AASHTO Soil Classification
AASHTO M 145: Classification of Soils and Soil Aggregate Mixtures for Highway Construction
AASHTO T 27-14 standard covers the determination of the particle size distribution of fine and coarse aggregates by sieving. Accurate determination of material finer than the 75-μm (No. 200) is achieved by combining this method with AASHTO T 11.
Weigh Balance of sufficient capacity, readable to 0.1 percent of the sample mass, or better.
Mechanical Sieve Shaker - Recommended when the size of the sample is 20 kg (44 lb) or greater, but may be used for smaller samples as well including fine aggregate. It may be noted that excessive sieving time (more than approximately 10 min) using a mechanical sieve shaker may result in degradation of the sample.
Oven of appropriate size capable of maintaining a uniform temperature of 110 ± 5°C (230 ± 9°F).
Sample the aggregate in accordance with AASHTO T 2. For fine aggregates, The size of the test sample of aggregate, after drying, shall be 300 g minimum.
For coarse aggregates (and for combined sample of coarse and fine aggregate mixtures), after drying, shall conform with the requirements given in table below.
|Nominal Maximum Size||Minimum Mass|
|9.5 mm (3/8 in.)||1 kg (2 lb)|
|12.5 mm (1/2 in.)||2 kg (4 lb)|
|19.0 mm (3/4 in.)||5 kg (11 lb)|
|25 mm (1 in.)||10 kg (22 lb)|
|37.5 mm (1 1/2 in.)||15 kg (33 lb)|
|50 mm (2 in.)||20 kg (44 lb)|
|63 mm (2 1/2 in.)||35 kg (77 lb)|
|75 mm (3 in.)||60 kg (130 lb)|
|90 mm (3 1/2 in.)||100 kg (220 lb)|
|100 mm (4 in.)||150 kg (330 lb)|
|125 mm (5 in.)||300 kg (660 lb)|
For aggregates with a nominal maximum size of 12.5 mm (1/2 in.) or less, the same test sample may be used for testing by AASHTO T 11 as well. The sample is first tested in accordance with AASHTO T 11 through the final drying operation and subsequently dry sieved. For aggregates with a nominal maximum size greater than 12.5 mm (1/2 in.), a single test sample may be used for both AASHTO T 11 and this method (both wash and dry sieving conducted on the same sample) or separate test samples may be used for AASHTO T 11 and this method.
If the test sample has not been subjected to testing by AASHTO T 11, dry the test sample to constant mass at a temperature of 110 ± 5°C (230 ± 9°F). Determine the mass to the nearest 0.1 percent of the mass of the test sample.
Select appropriate sieves (with suitable sieve openings) to furnish the information required by the specifications covering the material to be tested. Nest the sieves in order of decreasing size of opening from top to bottom and place the sample, or portion of the sample if it is to be sieved in more than one increment, on the top sieve. Agitate the sieves by hand or by mechanical apparatus. Continue sieving for a sufficient period and in such manner that, after completion, not more than 0.5 percent by mass of the total sample passes any sieve during 1 min of continuous hand sieving.
Determine the mass of each size increment on a scale or balance. The total mass of the material after sieving should check closely with the total original dry mass of the sample placed on the sieves. If the two amounts differ by more than 0.3 percent, based on the total original dry sample mass, the results should not be used for acceptance purposes.
Calculate percentages passing, total percentages retained, or percentages in various size fractions to the nearest 0.1 percent on the basis of the total mass of the initial dry sample. If AASHTO T 11 was performed on the same test sample, include the mass of material finer than 75-μm (No. 200) sieve by washing in the sieve analysis calculation; and use the total dry sample mass prior to washing in AASHTO T 11 as the basis for calculating all the percentages.
|Sieve Size, mm||
Cum Wt. Retained
Cum Wt. Passing