May 12, 1923 
Effect of Decomposition on Concrete Tile 
473 
composed almost entirely of moss and other low order plant accumula¬ 
tions, without inwashed soil or lime. 
Vogler (i5) in his Grundlehren der Kulturtechnik,’' published in 1909, 
draws a strong distinction between low moor and high moor, repeatedly 
affirming the resistant quality of cement tile in low moor and its destruc¬ 
tion in high moor. 
Tacke (jj), in 1910, published a paper on the substances in peat 
which would probably be destructive to concrete. He mentions the dis¬ 
integration of concrete in a moor containing as high as 17 per cent of 
iron pyrite. He also discusses the probable destruction from humic 
acids of concrete in high moor and its permanence in low moor. 
Bersch { 3 ) in his “ Handbuch der Moorkultur,’’ published in 1909, makes 
the same distinction between low and high moor as does Vogler, and 
draws the same conclusions regarding the durability of the concrete 
tile in the two classes of peat. 
None of these authorities followed up his observations by any pub¬ 
lished research results, but the behavior of concrete tile in peat was con¬ 
sidered of such importance that a subcommittee of the German 
Committee on Reinforced Concrete was assigned to the task of making 
investigations. Their work was interrupted by the war. 
In this country previous to 1921, if there had been any suspicion of 
destructive effect on concrete tile due to weak soil acids, no report had 
been made of any investigations induced by such a suspicion. Wig, 
Williams and Finn (17) in 1917, while investigating the effect of alkali 
on tile, noted a disintegration that took place on one of their tile lines 
at Columbia, Mo., where tile were laid in supposedly neutral soil as a 
control against the disintegration of similar tile laid in alkaline soil. 
They say in their report: 
An exceptional condition has arisen at this project, presumably caused by some 
local action, in that the tile of series i to 16, excepting series 5 (tar coated), showed 
evidences of disintegration on the lower outer surface, indicated by the apparent 
dissolving away of cement leaving the sand grains coated with a brown stain. 
The tile at Columbia were laid in mineral soil overlaid by 12 to 15 
inches of black soil. 
Williams (19) in 1922, reports on the same tile that in all cases except 
those which had been in the ground only one and two years, and those 
which were tar coated, the tile were stained and pitted. 
Alway (j) in 1922, refers to the work of Tacke at some length. He 
questions the probabilities that the breaking down of the concrete tile 
is due to the action of organic acids or that concrete tile break down in 
peats containing a high percentage of lime. He says: 
Humic acids are not carried in the bog water of high lime peats. These acids are 
more or less soluble in pure water and in weak mineral acids, as phosphoric and boric, 
but insoluble in hydrochloric and sulphuric acids. With soluble compounds m 
calcium, magnesium, iron and aluminum, they form insoluble compounds,, so called 
humates which are insoluble in water as well as in moderately concentrated alkali 
solutions. 
Soluble sulphates, particularly those caused by the breaking down of 
iron pyrite (a common condition in acid peat bogs) seem to him to be 
the most probable cause of disintegration, but he also includes hydrogen 
sulphid and alkali waters. , 
Stewart { 12 ), collaborating with Doctor Alway, and writing in the same 
publication, makes a direct statement along the lines suggested by Doctor 
Alway’s paper. 
