member(s)

Feys, Dimitri
Kumar, Aditya
Ma, Hongyan
Myers, John J.

Department(s)

Civil, Architectural and Environmental Engineering

Degree Name

Ph. D. in Civil Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2022

Pagination

xxvi, 420 pages

Note about bibliography

Includes_bibliographical_references_(pages 409-419)

Rights

© 2022 Kamran Aghaee, All Rights Reserved

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 12271

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