Study of the pozzolanicity of some bricks and clays

Abstract An increasing interest in the pozzolanic activity of bricks with calcium hydrate has been shown recently by researchers dealing with the production of new hydraulic materials for the masonry industry. Furthermore, deteriorated mortars of historic buildings and damaged masonries require repointing, repair or strengthening with mortars and grouts compatible with the existing materials. Admixtures of hydrated lime and crushed bricks also have an acceptable colour from an aesthetic point of view. This paper concerns a systematic research on the pozzolanicity of different bricks and clays. The laboratory tests were based on chemical, mineralogical-petrographical analyses and pozzolanicity tests, applied to measure the capacity of crushed bricks in fixing calcium hydrate (pozzolanicity). Various types of clay, calcinated at different temperatures, are subjected to the pozzolanicity test in order to state the degree of pozzolanicity. The research intends to give guidelines for the production and use of pozzolanic bricks and clays for the preparation of hydraulic mortars and grouts.