XI, A, 6 



Witt: The Effect of Sulphide on Cement 



275 



Renezeder" has carried on some experiments on the effect 

 of sodium sulphide solutions on briquettes. He placed a number 

 of briquettes, of both slag and Portland cement, in sodium 

 sulphide solutions of various concentrations. Other briquettes 

 of the same kind were kept in water for comparison. The 

 test pieces were broken at the end of one, three, six, and twelve 

 months, respectively. The briquettes which had been immersed 

 in the sulphide solution were all weaker than the ones which 

 had been kept in water. However, the writer states that if 

 a briquette is kept in water for the first several weeks, and 

 then placed in sulphide solution, no bad effects are noted. 



The present work was undertaken in an effort to obtain data 

 on the following points : 



The concentration of sulphide which may be present in water used in 

 making concrete, without causing any injurious effects. 



The effect of sulphide solutions of accurately known concentrations 

 on the setting time and tensile strengths of various cements. 



Any chemical reactions which take place. 



Since it was desired to make the work as comprehensive as 

 possible, five barrels of cement, each of different brand, were 

 purchased in the open market for the work. The brands chosen 

 represent a wide range in method of manufacture and in com- 

 position. The contents of each barrel were thoroughly mixed. 

 Samples of sufficient size to make the usual physical and 

 chemical tests were taken, and the remainder was placed in 

 large tin cans with tightly fitting covers and preserved until 

 used. The five brands of cement will be referred to in this 

 paper as A, B, C, D, and E. The chemical analyses are given 

 in Table I ; the physical tests, in Table II. 



Table I. — Chemical analyses of cements.' 



Loss on ignition 



Insoluble residue 



Silica (Si02) 



Alumina (AbOs) 



Ferric oxide (Fe203) 



Calcium oxide (CaO) 



Magnesia (MgO) 



Sulphuric anhydride (SOs) 



Potassium and sodium oxides (K2O, Na20) . 



A. 



B. 



C. 



Per 

 cent. 



Per 

 cent. 



Per 

 cent. 



2.50 



2.80 



1.60 



0.30 



0.60 



0.30 



2L10 



20.00 



22.50 



8.76 



8.86 



7.58 



1.42 



1.34 



1.12 



63.10 



63.00 



63.00 



1.26 



1.34 



1.74 



0.67 



0.86 



1.34 



0.93 



1.16 



0.87 



Per 



cent. 



2.40 

 0.80 



18.80 

 9.18 

 1.12 



64.10 

 1.12 

 1.34 

 1.16 



E. 



Per 

 cent. 



2.00 



0.45 



18.95 

 9.52 

 1.38 



63.80 

 1.80 

 1.24 

 0.87 



Analyses by Francisco Pena, inorganic chemist; Bureau of Science.- 



"Renezeder, H., ibid. (1907), 31, 237. 



