Lisø PhD Dissertation Manuscript - NTNU

Fig. 2. Example illustrations of the main defect categories. See Table 1 for explanation.
Fig. 3 presents an analysis on how the main defect categories vary through four 5year
periods. There is a pronounced increase in the number of assignments over the 20year
period. However, a few time dependent trends can be seen. For instance, sulphate
attack on LECA blocks (Light Expanded Clay Aggregate concrete, see category E) was a
common defect cause only in the first ten-year period. Low frost resistance of new lightcoloured
clay bricks on the marked constitute the bulk of the increase in defect cases
within the last five-year period. The overview in Fig. 2 and Fig. 3 does not differentiate
between varying types of masonry. However, the analyses of masonry defect cases in the
Page 5 of 12