DURABILITY 



It is assumed frequently by those who are unfamiliar with its 

 use that cement pipe is of doubtful permanence. Advocates of clay 

 tile have disparaged cement pipe many times and have magnified 

 the significance of such failures as have occurred. In most cases 

 these failures have been traceable easily to preventable causes. 



On the contrary, cement pipe improves with age. Sewer pipe 

 that has been in use for over thirty years has been examined and 

 single joints removed to show that it is in perfect condition. The 

 Cloaca Maxima, one of the sewers of Rome, built about 700 B. C, is 

 still in use. It is an accepted fact that concrete is not injured by 

 ordinary sewage. There are many hundreds of irrigation pipe lines 

 which have been in the ground from ten to thirty years, and which 

 are stronger now than when they were laid. 



In some parts of the United States concrete placed in strong 

 alkali soils has been injured or destroyed. The exact action ana 

 conditions of the injury have been the source of much inquiry and 

 discussion. Cooperative investigations of the effect of alkali on 

 tile are being made by the U. S. Bureau of Standards with several 

 other organizations. Eight carloads of tile were shipped to eight 

 of the best known concentrated alkali districts, one of them being 

 Yuma, Arizona. The progress report* at the end of two years 

 states that tile made of cement mixtures, not leaner than one part 

 cement to three parts aggregate, made by the wet process, which 

 requires that the molds be held in place for several hours after 

 molding, are apparently unaffected structurally when exposed for 

 two years in operative drains in concentrated alkali soils similar to 

 those included in this investigation. There was no evidence of alkali 

 in the walls of any of these tile. The great majority of the tile 

 manufactured by the dry process, which is now the most commonly 

 used commercial method of manufacturing cement tile, were also 

 unaffected, but there were some exceptions, as indicated by strength 

 tests and by the appearance of alkali salts in their fractured surfaces. 

 The exceptions, however, occurred in other states than Arizona. 

 The tile placed at Yuma, in Section 4, Township 16 South, Range 23 

 East, S. B. M., in concentrated alkali soil were not injured. 



The third progress? report shows considerable effect from alkali, 

 particularly in Colorado. Yuma stands at the foot of the list, show 



•Reclamation Record, Vol. 7, No. 8, August. 1916, p. 369. 



tBuieau of Standards. Technolosic Paper No. 9n, November. 1917. 



