Om Materialprøvningens Udvikling i Norden
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does not seem to differ very much in common-bricks and sand' lime-bricks, and it is this matter, which is of importance to the problem before us. Table VI. Average Weight in g for all the 10 Bricks tested. Dried at about 100° be- fore being sa- turated with water Saturated with water After being dried in 26 days and nights Dried at about 100° af- ter being sa- turated with water and dried Sand-lime-bricks 2562 2896 2669 2574 Bricks 2263 2602 2264 2261 Similar experiments made at the Berlin Testing Laboratory have given the same result; cp. Burchcirtz: Die Prüfung und die Eigenschaften der Kalksandsteine, Berlin 1908, S. 89. The Laboratory does not, however, agree with Mr. B. in that it is principally due to a chemical process, the transformation of the calcic hydrate to carbonate of lime, that the sand-lime- bricks after being dried do not return to their original weight. In that case the greater part of this augmentation of weight would not disappear on the bricks being heated to 100° (cp. Table VI). The Laboratory is, on the contrary, of opinion that on the sand- lime-bricks retaining the water in the cavities to a much higher degree than the bricks, this difference is not due to casualties but to the different quality of the cavities of the bricks. IV. Conclusion. The evaporation from the surface of bricks, saturated with water or very wet, being not less for sand-lime-bricks than for common bricks and the capillary attraction being as a rule ap- parently considerably less, there is presumably no reason for maintaining a test the severity of which for the sand-lime-bricks is principally due to matters which cannot be seen to be of any importance in nature. The Laboratory is, certainly, inclined to think that the bricks as regards the corners (cp. above) have the advantage of the sand-lime-bricks, but this advantage will show itself sufficiently clearly by the new test.