WASHING AND GRADING SAND FOR CONCRETE. Vv. 
The following is an abstract from a paper on “ Quality 
of Sand for Cement Mortar,” by Mr. J. C. Hain, Engineer 
of Masonry Construction, Chicago, Milwaukee, and St. 
Paul Railway, read at Indianapolis’ :— 
‘The Bridge Department of the Chicago, Milwaukee 
and St. Paul Railway requires large quantities of sand 
every year, from numerous sources, on its system of 7000 
miles. It was therefore important to choose the shortest 
length of haul, and this led to the examination of a number 
of questionable sands. In many instances the results were 
a great surprise. 
‘‘In making the tests a mixture of 1 of cement to 3 of 
sand, by weight, was used throughout. Hach result given 
represents the average of three tensile tests. The different _ 
sands tested were grouped, and each variety was tested 
with different Portland cements, and compared with a 
sample of standard St. Paulsand. One of the sands tested 
contained foreign material, resembling clay. The damp 
sand, when taken from the face of the bank, was plastic 
and readily caked in the hand lke putty. A coating of 
fine material clung to the hand after handling it. Labora- 
tory tests, extending over three years, were made. The 
results proved that the sand was superior in every way to 
the standard sand. The 7 day and 28 day tests were 
respectively 407 and 30% above the standard. The differ- 
ence became less with age, although the 3 year test was 
still 20% above the standard. The sand tested so well that 
it was thought safe to use it for ordinary concrete. The 
question of using it under water, where clay might retard 
setting, was not gone into. 
*“T'wo other sands from one pit, the first being selected as 
the best sand in the pit, and the other as being the worst, 
were both considered doubtful, but tests proved both were 
* Abstract Proceedings of Inst., &c., Vol. cLxI. 
