. FORMS FOE SPECIFICATIONS, ETC., FOE EOAD MATEBIALS. 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 oe 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 J-inch screen 



Passing |-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 1 100 



Per cent. 

 Total passing i-inch 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. 



INTEODUCTION 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. 



