Creep and shrinkage prediction models for concrete water retaining structures in South Africa
Date
2010-12
Authors
Mucambe, Edson Silva David
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : University of Stellenbosch
Abstract
ENGLISH ABSTRACT: Concrete water retaining structures (WRS) in South Africa are under scrutiny due to
the numerous durability problems that they have experienced lately; despite the
efforts by local and national authorities in conserving these structures. At the heart of
these problems are the creep and shrinkage phenomena. While shrinkage is the
reduction of concrete volume with time, creep is defined as the time-dependent
increase of concrete strain under constant or controlled stress. Both phenomena are
affected by conditions to which WRS are exposed hence their accurate prediction is
required.
Numerical models have been developed to calculate the extent to which concrete
creeps or shrinks over time. The objective of this thesis is to identify which of these
models is better equipped to be used in South African WRS design. This is achieved
through a systematic method that involves an investigation into the contents of these
models and a statistical comparison of model calculations to WRS representative
data.
In partnership with reputable universities, a pioneer experimental creep and
shrinkage data base is created in this project from which the WRS related data is
selected. While investigating the contents of the numerical models, their applicability
to South African WRS is identified and the integrity of model contents is assessed.
Indeed, a few irregularities are found in the process and are presented in this thesis.
The model calculations are statistically compared to data in the form of individual
experiments as well as in the form of groups of experiments with similar concretes to
find the ideal prediction model for different types of concretes as well.
Also pioneered in this project is a weighted criteria and point system in which the
findings of the model content assessment and statistical evaluations are
incorporated. It is based on this system that conclusions are drawn and the most
suitable prediction model for WRS design in South Africa is selected.
Description
Thesis (MScEng (Civil Engineering))--University of Stellenbosch, 2010.
Keywords
Concrete -- Creep, Concrete -- Expansion and contraction, Concrete water retaining structures, Dissertations -- Civil engineering, Theses -- Civil engineering