2006 Volume 47 Issue 3 Pages 132-137
A number of defective conditions such as coarse aggregate spalling are visible on cast-in-place concrete tunnel linings covered with accumulated soot emitted by steam locomotives. It is apparent that such defects have mainly occurred at construction joints or honeycombing existed since the beginning of the concrete construction. We conducted a study into the mechanism of such defects; hence, this paper describes the results of the study and countermeasures to cope with such defects.