Ionic thermoelectric effect of pure cement paste and its temperature sensing performance

Abstract

Incorporating functional fillers into the cement matrix can provide cement-based materials with electronic carriers to enhance the electronic thermoelectric effect for the utilization in the future intelligent infrastructures. However, incorporating multiple types and high amounts of functional fillers might increase the cost, degrade the mechanical properties, and hinder the wider application of the intelligent cement-based composites. In this study, the electrical conductivity and the thermoelectric effect of the pure cement paste after sealed curing, after drying, and after leaching are investigated as a potential highly efficient thermoelectric material. The mechanism of the ionic thermoelectric effect is discovered and evaluated. The temperature sensing properties of the pure cement paste under the gradient heating and the temperature cycles are measured. In addition, a cement-based temperature sensor is further developed, and its temperature sensing performance is tested. It is found that the pure cement paste exhibits an ionic thermoelectric effect due to the existence of ions in the pore solution, with the advantages of high Seebeck coefficient, high electrical conductivity, and low cost. The temperature sensor consisting of four pure cement paste elements saturated for 3 hrs followed by leaching for 72 hrs endorses a good sensing performance to temperature changes. The findings in this study show promising utilization possibilities of the thermoelectric cement-based materials in the field of constructing intelligent infrastructures.