Pozzolanic additions for durability of concrete structures

Pozzolanic additions, used for partial replacement of Portland cement clinker, can improve the strength and durability of concrete structures. Most of pozzolanas used nowadays are residues of industrial processes and their use in concrete technology has the added advantage of improving the sustainability of the cement and concrete industries. For this reason, there is great interest in studying the behaviour of new materials with potential pozzolanic activity. With this regard, several tests have been proposed in the literature to assess different aspects of the pozzolanic behaviour of mineral additions, but these often do not give the same results when used to compare various additions. This paper presents the results of a study aimed at the evaluation of the beneficial effects of different mineral additions (natural pozzolanas, industrial residues and recycled materials such as ground glass) in relation to concrete performance, using different methods of testing. The role of the different additions is analysed, showing lower performance for natural pozzolanas and good behaviour of the finely ground glass. The possibility of using measurement of electrical resistivity as a non-destructive method capable of evaluating the pozzolanic activity of mineral additions at different curing time is discussed.