Discussing the durability assessment of cement mortars - A contribution for a prediction model.

Abstract

The aim of this paper is to present a discussion on the assessment of the durability of industrial cement mortars, based on two experimental research works carried out at the Building Physics Laboratory, Faculty of Engineering, University of Porto, Portugal. The service life prediction of any construction material is not an easy task. The researchers must choose between several different approaches which one with its advantages and its limitations. While in real buildings, with in-use conditions, the material or component is subject to changeable actions in an environment where the great majority of the degradation agents is not controllabed by the man, in laboratory, we can choose to expose the material to artificial and controlled conditions, using chambers of accelerated ageing. The main difficulty of this last type of tests consists in the interpretation of the results, in what concerns their correspondence to real time. Researchers on durability have been discussing this problem since a long time: how to get a valuable correlation between the results of accelerated ageing tests and the one issued form natural exposure? In this paper, we present a discussion on this subject based on the above mentioned studies, concerning the performance over time of two different types of industrial cement mortars exposed to accelerated ageing tests and also to natural ageing. The main advances and the main difficulties in implementing a service life prediction model will be identified. Finally, we will discuss suitable strategies for the future development of this approach. KEYWORDS: Durability, performance, accelerated ageing tests, natural ageing, prediction model