Abstract The addition of pozzolans has a potentially important role in the cement industry since using waste from other industries has important environmental benefits, including reduced CO2 emissions from cement production. This study evaluates the pozzolanic activity of the glass powder in three different particle sizes (150 µm, 75 µm, and 45 µm, upper limits) and compares the results with those of other added pozzolans and technical standards found in the literature. Pozzolanicity was determined by four methods: Pozzolanic Activity Index (PAI) with lime, Performance Index (PI) with Portland cement, electric conductivity, and modified Chapelle. The results of the Chapelle and electrical conductivity trials indicated the pozzolanic activity of glass powder in all three particle sizes studied. The results of PAI with lime revealed pozzolanic activity of the 45 µm fraction while the performance index with cement showed the pozzolanicity of the 75 µm and 45 µm fractions according to ASTM C 618-05 (2005). It is concluded that the smallest glass fractions provided better reaction rates due to larger contact surfaces and are, therefore, considered pozzolans.

The manufacture of glass-ceramics is an alternative route for the commercial use of metallurgical slags. Such types of glass-ceramics may find commercial applications owing to their low cost, good mechanical properties and superior visual aspect. Besides, due to the elimination of that industrial residue from the environment and also due to the possibility of replacement of natural stones such as marbles and granites, the use of slags is an activity with strong ecological appeal. While the use of blast-furnace slags for the production of glass-ceramics is well known, the utilization of steel making slags constitutes a challenge, because these materials possess low concentration of SiO2. In this work a novel composition for producing glasses and glass-ceramics from a steelmaking slag is presented. The crystal nucleation kinetics, the characterization of the resulting microstructures for two different thermal treatments and mechanical properties of the glass-ceramics are discussed. A glass-ceramic having a marble aspect, fine volumetric crystallization, high degree of crystallization and improved mechanical strength was obtained.