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LABORATORY MEASUREMENTS OF ELECTRO-OSMOTIC PULSING TECHNOLOGY IN REDUCING RADON SOIL GAS DIFFUSION
THROUGH A CONCRETE SLAB

Y. S. Nam and K. J. Renken*
University of Wisconsin-Milwaukee, Mechanical Engineering Department Radon Reduction
Technology Laboratory, 3200 N. Cramer Street, Milwaukee, WI 53211, USA

This paper presents the experimental results of utilizing Electro-Osmotic Pulsing Technology to
reduce the diffusion of radon soil gas through a concrete slab. A laboratory system with state-of-the-art
instrumentation has been used to measure the diffusion coefficient of radon soil gas through 30.5
cm diameter, 10.2 cm thick standard composition concrete samples (w/c = 0.5 and cement:sand:gravel
= 1:2:4). Within these concrete samples, a triple titanium anode configuration is embedded while an
external copper rod is used as the cathode. To complete the circuit, these electrodes are connected to a
unique variable pulsating power supply. This unique control processor generates a variable waveform
sequence of positive, negative and neutral applied voltages with a variable pulse duration and current
amplitude. In the test apparatus, the Source Chamber is filled with Antigo Silt Loam Soil, typical of
Wisconsin soils and a passive radon gas source. The concrete sample is placed between this Source
Chamber and a Collection Chamber so that the frontal facial area of the concrete sample is adjacent to
the soil and radon gas flux. The rear facial area of the concrete slab is exposed to quiescent air.
The experimental results show as much as a 93% reduction in the radon soil gas diffusion coefficient
through the concrete slab when the Electro-Osmotic Pulsing System (EOPS) is in operation. The
effects of system operation, voltage waveform sequence, pulse duration as well as soil and concrete
relative humidity levels are documented. Details of the innovative experimental system and
procedures are described. The results of this study have indicated that Electro-Osmotic Pulsing
Technology should be considered as an effective and alternative method of reducing radon soil gas
diffusion in buildings.
Keywords: Radon; Diffusion; Concrete; Electro-osmotic pulsing technology