Effect of Chlorides on Conductivity and Dielectric Constant in Hardened Cement Mortar: NDT for Durability Evaluation

Table 1

Influencing parameters for EM properties.

Type	Parameters	Characteristics of EM properties
Interior condition	Water amount	(i) Strongly affect dielectric constant and conductivity; (ii) Increase with larger amount of water
	Porosity	(i) Decrease with larger porosity
	Chloride ion	(i) Greatly increase with larger amount of chloride in water
Exterior condition	Temperature	(i) Increase with higher temperature (<10–12 GHz)
	Humidity	(i) Increase with higher humidity
Measurement condition	Frequency	(i) Dielectric constant: decrease with higher frequency; (ii) Conductivity: increase with higher frequency
	Measuring surface	(i) Increase with larger contact surface