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gravel > 50% of coarse fraction retained on No.4 (4.75 mm) sieve clean gravel <5% smaller than No.200 Sieve GW well-graded gravel, fine to coarse gravel GP poorly graded gravel gravel with >12% fines GM silty gravel GC clayey gravel sand ≥ 50% of coarse fraction passes No.4 (4.75 mm) sieve clean sand SW well-graded sand, fine to coarse sand SP
The AASHTO Soil Classification System was developed by the American Association of State Highway and Transportation Officials, and is used as a guide for the classification of soils and soil-aggregate mixtures for highway construction purposes.
A poorly-graded soil is a soil that does not have a good representation of all sizes of particles from the no. 4 to no. 200 sieve. A poorly-graded gravel is classified as GP, while a poorly-graded sand is classified as SP. Poorly-graded soils are more susceptible to soil liquefaction than well-graded soils. [1]
In Europe, sizing ranges are specified as d/D, where the d shows the smallest and D shows the largest square mesh grating that the particles can pass. Application-specific preferred sizings are covered in European Standard EN 13043 for road construction, EN 13383 for larger armour stone, EN 12620 for concrete aggregate, EN 13242 for base layers of road construction, and EN 13450 for railway ...
The sand equivalent test quantifies the relative abundance of sand versus clay in soil. It is measured by standardized test methods such as ASTM D2419, AASHTO T176, and EN 933–8. [ 1 ] The test is used to qualify aggregates for applications where sand is desirable but fines and dust are not.
The California Department of Transportation has developed a similar test, California Test 216, which measures the maximum wet density, and controls the compactive effort based on the length (in fact the height) of the test sample and not on its volume. The primary advantage of this test is that maximum density test results are available sooner ...
Crushed sample is then separated from fine dust on a sieve, washed, dried and weighed. [6] The test reports loss of mass to abrasion and impact, expressed as a percentage of initial sample mass. [7] Maximum acceptable loss for the base course of the road is 45%; the more demanding surface course must be 35% or less. [1]
Gravel is a major basic raw material in construction. [24] Sand is not usually distinguished from gravel in official statistics, but crushed stone is treated as a separate category. In 2020, sand and gravel together made up 23% of all industrial mineral production in the U.S., with a total value of about $12.6 billion.