Electrical resistivity and piezoresistivity of cement mortar containing ground granulated blast furnace slag
Construction and Building Materials
School of Engineering
Australian Government Research Training Program (RTP) Scholarship. University of Western Australia
© 2020 Elsevier Ltd Ground granulated blast furnace slag (GGBFS) is a popular used supplementary cementitious material which can increase the resistivity of cement-based composites, contribute to the cement hydration, and dense the composite structure. The piezoresistivity of cement mortar containing GGBFS was studied in this paper. Three GGBFS/cement ratio, 1.2, 1.5, and 1.8, were designed to study the effect of GGBFS content on the piezoresistivity behaviour of cement mortar. Samples were measured before and after drying treatment, and three water/binder ratios were designed to study the influence of water content on the electrical properties. Furthermore, mechanical properties and microscopy analysis were conducted. Results showed that compared to pure cement mortar, samples containing GGBFS showed an improvement in piezoresistivity behaviour. Sample with GGBFS/cement ratio at 1.2 performed the largest fractional change in resistivity of 5.57, 9.23 and 16.73 with water/binder ratio at 0.3, 0.4 and 0.5, respectively, as the concentration of pore solution was higher for samples with GGBFS/cement ratio at 1.2 compared to pure cement mortar. However, with the increasing GGBFS/cement ratio, the piezoresistivity performance was adversely affected due to the reduced pore solution concentration and conductivity caused by the increasing assumption of free calcium hydroxide. Through the investigation, piezoresistivity performance of the cement-based composite was found to be related to the mobile ions transportation with the pore solution.