Study of the waterfront advance in hardened concrete by means of energy level increment analysis

The durability of concrete structures depends mainly on the ease with which the water and aggressive chemical agents dissolved therein penetrate it. Moreover, the electromagnetic waves emitted by Ground-penetrating radar (GPR) are very sensitive to the water content of the medium through which they propagate. For all this, the present experimental study analyzed the sensitivity of GPR to assess the location of the waterfront in concrete by means of the comparison of the energy level increments with the absorption coefficient. For this purpose samples of concrete were fabricated and after curing were introduced into water for different time intervals. The results showed that depending on the placement of the antenna regarding the location of the waterfront the agreement varied considerably. Best agreements were found when the antenna was placed in the same surface that was immersed into water and the reflected waves were analyzed.