Types of soil evaluations for road building project demands the site investigation to be carried out to understand the soil profile. For road building functions, the possessions of soil at subgrade level are required.
The common soil evaluation for the street building includes classification of soil, particle size distribution, moisture content determination, specific gravity, liquid limit, and plastic limit evaluations. Moisture content, particle size and specific gravity tests on soils are employed for the improvement of soil properties such as degree of saturation.
The soil tests could be laboratory tests or in-situ tests. The lab tests should be carried out on each sample obtained for the determination of particle size and moisture content.
Kinds of Soil Tests for Road Construction
Following are the Various Kinds of soil evaluations for sidewalk construction:
The moisture content of soil evaluation is carried out in the laboratory. It’s expressed as a percentage of water from the soil to its dry mass. The moisture content in soil suggests the various properties of soil such as compaction, permeability, particle size etc..
The specific gravity of soil is that the proportion of the weight of soil in the air of a given volume in a typical temperature to the weight in air of an equal volume of distilled water at the same stated temperature. This test is also carried out in a lab.
This test determines the particle size distribution of dirt from the coarse sand size down to nice clay dimensions. The data from particle size distribution evaluation is utilized to ascertain the suitability of land for street construction, airfield etc.. This evaluation can also be used to predict soil water movement even though permeability tests are more commonly used.
Compaction test — Proctor evaluation
This soil compaction test also called as Proctor test is employed for the determination of the mass of dry soil per cubic meter once the soil is compacted within a selection of moisture contents, providing the maximum dry density at optimum moisture content. Thus this evaluation provides that the compaction characteristics of different soils with a change in moisture content. This is reached by the densification of soil by lowering the air voids.
The level is quantified with regard to its dry density of soil. The dry density is greatest at the optimum water content.
California Bearing Ratio (CBR) Test
California Bearing Ratio test is conducted in the laboratory. This test provides the load penetration resistance of the soil. CBR value is obtained by quantifying the relationship between force and penetration when a cylindrical plunger is made to permeate the soil at a typical pace.
The CBR evaluation is used for the test of the subgrade strength of roads and pavements. The CBR value obtained by this test is used with the empirical curves to determine the depth of pavement and its component layers. This is the most frequently used method for the design of flexible pavement.
Even though the provision of subsoil drains reduces the effect of water on the subgrade, entirely soaked CBR tests will be regarded as suitable for road-building projects. You can also check out cbr ground testing
After points should be taken care of while soil testing for street building:
- Sampling and Testing: Sampling of soil for evaluations in laboratory or in-situ is to be carefully done by experienced engineers. The need for a variety of mass/volume of soil at different points of a street project shall be followed as per the specification and regular codes.
- Test Data Logging: Logging of all the dirt sample and test data shall be done by trained staff who has the understanding of soil properties and tests results.
- Testing Frequency: The testing frequency of soil shall be according to input from Engineer. The conclusion on the testing frequency is usually accepted on the basis of results obtained from the previous evaluations.