OIL-MIXED PORTLAND CEMENT CONCRETE. 15 



action of alkalies on concrete, suggests that another field for the use 

 of oil-cement concrete may be found in the construction of linings 

 for irrigating canals and ditches. Many of these canals are in locali- 

 ties where the soil is strongly impregnated with alkali salts and 

 where the water carried contains alkali in solution. The destructive 

 action of alkali is undoubtedly due to the crystallization of the salts 

 within the mass of the concrete, or the formation by chemical action 

 of compounds of greater volume than the original salts, or to a com- 

 bination of both of these actions. 



As the admixture of oil will retard the absorption of water into the 

 concrete, it should materially lengthen the life of the lining. In the 

 mixing of concrete for this purpose it is, of course, necessary to avoid 

 the use of either water or sand containing alkali. 1 



CONCRETE BASE FOR ROADWAYS. 



The use of this material should also prove of value for damp- 

 proofing the concrete base of roads against the action of ground 

 water, which if allowed to pass through will tend to disintegrate the 

 road surface. Such action as this is particularly noticeable with 

 road surfaces such as asphalt, bituminous concrete, etc. Assuming 

 the usual proportions for the concrete base, etc., 10 per cent of oil 

 should prove sufficient for this purpose. 



ENGINEERING CONSTRUCTIONS. 



There are many important engineering constructions in which oil- 

 mixed mortar or concrete may be advantageously employed. Among 

 them may be mentioned aqueducts, buildings, burial vaults, boats, 

 foundations, gutters, mausoleums, roofs, sewers, troughs, tanks, and 

 wells. In some constructions a coat of oil-mixed mortar is effective, 

 while in others oil-mixed concrete may be used throughout. 



It is confidently believed that, if carefully prepared oil-mixed con- 

 crete is used in structures of any kind requiring damp-proofing — 

 and in such structures careful work is a very important factor in the 

 result — there will be no difficulty experienced from leakage and the 

 structures will have been damp-proofed at very little extra expense. 



1 More detailed information relative to the use of oil-cement concrete for this purpose may be secured 

 by reference to Bulletin No. 126 of the Department of Agriculture. 



