Experimental study on the dielectric properties of non-aqueous reaction polyurethane grouting materials

The dielectric properties of polymer grouting materials are the key to nondestructively evaluate the grouting effect. In this study, 40 groups of non-aqueous reactive polymer specimens with different densities were prepared, and their dielectric constants were measured at frequencies from 500 MHz to 6000 MHz, and the mechanism was analyzed in conjunction with the microstructure diagram. The polymer was found to be a porous biphasic system, and the microphysical and dielectric models were constructed accordingly. The results show that the dielectric constant increases with increasing density and decreases slightly with increasing frequency; the conductivity is enhanced with increasing frequency. And the non-aqueous reactive polyurethane grouting material has a low value of dielectric constant and low dielectric loss. Finally, comparing the four dielectric models, the Maxwell-Garnett equation has the highest prediction accuracy and the lowest error. This study provides a theoretical basis for the nondestructive testing of polyurethane grouting materials, which is expected to improve the accuracy of the quality assessment of seepage control and reinforcement of embankment dams, roads and other projects, and is of great practical significance.