Masters Theses

Amos Wamweya

Abstract

"This study is a GPR-based assessment of three bridge decks, two with a hot bituminous wearing surface and one with a bare concrete slab. The primary objectives of this study were: 1) to assess the integrity of the three bridge decks using a 1.5 GHz ground-coupled GPR antenna, and 2) to evaluate the utility of the 1.5 GHz ground-coupled antenna for bridge deck investigations. Core control (chloride ion concentration data and core integrity data) and visual inspection were used as interpretive constraint. The acquired GPR data were interpreted, and two plan view maps were generated. One depicts the magnitude of the reflections from the uppermost mat of rebar, and the second shows the arrival time of these reflections. Analysis of the GPR data and core control indicates that the magnitude of the reflected GPR signal from the uppermost mat of rebar is a direct function of concrete integrity. Higher magnitude reflections indicate higher quality concrete. To a lesser extent, the arrival time of the reflected energy is also indicative of concrete quality. Faster arrival times generally indicate higher quality concrete. Exceptions to this rule occur where the depth to the top layer of rebar varies. In this study, relative reflection amplitudes of less than 3000 on the bare concrete bridge and less than 5000 on the bituminous surface bridges indicate severe deterioration. Core control data was interpreted based on chloride ion corrosion threshold. Corrosion of rebar occurs once chloride ions content adjacent to the rebar reaches a threshold of approximately 0.033% to 0.04% by weight of concrete (or 330 ppm to 400 ppm). The GPR data correlates well with the core control, indicating that the 1.5 GHz antenna is an effective tool for assessing the condition of bridge decks"--Abstract, page iii.

Advisor(s)

Anderson, Neil L. (Neil Lennart), 1954-

Committee Member(s)

Abdel Salam, Mohamed G.
Maerz, Norbert H.

Department(s)

Geosciences and Geological and Petroleum Engineering

Degree Name

M.S. in Geological Engineering

Publisher

Missouri University of Science and Technology

Publication Date

2009

Pagination

xi, 108 pages

Note about bibliography

Includes bibliographical references (pages 104-107).

Rights

© 2009 Amos Wamweya, All rights reserved.

Document Type

Thesis - Open Access

File Type

text

Language

English

Subject Headings

Ground penetrating radarBridges -- Floors -- Inspection

Thesis Number

T 9504

Print OCLC #

436168014

Electronic OCLC #

309295778

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