Experimental study on the porosity evaluation of pervious concrete by using ultrasonic wave testing on surfaces

•Estimating the porosity of pervious concrete during onsite construction.•Approximating the relationship between ultrasonic wave velocity and pervious concrete porosity.•Ultrasonic wave velocity is barely affected by the thickness of the pervious concrete specimen.•The shortest path in pervious concrete occurs almost entirely within the surface layer. This research conducts two experiments (Experiments I and II) to determine methods for estimating the porosity of pervious concrete (PC) using ultrasonic wave testing. In Experiment I, the ultrasonic wave propagation on the PC surface (surface method), which can be applied during onsite PC construction, was focused on estimating the porosity of PC and the testing method itself. In Experiment II, the effect of specimen thickness on the ultrasonic wave velocity of PC was investigated. Results deduced that the quantitative relationship between ultrasonic wave velocity and PC porosity can be approximated by a quadratic function. It was confirmed that the ultrasonic wave velocity (surface method) was not affected by the thickness of the PC specimen. Therefore, as a conclusion from the results, the porosity of onsite PC construction may be estimated by using the measured ultrasonic wave velocity (surface method) according to the procedure proposed in this article (see Fig. 19 in the article in detail for the porosity estimating procedure).