188 



ANNALS NEW YORK ACADEMY OF SCIENCES 



TABLE 2 

 Effect of Cold Storage on Strength 



From these results, it is safe to conclude that, aside from the effects of 

 frost, low temperatures are adverse to the development of the hardening 

 process in cement, and that in general this effect is more pronounced in 

 mortars than in neat cement. 



The adsorption of calcium hydroxide by the complex hydrogel may 

 proceed at a lower rate at lower temperatures; or if this is not so, the 

 primary hydration, of which this hydrogel is the product, may proceed 

 more slowly, and thus less of the hydrogel be produced, either of which 

 processes will detract from the hydraulic activities of the mass. It would 

 seem from the experiments that the latter is the more satisfactory expla- 

 nation, since the test specimens which were chilled at first and allowed 

 to return to normal temperature show a tendency to return to normal 

 strength at the longer periods, while the general tendency in the series 

 kept constantly in cold water is to fall further off from the normal, indi- 

 cating only a limited available amount of hvclrosrel to undergo the coa^Ti- 



O / */ C_? o C" 1 



latin g process. 



