Author: Hamdi Celik Ozyildirim Publisher: ISBN: Category : Concrete Languages : en Pages : 28
Book Description
Many concrete structures are not providing the expected service life. Repairs are costly, cause inconvenience to motorists, and raise safety concerns. The durability of concrete depends on, among other things, the ability to resist the penetration of harmful solutions, e.g., chlorides. Recently, pozzolanic materials have been widely used to decrease the permeability of concretes. In this study, the permeability of concretes containing portland cement alone or portland cement with a pozzolan (fly ash, silica fume) or a slag was determined by either the rapid permeability test (AASHTO T 277) or the ponding test (AASHTO T 259). Concretes were tested with either test to determine the reduction in permeability with time. Results show that both tests indicate the permeability of concretes. The rapid permeability test is more convenient and relatively faster than the ponding test. Permeability decreases with time, and the addition of pozzolans or slag is very effective in decreasing permeability.
Author: H. Jennings Publisher: Springer Science & Business Media ISBN: 9401586462 Category : Technology & Engineering Languages : en Pages : 554
Book Description
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.
Author: H. Hilsdorf Publisher: CRC Press ISBN: 0203626672 Category : Architecture Languages : en Pages : 226
Book Description
This is a state-of-the-art report prepared by RILEM Technical Committee 116-PCD and is an authoritative, international review of the subject and is an essential reference source for engineers and technologists. Performance Criteria for Concrete Durability explains key aspects of concrete durability, and the relationships between transport mechanisms and concrete durability characteristics. It reviews test methods for measuring permeability in the laboratory and on site, and discusses the many factors which influence the durability of concrete to carbonation, chlorides, abrasion etc.
Author: Hamdi Celik Ozyildirim
Author: Joseph F. Lamond
Author: National Research Council (U.S.). Transportation Research Board
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Author: Paul Klieger
Author: H. Jennings
Author: 
Author: 
Author: H. Hilsdorf
Author: Jing Si Huo