Fundamental experiments on the leakage of gas through cracked concrete walls

The air-tightness of concrete walls is important for nuclear-related facilities. A concrete wall has very high probability of developing cracks due to shrinkage, seismic forces or other factors. It is therefore essential to be able to predict the amount of gas which will leak through a cracked concrete wall. This paper discusses the degree of gas leakage through cracks in a concrete wall. Basic experiments were carried out on gas leakage through a cracked concrete wall. The experiment was conducted using oxygen as the gaseous body, and was based on parameters consisting of the width of the crack, the thickness of the wall and the pressure differential across the wall. In the experiment, a single tensile crack was produced in an experimental wall. The leakage rate Q was formulated as a function of W (cm) (width of the crack), Δp (pressure differential), T (thickness of the wall), μ (viscosity of oxygen gas), and D (maximum particle diameter of aggregate). (author)