FORMS FOE SPECIFICATION'S, ETC., FOR ROAD MATERIALS. 33 
water is added and agitated in such manner that no whirling results. After 
settling for 20 seconds the water is poured off through a 200-mesh sieve, and 
the operation of agitation, sedimentation, and decantation repeated until the 
wash water is approximately clear. Particles caught on the 200-mesh sieve 
are then washed back into the washed sample remaining in the beaker. The 
entire washed sample is dried to constant weight and accurately weighed, 
and the 
Original weight — final weight 
Per cent by elutriation= — — 
Original weight 
(11) Mechanical Analysis, Sand ok Fine Aggeegate: 
All of the dried sample remaining after the elutriation test, if such is re- 
quired, is passed successively through the desired screens and sieves, begin- 
ning with either the largest or smallest as may be convenient. Where an 
elutriation test is not required, a dried sample of the original material is used. 
The percentage by weight, of the unwashed sample retained on each screen 
is determined, and the mechanical analysis is recorded according to one or 
both of the following methods. A screen with |-inch circular openings is 
used, together with square-mesh sieves as specified in A. S. T. M. standard 
method D7-16. 
Per cent. 
Total retained on £-inch screen 
Passing i-inch screen and retained on 10-mesh sieve 
Passing 10-mesh sieve and retained on 20-mesh sieve 
Passing 20-mesh sieve and retained on 30-mesh sieve 
Passing 30-mesh sieve and retained on 40-mesh sieve 
Passing 40-mesh sieve and retained on 50-mesh sieve 
Passing 50-mesh sieve and retained on 80-mesh sieve 
Passing 80-mesh sieve and retained on 100-mesh sieve 
Passing 100-mesh sieve and retained on 200-mesh sieve 
Passing 200-mesh sieve : 
Total 100 
Per cent. 
Total passing i-mch screen 
Total passing 10-mesh sieve 
Total passing 20-mesh sieve • 
Total passing 30-mesh sieve 
Total passing 40-mesh sieve 
Total passing 50-mesh sieve 
Total passing 80-mesh sieve 
Total passing 100-mesh sieve 
Total passing 200-mesh sieve 
Passing 200-mesh sieve elutriation 
MECHANICAL ANALYSIS AND TESTS OF PHYSICAL PROPERTIES OF 
SEMI-GRAVEL, TOP-SOIL, AND SAND-CLAY AGGREGATES. 
INTRODUCTION BY THE COMMITTEE. 
The committee has been charged with consideration of that large range of 
natural soils and aggregates which lie below the usual classification of gravel, 
and which in the past 10 years have commended themselves to low-cost road 
1 If the sand is so coarse that a 100-gram sample is not sufficient, the size of the 
sample, the container, and the amount of water used may be proportionally increased. 
