Analysis of a thaumasite attack in a railway tunnel

Abstract

Concrete linings failed before the acceptance of a railway tunnel in a north mountain area of China. A series of experiments were done to analyze the cause of this case. Thaumasite, ettringite, gypsum and calcite were found in the deteriorated concrete linings. The composition of on-situ soil and water samples were also analyzed. Though the sulfate concentration soil behind the linings are not very high, the underground water bring plenty of sulfate after its upsteam flow through a gypsum stratum. It is the external sulfate that induce the deterioration in a low temperature environment which is suitable for thaumasite formation.