May 12,1923 
Effect of Decomposition on Concrete Tile 
493 ' 
From Tables XVI and XVII it would appear that the average cold 
absorption of the air tile was approximately 1.465 pounds, or 17.1 per 
cent, and that Mr. Roe’s condemnation of the tile was well founded. 
In June, 1921, an inspection of the tile was arranged for, to take place, 
on August I, Doctor Alway acting as intermediary. There were present 
the local manager of a cement association, the director of the publicity 
department of the same cement association, the engineer for a Minnesota 
concrete pipe and tile association. Dr. F. J. Alway, of the soils department 
of the agricultural engineering branch of the Minnesota Experiment 
Station, and the writer. 
Altogether, five pits were opened, the location of the first three being 
chosen by the representative of the cement association and the location 
of the last two being chosen by the writer. The first three pits were all 
opened on lateral 2 at 265, 450, and 600 feet from the main. This lateral, 
as previously described, is underlain by marl, at a depth of about i 
foot below the grade of the tile. Two tiles were taken from each pit and 
were numbered in duplicate lA, iB, and iC. At the writer’s suggestion 
branch a of lateral i was opened 20 feet from its outlet and again at 735 
feet from its outlet. The first of these two pits was underlain by marl. 
The second was in uncultivated peat and had no marl below it. Two 
samples were taken from each pit and numbered in duplicate 2A and 2B. 
The samples were set up in order on the running board of one of the cars 
and photographed by members of the party. One set was then chosen 
by the publicity director of the cement association and the other taken 
by the writer. The upper and lower sides of the samples taken by 
Elliott are shown in Plates 7, A and B. It will be noted that the tile 
which remained above the water table for long periods of time are very 
little attacked, while the tile which kept moist without much flow even 
though close to the marl is more disintegrated than those which carried a 
heavy flow of high ground water. Of the two from branch a, the tile 
taken from above the sand is more disintegrated than the one from above 
the marl. Samples of water were taken from the pits by the publicity 
man. On digging holes to the grade of the tile for the collection of 
water no water appeared. The holes were then deepened still more. At 
hole I B, the shovel handle was thrust down through the marl to the 
sand underneath. The water then rose in the hole. At pit 2 B, the hole 
was deepened almost to the underlying sand, permitting the water to 
collect. What was done with these samples is not known to the writer, 
but they can not be taken as representative of the water in the peat. 
They would be representative of the ground water in the sand subsoil, 
probably contaminated by the marl and peat.^ 
The samples of the tile taken by Elliott were tested on October 25 in 
the drainage laboratory of the experiment station. Crumbs were broken 
by hand from iB, 2A, and 2B. All showed a strong alkaline reaction. 
The results of the physical tests are given in Table XVIII. 
* Since the above was written the 1922 report of the American Society for Testing Materials has come 
to hand. It is believed that the samples tested by Dr. Witt and referred to in paragraph 3, p. 262 of 
that report, are the samples just mentioned. 
