3XPERIMENT STATION BULLETINS. 349 



IHJKAIULITY OF CONCRETE DRAIN TILE. 



Special Bulletin No. 75. 



BY 0. B. WINTER AND H. H. MUSSELMAN. 



The extensive use of concrete in manufactnring drain tile is a some- 

 what modern development, yet there are in existence today concrete 

 tile drains which were laid twenty-five or more years ago and which, so 

 far as the concrete tile itself is concerned, have given eminent satis- 

 faction. Within recent years the manufacture of concrete tile has de- 

 veloped into an industry of considerable magnitude. In fact the strides 

 made during the past few years have been very rapid. But the tile 

 produced by some manufacturers, varies greatly in quality, and the 

 manufacturers as well as the users are ignorant as to the causes of both 

 success and failure in making tile of good quality. This situation has 

 led to a number of investigations, carefully conducted by research work- 

 ers, in the effort to distinguish between good and poor tile and to dis- 

 cover the causes of success as well as of failure in the production of tilo 

 of good quality. 



As numerous requests for information in regard to these points have 

 come to the College Experiment Station, an investigation was undertaken 

 to determine, if possible, the direct causes of disintegration of concrete 

 tile in Michigan soils. The conclusions of- this investigation are not 

 final but the findings, so far reached, indicate that concrete tile can be 

 depended upon when made according to certain processes which have 

 been fairly well established as governing success. 



Whenever the disintegration of tile has been noted in our experiments 

 it has been found to be due to one or more of the folloAving causes: 



(1) the use of too lean a mixture, 



(2) the use of too dry a mixture, 



(3) improper hardening of the product after it is formed, 



(4) placing the tile in the ground before the concrete has sufficiently 

 hardened to afford proper resistance to the solvent action of soil water 

 upon the cement. The first three of these causes contribute to the pro- 

 duction of a porous tile wall structure. 



Experiments conducted by the Bureau of Standards in an endeavor to 

 determine the action of alkali and sea-water on cements indicate quite 

 clearly that: 



"Portland cement mortar or concrete, if porous, can be disintegrated 

 by the mechanical forces exerted by the crystallization of almost any 

 salt in its pores if a sufficient amount of it is permitted to accumulate; 

 and the rapid formation of crystals is brought about by drying; and, 

 as larger crystals are formed by slow crystalization, there would be 

 obtained the same results on a larger scale, but in greater time, if slov/ 

 drying were had. Porous stone, brick and other structural materials are 

 disintegrated in the '^''me manner. Therefore in alkali regions where a 



