What is ASTM D1557?
ASTM D1557-00, Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort (56,000 ft-lbf/ft3(2,700 kN-m/m3)), ASTM International, West Conshohocken, PA, 2000, www.astm.org.
What is meant by optimum moisture content?
The water content at which a soil can be compacted to the maximum dry unit weight by a given compactive effort. Also called optimum water content.
How do you calculate optimum moisture content?
The basic premise of this simple method to calculate OMC, optimum moisture content, is based on: One (1) cubic meter (m3) of soil/sand weighs about 1,800 kg. 200 grams of soil/sand is 1/9000th of one cubic meter of the soil/sand. ALL IS DONE BY WEIGHT and not by a percent of moisture.
Which soil has highest optimum moisture content?
Note: the optimum moisture content is usually 2-3 percent less than the plastic limit of the soil….10.2 Compaction characteristics.
| Soil | Optimum moisture content for compaction (range in %) |
|---|---|
| Inorganic clay | 24 – 12 |
| Organic silt | 33 – 21 |
| Inorganic clay, highly plastic | 36 – 19 |
| Organic clay | 45 – 21 |
Why is optimum moisture content important?
The optimum moisture content provides the maximum dry unit weight that can be obtained. The increase in the dry unit weight means improving the soil properties; increased strength, decrease in permeability and compressiblity. So it is better to use the optimum moisture content.
Why is optimum moisture content of soil important?
If the moisture content of a soil is optimum for plant growth, plants can readily absorb soil water. Much of water remains in the soil as a thin film. Soil water dissolves salts and makes up the soil solution, which is important as medium for supply of nutrients to growing plants.
Is optimum moisture content?
The Optimum moisture content (OMC) or Optimum Water Content (OWC) is the moisture content at which the soil attains maximum dry density. This OMC value is with respect to the specific amount of compaction energy applied to the soil.
What is maximum moisture content?
The maximum moisture content technique for obtaining specific gravity on the basis of green volume is extremely simple and requires only determinations of the weight of the completely water saturated sample and of the weight of the ovendry sample, both of which may be made with almost equal precision.
What is a good CBR?
A clayey soil generally has a low CBR value (less than 8). Sands are more granular and drain better and will generally have CBR values between 15 and 35. Gravel will have the best CBR values, generally 25 and up. That is why it is suggested to save the best material to cap the subgrade.
What does CBR mean?
Constant Bit Rate. CBR. Case-Based Reasoning. CBR. Community-Based Rehabilitation (disability)
What is the use of optimum moisture content?
The optimum moisture content provides the maximum dry unit weight that can be obtained. The increase in the dry unit weight means improving the soil properties; increased strength, decrease in permeability and compressiblity.
Why is the optimum moisture content important?
