Masters Theses

Keywords and Phrases

Bond Strength; Compressive Strength; Dynamic Segregation; Rheology; Self-Consolidating Concrete; Ultrasonic Pulse Velocity

Abstract

"Self-Consolidating Concrete (SCC) is more vulnerable to stability problems as a consequence of its high flowing ability compared to conventional vibrated concrete. Dynamic segregation refers to the tendency of the concrete constituents to separate from the suspended matrix, usually in horizontal direction while being cast into the formwork or due to an impact. Similarly to static segregation, dynamic segregation can affect the homogeneity of SCC. Therefore, it is highly essential to ensure a proper dynamic stability in order to enhance the uniformity of in-situ properties of pre-stressed beams.

In this research project, the effects of SCC mix design parameters are investigated using the T-box test as a method to assess dynamic segregation. Changes in chemical admixture type and content, paste volume, sand-to-total aggregate ratio (S/A), w/cm and the width of the T-box have been evaluated. The results show that dynamic segregation of SCC is dependent on the rheological properties of the concrete, paste volume and S/A.

In a second part, the influence of dynamic segregation on the uniformity of precast, pre-stressed beams is investigated. Six 9 m and three 18 m long beams were produced with SCC. To determine the uniformity of the mixture, a comparative survey across the beam height and along its length was performed. Also, the bond strength of pre-stress strands with SCC was investigated. Results from the UPV and compressive strength demonstrate a variation in the uniformity of the concrete, mainly at the casting point. For the bond strength, with increasing dynamic segregation, the bond between the strand and the concrete at the top 1/3rd of the beam height, relative to the bond in the middle 1/3rd, decreases"--Abstract, page iii.

Advisor(s)

Feys, Dimitri

Committee Member(s)

Khayat, Kamal
Park, Joontaek

Department(s)

Civil, Architectural and Environmental Engineering

Degree Name

M.S. in Civil Engineering

Sponsor(s)

Coreslab Structures

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2016

Pagination

xv, 120 pages

Note about bibliography

Includes bibliographic references (pages 115-119).

Rights

© 2016 Aida M Ley Hernandez, All rights reserved.

Document Type

Thesis - Open Access

File Type

text

Language

English

Library of Congress Subject Headings

Self-consolidating concrete -- Mechanical properties
Self-consolidating concrete -- Additives
Precast concrete -- Testing
Concrete beams -- Testing

Thesis Number

T 10962

Electronic OCLC #

958293678

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