May 12, 1923 
Effect of Decomposition on Concrete Tile 
499 
exceptions leading to the improvement of one quality only, and that is 
density. 
But density alone is not sufficient. In the progress of the field work, 
the greatest possible range of soils was investigated. It is significant 
that in no place where concrete tile were in peat for two or more years 
were the tile free from some percentage of disintegration. We can not 
assume that all of these tile, covering some 30 odd observations in two 
States, were below the average in quality. 
IMPROVl^MBNT NECESSARY 
It would seem that the first requisite for making the concrete permanent 
in a soil high in organic acids is the elimination of the free alkali. It is 
generally understood that an excess of lime is added to the materials of 
which cement is made in order to give it setting qualities and plasticity. 
If these qualities are necessary for a general purpose cement, it is possible 
that a special cement might be made for use in drain tile in peat soils 
which would not have the objectionable features of the standard product. 
The second suggested improvement would probably be covered by the 
first, but if the first were not put into effect it would seem that a very 
distinct improvement could be effected by finer grinding. This would 
permit of more complete hydration at the time of setting. The “ setting 
of the old tile when it was reground would seem to indicate that perhaps 
the original particles of cement were too large for the process of hydration 
to be complete even after five years. 
The third suggested improvement in the manufacture of concrete tile 
for use in peat soils is the addition of some substance which would either 
render the constituents of the cement chemically inert or would so coat 
the particles of the tile that the entrance of water would be prevented. 
If this could be done the tile would last as long as the coating remained 
intact. If such a material were used it must of necessity be of such a 
<diaracter that it itself would not decay. 
The fourth method of improvement is the one that is at present being 
used. It involves greater care in the mechanics of manufacture of the 
tile, and includes washing, grading, and elimination of soft materials 
from the aggregate, better mixing and blending and better packing and 
curing. The result is a stronger, denser tile that is greatly superior to 
the tile made by a more careless process. Its life in any soil, but par¬ 
ticularly in soils which carried inimical solutions, would be very greatly 
lengthened. It is possible that this method combined with the addition 
of a preservative substance will produce the desired results. Very great 
improvement has already been made along that line, and the utmost 
thought and care should be expended in an effort to produce a concrete 
that is unquestionably permanent. 
LITERATURE CITED 
(1) Alway, F. J. 
1922. DISINTEGRATION OP CEMENT TILE IN PEAT. In Jouf. Amer. Peat Soc., 
V. 15, no. 3, p. 15-25. References, p. 25. 
(2) Bates, P. H., Phillips, A. J., and Wig, R. J. 
1913. ACTION OP THE salts IN ALKALI WATER AND SEA WATER ON CEMENTS. 
U. S. Bur. Standards, Tech. Paper 12, [1912], 157 p., 60 fig. Bibli¬ 
ography, p. 103-105. 
(3) Bersch, Wilhelm. 
1909. handbuch der moorkultur. xii, 288 p., 41 fig., 8 pi. Leipzig. 
