Macroscopic ice lens growth: Observations on Swedish concrete dams

摘要

The arch dam at Selsforsen and the buttress dam at Storfinnforsen are two concrete dams of which both have suffered from severe surface spalling on the upstream face, far below the full water supply level. A hypothesis is that macroscopic ice lens growth, similar to frost heave in soil, could have occurred within the dam walls. After initial deterioration of the concrete dams by frost damage or cracking, the formation of macroscopic ice lenses could have been made possible. In an attempt to test the hypothesis, specimens of low strength concrete were exposed in the laboratory to climatic boundary conditions similar to those of the dams. After one week of freezing, the upper part of the concrete specimens was separated from the lower part due to cracking. The gradual propagation of the crack, which appeared about 25 mm below the top surface, was caused by macroscopic ice lens growth.