Stefano Rizzo

Biomass ash as supplementary cementitious material (SCM)

This paper describes the research done in order to valorise the biomass ash and evaluate its use as supplementary cementitious material (SCM) in the cement industry. The biomass ash samples used in this study were collected from three different power plants. The characterisation of the ashes as SCMs was performed after two different valorisation processes: (i) a vitrification process in order to obtain a new material with high hydraulicity and (ii) an easy de-alkalisation process in order to reduce the alkali content. The results of this work show that biomass ash derived from the combustion of woodchips and straw, properly treated, is characterised by pozzolanic activity and latent hydraulicity that could be exploited for the manufacture of low embodied energy concrete. The ultimate strength of mortars prepared using vitrified biomass ash becomes higher than that of the parent Portland cement after 28 days.

Glasses and glass-ceramics as brazing materials for high-temperature applications

Abstract: Glass-ceramics can be versatile joining materials with tailorable thermal and mechanical properties; they are not affected by oxidation and can be used as pressureless joining materials above their glass softening point. The glassy phase can be minimized by a suitable thermal treatment in order to improve the glass-ceramic creep behaviour. The use of glasses and glass-ceramics as sealants in solid oxide fuel cells and as joining materials for SiC-based materials will be discussed.