480 
Journal of Agricultural Research 
Vol. XXIV, No. 6 
ANALYSIS OF AGGRl^GAT^ 
A screen analysis of the sand and gravel aggregate used in the manu¬ 
facture of the tile gave: 
Grade: 
Coarser than 10 mesh 
10 to 20 mesh. 
20 to 40 mesh. 
40 to 60 mesh. 
60 to 80 mesh. 
80 to 100 mesh. 
100 mesh. 
Per Cent of Total. 
46. 6 
13-4 
18. 2 
12. 2 
4.8 
1. 6 
2. 4 
09 - 2 
Tomlinson® has calculated the mineralogic proportions in Waukesha 
sand by relative density and miscroscopic count, proportions of car¬ 
bonates and of quartz in different sizes of Waukesha sand, as follows: 
Group. Carbonates. 
Coarser than 10 mesh. 72. i 
10 to 20 mesh. .... 72. i 
20 to 40 mesh. 55. 7 
40 to 100 mesh. 36. 9 
Quartz. 
1-5 
7.0 
35-4 
58. I 
Proportion of Mineral groups in Waukesha sand 
Group: Percent. 
Igneous rock. o. 42 
Shale group. 
Quartz group.. 32.31 
Dolomite group. 65-37 
Feldspar.. 
Heavy minerals.%..83 
Not sorted. i. 07 
100. 00 
TESTS OF CEMENT 
Both the old and the new tile had been made with a slag Portland 
cement of average chemical composition. This cement was also treated 
with acetic acid to ascertain its solubility. It showed a trace of carbonic 
acid bubbles. 
A quantity of the cement was^ mixed into a thick paste with water, 
thoroughly worked and rolled into balls by hand, then flattened on glass, 
made into patties and allowed to set one day under a moist cloth. At 
the end of that time, the patties had set firmly and showed no signs of 
malformation, swelling, or shrinkage cracks. Boiled one hour in water, 
they showed no signs of failure. 
Some of the patties were allowed to set three days in water and at the 
end of that time appeared to be in perfect condition. They were then 
powdered, and 2 gm. dried at no C°., were treated with 21 per cent 
strength acetic acid. Other patties, made in a similar way at Minnesota, 
were allowed to set in water for three months, and then five months 
in air at a temperature averaging 75° F. These were powdered and 
treated like the others. The ffrst test showed no evolution of bubbles, 
but the second gave bubbles in considerable amount, showing that the 
cement had carbonated during the eight months set. The result of the 
two tests are tabulated in Table VII. 
* Tomlinson, C. W. unpubushbd thesis. Uuiv. of Wis., Col. of Engin., 1915. 
