Pozzolanic properties of brick powders and their effect on the properties of modified lime mortars

Abstract

The article deals with the evaluation of six brick dusts which were characterized regarding their chemical and mineralogical composition, amorphous phase content, granulometry and specific surface area. The pozzolanic activity was determined by the modified Chapelle test. The analysed brick dusts were used to prepare modified lime mortars in which lime hydrate was replaced by 50% of brick dust. The flexural and compressive strengths of the mortars were determined and pozzolanic activity was calculated from the compressive strengths. The pozzolanic activity of brick dusts is dependent in particular on their amorphous phase content, particle size distribution and specific surface area. Pozzolanic activity increases with increasing amorphous phase content in the brick dusts. Pozzolanic activity has an effect on the strength of modified lime mortars. The higher is the pozzolanic activity value of the added brick dust the higher are the initial and long term strengths of the modified lime mortars.