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Plasticity index: 6 max N.P. 10 max 10 max 11 min 11 min 10 max 10 max 11 min 11 min 1: Usual types of significant constituent materials stone fragments, gravel and sand fine sand silty or clayey gravel and sand silty soils clayey soils General rating as a subgrade excellent to good fair to poor
The plasticity index is the size of the range of water contents where the soil exhibits plastic properties. The PI is the difference between the liquid and plastic limits (PI = LL-PL). Soils with a high PI tend to be clay, those with a lower PI tend to be silt, and those with a PI of 0 (non-plastic) tend to have little or no silt or clay.
The present serviceability index (PSI) is a pavement performance measure.Introduced by the American Association of State Highway and Transportation Officials (AASHTO), the PSI is one of the most widely used pavement performance indicators after pavement condition index (PCI) and international roughness index (IRI).
Special care should be taken in depressed highways, where piers and walls should be placed at least 2 feet (0.61 m) beyond the outer edge of either shoulder. Slopes in the clear zone should be at most 1:4, and should typically be 1:6. Curbs: No curb is to be placed nearer to the roadway than the outside edge of the paved shoulder. Any curb is ...
The contract will specify AASHTO Test Designation T 22, "Compressive Strength of Cylindrical Concrete Specimens," as the means of determining compressive strength. The laboratory performing T 22 will be required to be accredited in that test. AASHTO coordinates the numbering of Interstate Highways, U.S. Highways, and U.S. Bicycle Routes.
Concrete has a very low coefficient of thermal expansion, and as it matures concrete shrinks. All concrete structures will crack to some extent, due to shrinkage and tension. Concrete which is subjected to long-duration forces is prone to creep. The density of concrete varies, but is around 2,400 kilograms per cubic metre (150 lb/cu ft). [1]
The Plasticity Index of a particular soil specimen is defined as the difference between the Liquid Limit and the Plastic Limit of the specimen; it is an indicator of how much water the soil particles in the specimen can absorb, and correlates with many engineering properties like permeability, compressibility, shear strength and others ...
The original Proctor test, ASTM D698 / AASHTO T99, uses a 4-inch-diameter (100 mm) by 4.584-inch-high (116.4 mm) mold which holds 1/30 cubic feet of soil, and calls for compaction of three separate lifts of soil using 25 blows by a 5.5 lb hammer falling 12 inches, for a compactive effort of 12,375 ft-lbf/ft 3.