Application Of Radar Technology On Concrete Moisture Testing

Water content has an important influence on concrete performance such as strength development, creep, shrinkage as well as durability. It is important for evalu-ating, reasonably, concrete performance that measure water content of concrete. At pre-sent, the techniques testing moisture content are destructive which affect the perfection of detecting techniques on water content. So it is a must that develop a technique for m-easuring water content of concrete, which is simple, reliable and non-destructiveThis paper presents researches on the technique for testing water content and mois-ture field in concrete by GPR. Through the experiments, a discussion has been carried out on the variation of velocity of radar waves and the relative dielectric constants in the concrete with different water content. Comparing the results of air drying and drying ex-periment, an equation is given to reflect the relation between the water content in the co-ncrete and the radar speed of radar waves in the concrete, aslo the relative dielectric co-nstants of concrete. Some suggestions are proposed for the actual concrete water content test by using Ground Penetrating Radar (GPR).The paper proposes a technique to measure moisture field in concrete by using GP R technique into the practical use of detecting the distribution of the humidity field insi-de the concrete, proposing some method in detecting concrete with the dielectric proper-ty layered. And it also takes advantage of the relative method of radar wave velocity la-yered, then analyze the radar wave velocity difference in each dielectric layer and final-ly we obtain the information of the one-dimensional distribution characteristic inside the concrete. By doing the experiments of detecting t the humidity field inside the concrete, combined with the equation about the relationship between the moisture content of con-crete and the spread of radar velocity, we can draw a conclusion that the water content i-nside the concrete is unevenly distributed along with the height direction, and there exi-sts obvious moisture grads. After a more in-depth study we also found that the moisture content is growing as the depth increases, but the growth trend decreases gradually.