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Low-cost, ubiquitous biomolecule as next generation, sustainable admixture to enhance the performance of ordinary portland cement-based concretes

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dc.contributorSong, Wei
dc.contributorAaleti, Sriram
dc.contributorAmirkhanian, Armen
dc.contributorZhao, Chao
dc.contributor.advisorWang, Jialai
dc.contributor.authorFang, Yi
dc.contributor.otherUniversity of Alabama Tuscaloosa
dc.date.accessioned2021-07-07T14:36:46Z
dc.date.available2021-07-07T14:36:46Z
dc.date.issued2021
dc.descriptionElectronic Thesis or Dissertationen_US
dc.description.abstractThe production of ordinary Portland cement (OPC) is highly energy-intensive and responsible for approximately 6% of anthropogenic greenhouse gas emissions. To reduce the carbon footprint of OPC based concrete, this research proposes to use a low-cost, ubiquitous, naturally occurring compound, tannic acid (TA) as a small-dose additive to significantly enhance the strength of OPC based concrete.This study is inspired by biosystems’ protein-based materials, which generally exhibit superior strength and toughness owing to their hierarchical structures via hydrogen-bonding assembly. With abundant reactive terminal phenolic hydroxyl groups, TA has an ability to complex or cross-link macromolecules sites through multiple interactions. Thus, TA can be used to complex or cross-link hydration products of cement at multi-binding sites so that the strength and durability of concrete can be significantly improved. A comprehensive research plan has been carried out to evaluate the potential of TA on performance enhancement of OPC-based concrete, understand how TA modifies the hydration of cement, mitigate the retardation of TA on cement’s hydration, and evaluate application potentials in concretes with SCMs. Experimental studies show that TA can strongly retard the hydration of cement and alite due to its ability to bind to various particles and chelate with calcium ions, causing less calcium hydroxide produced by the hydration. The strong interaction between the TA and hydration products leads to morphology change of the hydration products and generates nanoparticles at early age. Furthermore, addition of TA can significantly densify the nanostructure of cement pastes. Particularly, capillary pores smaller than 70nm are drastically reduced by TA. This finding is not only explaining why TA can enhance the micromechanical properties of concrete, but also opening a new approach to tune the nanoscale pores in concrete. Besides, a pre-hydration method is proposed and verified to mitigate the retarding effect of TA for widely adopted in practical application. Significant strength improvement at late age can be achieved by pre-hydration with TA without losing of strength at early age. TA is also successfully used in mortars with silica fume to achieve over 30% strength improvement, suggesting its huge potential to reduce the carbon footprint of concrete.en_US
dc.format.extent211 p.
dc.format.mediumelectronic
dc.format.mimetypeapplication/pdf
dc.identifier.otheru0015_0000001_0003782
dc.identifier.otherFang_alatus_0004D_14468
dc.identifier.urihttp://ir.ua.edu/handle/123456789/7861
dc.languageEnglish
dc.language.isoen_US
dc.publisherUniversity of Alabama Libraries
dc.relation.hasversionborn digital
dc.relation.ispartofThe University of Alabama Electronic Theses and Dissertations
dc.relation.ispartofThe University of Alabama Libraries Digital Collections
dc.rightsAll rights reserved by the author unless otherwise indicated.en_US
dc.subjectCivil engineering
dc.subjectMaterials science
dc.titleLow-cost, ubiquitous biomolecule as next generation, sustainable admixture to enhance the performance of ordinary portland cement-based concretesen_US
dc.typethesis
dc.typetext
etdms.degree.departmentUniversity of Alabama. Department of Civil, Construction, and Environmental Engineering
etdms.degree.disciplineCivil, Construction & Environmental Engineering
etdms.degree.grantorThe University of Alabama
etdms.degree.leveldoctoral
etdms.degree.namePh.D.

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