In situ detection method of water content in newly poured concrete

Abstract

Under environmental influence, newly poured concrete experiences excessive evaporation of surface water, which degrades concrete performance. Therefore, the water change process inside the concrete at construction sites needs to be monitored accurately. However, existing technologies cannot fully meet this requirement. In this study, the theoretical relationship between water and dielectric constant changes inside concrete was analyzed on the basis of the dielectric constant characteristics of various components inside concrete. On the basis of the principle of standing wave ratio, a real-time and in situ electrical measurement technology for water content was proposed. The results show quadratic polynomial correlation between the measured voltage of the sensor and the water content of the concrete, and the experimental verification results show a correlation coefficient greater than 0.95 between the measured values and the theoretical relationship. The results of the application of the method in a water conservancy project site show that it has good value for in situ applications and can accurately and automatically monitor the distribution of the water content of concrete in real time.

Keywords

• water content
• dielectric constant
• in situ monitoring
• newly poured concrete