May 12, 1923 
Effect of Decomposition on Concrete THe 
481 
Tabi^b VII 
.—Solubility of cement set 4 days and 8 months in acetic acid of 21 per cent 
strength 
Item. 
4-day set. 
8 -month 
set. 
Weie-ht of samnle. form A. . 
2 
• 559 
72. 02 
2 
r 0.4290 
1 0.4665 
/ 78.55 
\ 76. 68 
Weight of residue (gm.) -j 
Percentage of solubility j 
'(a) . \ 
i(b).; 
r(a).-I 
1(b)./ 
The two tests show an average increase in solubility of 5.50 per cent. 
If this is to be explained on the basis of calcium hydroxid becoming 
carbonated during the eight months it would indicate a proportion of 
unneutralized lime in the freshly set cement equal to 25.8 per cent, 
ANAI.YSIS OF CEMENT 
A cement company very kindly furnished the following analysis of 
their cement and a report of physical tests. 
Chemical analysis of cement, average of daily analyses, March, ig20 
Silica (SiOg). 
Oxid of Iron (FeaOg). 
Alumina (AI2O3).. 
Time (CaO). 
Magnesia (MgO). 
Sulphuric Acid (SO3). 
Toss on Ignition. 
Per cent. 
. 22. 04 
• 3-30 
62. 64 
3- 73 
I- 23 
•50 
Physical tests of the same cement, average for February, ig20 
Fineness: 
Passing 200-mesh sieve. . 81 per cent. 
Setting time: 
Initial set.. 2 hrs. 45 min. 
Final set. 5 hrs. 5 min. 
Tensile strength: 
I part cement to 3 parts standard Ottawa sand— 
3 days (i day in moist air and 2 days in water). 239 lbs. 
7 days (i day in moist air and 6 days in water). 322 lbs. 
28 days (i day in moist air and 27 days in water). 420 lbs. 
resuets of preeiminary studies 
Up to this point the work done may be considered as preliminary 
studies, though that was not the intention when some of the tests were 
begun. The principal points brought out may be enumerated as follows: 
(i) The alkalinity of the marginal and bog waters in February. 
{2) The powerful alkalinity of the tile even after 5 years in the drain. 
{3) The similarity of the old and new tile except in the matter of density. 
(4) The solubility of the thoroughly matured tile in weak organic acid. 
{5) The absorption of CO2 during long a period of curing. 
