Synopses & Reviews
There is an urgent need for a complete model of concrete systems. One of the most important properties is the transport of moisture into and out of the microstructure and the transport of aggressive chemicals into and through this structure. Although the need is great, present models are incomplete. However, various strategies have been defined and important partial models have been developed. Both computer-based models and mathematical expressions describe transport and deterioration processes. Computer models account for the spatial distribution of phases, but encounter problems of scale, while mathematical expressions are unable to account explicitly for the spatial distribution of phases. Since such properties as permeability depend on the connectivity of pores (i.e. the shape and spatial distribution of pores) in addition to the volume fraction, microstructural models must be developed further. Nevertheless, the 30 contributions to this book present the most up-to-date summary of knowledge about concrete systems and their modelling, covering the scale and resolution of models; spatial distributions; databases and expert systems; transport mechanisms and the major parameters affecting them; and corrosion mechanisms and parameters.
Synopsis
From July 10th through July 13th, 1994, an informal workshop co-organized by RILEM committees 116-PCD and 123-MME was held at Saint-Remy-Ies- Chevreuse, France, and attended by 38 delegates from 16 countries. Twenty-nine papers were presented, converging the general subjects of modelling micro- structures and predicting durability of concrete and other cement-based materials. A short summary follows: G. M. Idom's paper entitled "Modelling Research for Concrete Engineering" serves as an introduction to the workshop, presenting an overview of modelling research with the conelusion that the broad practica1 objective is to produce high-quality concrete. This means that many characteristics, ranging from rheology to alkali-silica reaction, must be modelled. In other words, the system must be understood. Idom's paper sets the stage for papers in two general areas: 1) models and 2) transport properties. After this, abrief survey of the develop- ment of microstructurally-based models is presented. A elose relationship between computer power and speed is suggested. The first group of papers on models covers the subjects of scale and resolution. Most models define and predict characteristics of the pore system, which range in scale from nanometer to millimeter. Various types ofnetworks are proposed in these papers. A good microstructural model must describe the pores and other phases at ascale appropriate to the properties that the model predicts. Also, a good model should be based on fundamental knowledge. In the case of cement-based materials, the important properties may depend on the microstructure, especially the porosity, at several scales.
Table of Contents
Preface. Introduction.
Part I: Modelling Pore Structure. Scale and Resolution of Models. Spatial Distributions. Databases and Expert Systems.
Part II: Transport Mechanisms and Durability. Transport Mechanisms. Major Parameters Affecting Transport Mechanisms. Corrosion Mechanisms and Parameters. Index.