358 STATE I30ARn OF AGRICULTURE. 



out further curing.'- They were laid iu the spring of 1912 and were 

 removed from the ground in December, 1913. 



Some tile left on the surface of the ground near (he drain and some 

 of the tile in the drain were in good condition. Others in the drain 

 were slightly' disintegrated, and still others almost entirel}' destroyed. 



Other points of interest in this report were that all of the tile laid 

 in clay soil were apparently sound and that of two adjoining tile laid 

 in muck soil, occasionally one was found in good condition and the 

 other badl^' disintegrated. 



From all appearances, the materials used in the manufacture of 

 these tile were of a good grade, but the lack of uniformity of these 

 materials, the porous condition of the matrix, and the fact that occa- 

 sionally two adjoining tile were found, one of which was sound and 



Fig. 4. — End views of sound and partially disintegrated tile, showing that disintegration is usually 

 more pronounced at the top or bottom depending on whether the soil water percolates from 

 above or below. 



the other badly disintegrated, show i)Oor mixing and packing of the 

 concrete. It is also evident that these tile were not sufficiently hard- 

 ened before laid, and experiments show that this condition may be 

 favorable to rapid disintegration. 



Samples of tile from lots two and four were so badly disintegrated 

 that no statement can be made as to the cause of disintegration. 



Samples from lot three contained a small percentage of particles 

 too large to use iu the preparation of concrete tile i/o-inch thick. They 

 also contained some organic matter and clay, and probably the worst 

 feature of all was that the material was not properly mixed and packed 

 (there were some spots in the tile wall nearly an inch long where the 

 particles were not in close contact and therefore not cemented together) . 

 The matrix of fine sand and cement was very porous and not in close 

 contact with the larger particles. Such tile are weak and easily af- 

 fected bv soil water. 



