22 
Visual 
Inspection. 
General. 
Methods of 
Testing. 
BULLETIN 704, U. S. DEPARTMENT OF AGRICULTURE. 
If the edges of the brick are rounded, the radius shall not exceed 3 of 
an inch. 
Only bricks with lugs or projections on one side, raised not less than 3 
of an inch, nor more than 3 of an inch, shall be used. 
The ends of the brick shall have either a semicircular groove with a 
radius of not less than % of an inch nor more than of an inch, or a 
bulge of at least +; of an inch. 
The name or trade-mark of the manufacturer, if shown on the brick, 
shall be recessed and not raised. 
The brick shall be subjected to inspection subsequent to delivery at 
the place of use, prior to and during laying, in order to cull out and 
reject upon variations from the general and dimensions clauses and 
upon the following grounds: 
All brick which are broken through, or chipped in such manner that 
neither wearing surface remains substantially intact, or in such manner 
that the lower or bearing surface is reduced in area by more than one- 
eighth. 
All brick which are cracked to a depth greater than % inch on any 
surface, or which are cracked on the wearing surface. 
All brick which are so offsize or so misshaped, bent, twisted, or kiln 
marked that they will not form.a proper surface or align properly with 
other brick. 
All brick which are obviously too soft and too poorly vitrified to en- 
dure street wear. 
SAND FOR CUSHION. 
The sand shall pass a 3-inch laboratory screen and shall be well 
graded from coarse to fine. The material removed by the elutriation 
test, consisting chiefly of clay and loam, shall not exceed 5 per cent by 
weight. 
SAND FOR GROUTING. 
The sand shall consist of clean, hard, durable, uncoated stone particles, 
preferably siliceous, and free from lumps of clay and all organic matter. 
It shall be well graded from coarse to fine and, when tested by means 
of laboratory sieves, shal] meet the following requirements: 
Per cent. 
Passing 10-mesh. sievetiiit s)4 2523 tes Pee ee 100 
Passine 20-mesh sieve, not lessithan= = =. 2 eee 80 
Passing 4100: mesh Sieve, not more than _-_ = eee 10 
Not more than 5 per cent by weight shall be removed by the elutriation 
test. 
When the sand is mixed with Portland cement in the proportion of 1 
part of cement to 3 parts of sand by weight, according to standard 
methods of making 1:3 mortar briquets, the resulting mortar at the 
age of 7 and 28 days shall have a tensile strength of at least 75 per cent 
of that developed in the same time by mortar of the same proportions 
and consistency, made of the same cement and Ottawa sand. 
Preliminary acceptance samples shall be subjected to both 7 and 28 
day tests, and acceptance based thereupon. Samples tested during the. 
progress of the work wil! be accepted on the basis of the 7-day test. 
Tests of the physical properties of the brick and sand shall be made 
in accordance with the following methods: 
1. Rattler Test, A. S. T. M. Standard, C7-15. 
2. Grading of Sand, U. S. Department of Agriculture Bulletin 555, p. 33. 
8. Elutriation Test for Sand, U. S. Department of Agriculture Bulletin 
555, p. 32. 
4. Mortar Tensile Strength Test for Sand, A. S, T. M. Standard, C9-17. 
