Do you have a stake in road construction and you want to ensure a stable and durable road from the construction company? Continue reading.

Road construction project requires site investigation to be carried out to understand the soil profile which affect road or pavement stability and durability. The soil tests include laboratory tests and in-situ tests.

In addition to the test on index properties of soil. Refer to article on Types of Soil Tests for Building Construction. California Bearing Ratio (CBR) Test is conducted to measure the relationship between force and penetration when a cylindrical plunger is made to penetrate the soil at a standard rate. The following are test for index properties of soil:

Particle size distribution (Sieve Analysis)

Specific gravity

Liquid limit and plastic limit tests (Atterberg test)

Moisture content test

Compaction test (Proctor’s test)

Classification of soil

California Bearing Ratio (CBR) Test

California Bearing Ratio test can be conducted in laboratory with remoulded sample or undisturbed sample in the field as an arbitrary strength test which is considered to stress soils and replicate wheel loads;

 CBR test is a measure of resistance of a material to penetration of standard plunger under controlled density and moisture conditions.

In CBR Test a cylindrical plunger of 50mm diameter penetrate a pavement component material at 1.25mm/minute. The loads for 2.5mm and 5mm are recorded. This load is expressed as a percentage of standard load value at a respective deformation level to obtain CBR value.

The harder the surface, the higher the CBR value. Typically, a value of 2% equates to clay, while some sands may have a CBR value of 10%. High quality sub-base will have a value of between 80-100% (maximum).

The CBR test is carried out on soils with a maximum particle size of 20mm. Tests are normally carried out at surface level or at depths of between 500-1000mm in 20-30m intervals along the proposed construction centerline. A minimum of three tests are usually carried out at each site.

Talk to us for your upcoming project in Soil Testing

Geodata Evaluation & Drilling LTD. offers Geotechnical Soil Testing services. Let us handle the project for you. contact us at Phone: +234 8037055441