Electrical capacitance tomography to monitor unsaturated moisture ingress in cement-based materials

This paper reports the investigation of the feasibility of electrical capacitance tomography (ECT) for monitoring unsaturated moisture flow in cement-based materials. ECT is an imaging modality in which the electrical permittivity distribution within an object is reconstructed based on measured capacitances between electrodes attached on the object's surface. In a series of experiments, mortar specimens with different water-cement mass ratios (w/c) (0.25, 0.45 & 0.60) were monitored with ECT during the moisture ingress. The results demonstrate that ECT is able to image the moisture ingress within the specimens, and further, to distinguish between different moisture flow rates in mortars with different porosities resulting from differing w/c ratios. These findings suggest that ECT could provide a tool for monitoring, visualizing and quantifying the rate of moisture ingress in cement-based materials non-destructively.