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Investigation of Delayed Ettringite Formation Damage Process Using Simultaneous Neutron and X-Ray Tomography
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| 자료유형 | 학위논문 |
|---|---|
| 서명/저자사항 | Investigation of Delayed Ettringite Formation Damage Process Using Simultaneous Neutron and X-Ray Tomography. |
| 개인저자 | Feuze Lekem, Serge Alain. |
| 단체저자명 | University of Maryland, College Park. Civil Engineering. |
| 발행사항 | [S.l.]: University of Maryland, College Park., 2019. |
| 발행사항 | Ann Arbor: ProQuest Dissertations & Theses, 2019. |
| 형태사항 | 226 p. |
| 기본자료 저록 | Dissertations Abstracts International 81-05B. Dissertation Abstract International |
| ISBN | 9781687911131 |
| 학위논문주기 | Thesis (Ph.D.)--University of Maryland, College Park, 2019. |
| 일반주기 |
Source: Dissertations Abstracts International, Volume: 81-05, Section: B.
Advisor: Amde, Amde M. |
| 이용제한사항 | This item must not be sold to any third party vendors. |
| 요약 | Delayed ettringite formation (DEF) is a significant deterioration process in concrete which involves the growth of ettringite [Ca6Al2(SO4)3(OH)12 쨌26H2O] crystals leading to cracking and reduction of compressive strength. Conditions leading to DEF are well known and include among others cement chemistry, presence of humidity, heat curing of concrete structures, and the presence of cracks. The mechanisms and kinetics by which deterioration occur is still not well understood despite numerous investigations. Understanding the mechanism and kinetics of concrete deterioration due to DEF is important in order to prevent such costly deterioration and to improve concrete durability.In this research, concrete specimens were prepared with type III Portland cement and under different conditions that were designed to either promote or inhibit DEF. These consisted of a control set, a set subjected to a heat cycle and a third set made with elevated potassium content of 1.72% and also thermally cycled. They were tested periodically up to 380 days by conventional methods such as expansion and weight change measurements and compressive strength testing. Scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDAX) confirmed the presence and the morphology of ettringite in voids at different ages. Simultaneous neutron and X-ray tomography, a new nondestructive microscopic method was used to scan the specimens at regular intervals in order to assess the feasibility of the method in monitoring the progress and characterizing DEF induced damages.The linear regression analysis of the correlation of expansion with weight change data revealed that expansion and deterioration process occurred in three distinct successive stages. In the first stage, the ettringite fills the pores with little or no expansion |
| 일반주제명 | Civil engineering. Materials science. |
| 언어 | 영어 |
| 바로가기 | 
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