Constitutive model for predicting deterioration in concrete

Title: Constitutive model for predicting deterioration in concrete
Author(s): Anthony G. Kerali
Paper category : conference
Book title: 2nd International RILEM Symposium on Advances in Concrete through Science and Engineering
Editor(s): J. Marchand, B. Bissonnette, R. Gagné, M. Jolin and F. Paradis
Print-ISBN: 2-35158-003-6
e-ISBN: 2351580028
Publisher: RILEM Publications SARL
Publication year: 2006
Nb references: 19
Language: English

Abstract: The durability of concrete is one of the most important areas of research interest. Accurate prediction of the durability of concrete under various environmental agents has remained enigmatic due to its complexity. Yet to encourage the production of high quality durable concrete, a sound knowledge of the microstructure, potential deterioration mechanisms, their modes and rates of progression is critical. The objective of this paper is to describe innovative numerically derived constitutive models for predicting the performance and durability of concrete. The interplay between constituent materials, properties and environmental elements are rigorously investigated both mathematically and experimentally. The basic method used involves extensive inspection of defects and classification of various deterioration phenomena occurring in concrete structures, monitoring the progress of deterioration, critically analyzing the mechanisms involved, and then deriving appropriate numerically based equations. Field exposure, accelerated and long-term laboratory tests are used in validating the equations. It was found that depending on its initial properties, concrete deteriorates following three major models, namely; linear, convergent, and exponential. In the first linear deterioration model type, it was established that the rate of deterioration was completely independent of the existing state of degradation, and hence was the most ordinary or non-complicated mode. A typical example in this case is surface property related damage to concrete due to abrasion and impact. In the second cupped deterioration model type, it was noted that the deterioration portions of concrete actually resist deterioration agents. Because of this factor, the initially high rate of deterioration is gradually reduced over time. Typical examples examined include carbonation and creep in concrete which affect its bulk properties. In the third and last convex deterioration model category, it was established that the rate of deterioration was highly dependent on the prevailing state of degradation, and hence the greater the deterioration, the faster the rate of degradation. A typical example in this case is the corrosion of reinforcement in concrete structures. Constants used in the predictive equations were trained, and evaluated to the extent that experimental outputs could bear them out in each case. It can be safely concluded that the use of constitutive models and the application of these findings are likely to be of worldwide significance in understanding the deterioration of concrete. Further evaluation of these numerical equations using simulative techniques should now form the next phase for similar research.

Keywords: predictive equations, modeling, durability, deterioration, properties, concrete

Online publication: 2006-08-02
Classification: 3.1 Theme 1: Numerical Models: from Microstructure to Transport Properties and Durability
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2351580028.030