Abstract

Underwater structures represent a significant portion of concrete works worldwide. The utilization of various underwater concrete techniques has indeed minimized the use of costly dewatering processes. Such techniques include the use of special· equipment such as trernie concrete and preplaced aggregate technique. The incorporation of antiwashout admixtures has evolved as a method to minimize the washout of cement and fine particles. As for today, there exists relatively limited information regarding different underwater concreting techniques to facilitate feasible and adequate selection of appropriate methods. This work comprises a survey study and an experimental work to evaluate the impact of using the available current underwater concreting techniques. The impact of using tremie method (with some modifications) and antiwashout admixtures (two types and dosages) in underwater concrete placed at various water depths and in air, is included. (Unsuccessful attempts have been carried out to explore the possibility for preplaced aggregate underwater placement.) The workability, air content, unit weight and washout performance of fresh concrete were evaluated for thirty-six mixtures prepared. The hardened density, compressive and flexural strength of hardened concrete have also been assessed. Moreover, the corrosion of reinforcing steel was evaluated through the use of beams exposed to brine aggressive environment. Finally, a preliminary cost analysis was conducted to compare the costs of the stated underwater concreting methods. The results of this work reveal that the underwater construction technique, water depth and alternating mix proportions significantly affect the quality of the produced concrete. The workability and amount of washout of antiwashout concrete is inferior as compared to their conjugate mixtures made with no antiwashout admixtures. The hardened density of underwater concrete decreases with an increase in water depth. Results also indicate that ttemie concrete can yield better strength performance than antiwashout concrete. However, results show that antiwashout admixture concrete can have several technical, as well as economic merits.

School

School of Sciences and Engineering

Department

Construction Engineering Department

Date of Award

2-1-2002

Online Submission Date

1-1-2001

First Advisor

Mohamed Nagib Abou-Zeid

Committee Member 1

Mohamed Nagib Abou-Zeid

Committee Member 2

Amr Ezzat Salama

Committee Member 3

Safwan A. Khedr

Document Type

Thesis

Extent

197 leaves

Library of Congress Subject Heading 1

Underwater concrete construction

Rights

The American University in Cairo grants authors of theses and dissertations a maximum embargo period of two years from the date of submission, upon request. After the embargo elapses, these documents are made available publicly. If you are the author of this thesis or dissertation, and would like to request an exceptional extension of the embargo period, please write to thesisadmin@aucegypt.edu

Call Number

Thesis 2001/73

Location

mmbk

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