IX, A, 2 



Reibling: Natural Cement versus Brick 



171 



Table VII. — The setting properties of cements 1, 2, 3, and k aerated for 



eighteen hours. 



Mix- 

 ture 

 No. 



Per cent 

 plaster 

 added. 



Per cent 



water 

 required 

 for nor- 

 mal con- 

 sistency. 



Time of setting in 

 minutes. 



Initial. 



Final set. 







35 

 34 



50 

 50 



600 

 440 



1.0 



1 



2.0 



34 



45 



340 





2.5 



34 



35 



285 



2 





35 



34 



80 

 55 



600 

 480 



1.0 



2.0 



34 



50 



400 





2.B 



34 



45 



480 







35 

 34 



70 

 55 



500 

 140 



1.0 



3 



2.0 



35 



50 



110 





2.5 



35 



55 



90 



4- 





40 

 37 



115 

 80 



600 

 540 



1.0 



2.0 



37 



70 



525 





2.5 



37 



70 



510 



Unfortunately, there was not enough material left to test the 

 hardening properties of cements 3 and 4, but the data in Table 

 VIII show the excellent results obtained with 1, not seasoned, 

 and 2, aerated for eighteen hours. Each strength recorded is 

 the average of four tests; and it is worthy of mention that the 

 differences between the average and the maximum and minimum 

 results were remarkably small compared to the variations 

 usually obtained with Portland cements. 



Table VIII. — Hardening properties of natural cements 1 and 2, containing 



1 per cent of plaster. 



Test. 



Results. 



Require- 

 ments of 

 specifica- 

 tions.* 



Cement 



1, not 



seasoned. 



Cement 2, 

 aerated 

 18 hours. 



Tensile strength in pounds per square inch: 

 Neat mortar — 



1 day in moist air 



91 



256 

 296 

 313 

 370 



144 

 182 

 214 

 317 



94 

 233 

 295 

 306 

 336 



141 

 194 

 237 

 242 







150 



(b) 



250 

 (b) 



60 



(b) 



125 



(b) 





1 day in moist air, 27 days in water ~ __ 



1 day in moist air, 90 days in water 



1:3, Ottawa-sand mortar— 



1 day in moist air, 6 days in water 



1 day in moist air, 18 days in water - ..- 



1 day in moist air, 27 days in water ._ 



1 day in moist air, 90 days in water 





" /Ij/i. Soc. Test. Mats. (1912). 



b Not given. 



