COMPARISON OF FROST DEICING SALT DAMAGE MECHANISMS IN FIELD AND LABORATORY CONDITIONS Comparison of frost damage mechanisms

摘要

In spite of progress in concrete technology in the recent years severe damages and high repair costs caused by frost deicing salt attack are still very frequent. In future the situation will probably get much worse, because of the growing number of cement addition and admixture types and the ecological need for using alternative or recycled aggregates on one hand and the lack of knowledge of damage mechanisms, the relation between test results and on-site behaviour of concrete on the other. The scope of the presented investigations was to study the behaviour of concrete in practise and in laboratory tests. First, the temperature profiles within concrete on-site (bridge) and in laboratory tests (Boras, CDF) are compared. The freezing of pore water was studied by means of ultrasonic pulse transit time measurement. The deterioration of the concrete is studied by means of confocal microscopy.