Enhancing piezoresistivity of cement sensor with supplementary materials and carbonation curing

Abstract

This study explores the fabrication of cement-based sensors blended with supplementary cementitious materials (SCM) using carbonation curing. The effects of SCM types (i.e. fly ash or slag) and curing conditions on degree of carbon dioxide uptake, compressive strength, electrical conductivity and piezoresistive sensing capability were systematically examined. The results indicate that the inclusion of fly ash or slag enhances the degree of carbon dioxide uptake. However, it is also found that the excessive carbonation curing negatively affects compressive strength. Electrical resistivity is increased after carbonation curing due to carbonation-induced hydrate formation disrupting carbon nanotube-based conductive networks. The piezoresistive sensing capability is influenced by binder types and curing conditions, with higher sensitivity observed in samples blended with fly ash.