Effects of moisture content and temperature on microwave measurement of lightweight foamed concrete

Abstract

The effects moisture content and temperature are important in microwave measurements and building material engineering. In this article, the relationship between the effects of moisture content/temperature and microwave measurements of lightweight foamed concrete is investigated. A frequency sweep measurement from 150 kHz to 8 GHz was performed on 10-cm cube samples with varying moisture content (0-20 %) and temperature (20°C-40°C). The microwave S-parameters were measured using an R&S ZVB8 Vector Network Analyzer with an N-type open-ended coaxial sensor and were used to calculate the dielectric constant. Models were developed to describe the relationship between moisture content, temperature, and dielectric characteristics of the concrete. Validation showed that the error was below 5 % for dielectric constant and below 8 % for loss factor at 5-GHz frequency. These findings have implications for the telecommunications industry and on-site moisture content measurements, with potential applications in building material engineering.