Soil Testing Equipment

for Laboratory Evaluation

Humboldt provides and extensive offering of testing equipment for evaluating and analyzing construction soils in the laboratory. Lab testing equipment for soil includes the following types of soil testing:

Proctor Testing
Soil compaction equipment for tests such as the Proctor, both standard (ASTM D698 or AASHTO T99) and modified (ASTM D1557 and AASHTO T180) variants. Proctor testing was developed in the early 1930s and has been used extensively to determine the relationship of moisture and density in compacted, cohesive soils. By developing a curve using varying degrees of moisture with a standard compaction procedure, the Standard Proctor and the Modified method can be used to determine the optimal moisture content of soils as well as determining the resulting density and percent compaction of a soil. Typical testing equipment for these tests would include test-specific molds, found here: Proctor Molds and hand or automatic compactors found here: Proctor Compactors

California Bearing Ratio
A similar test that also uses compactors and test-specific molds would be the California bearing ratio or CBR tests (ASTM D1883 and AASHTO T193). This test was developed by the California state highway department and is widely used to determine the resistance strength of sub-grade and sub-base materials. The test is a simple penetration test, which utilizes a load frame and a standard CBR mold. CBR load frames can be found here: CBR Load Frames

Atterberg Limits
Another series of laboratory soil tests are the Atterberg limits, which are a basic measure of the critical water content of fine-grained soils. These tests include shrinkage limit, plastic limit, and liquid limit, which are outlined in ASTM D4318. Testing equipment for these tests can be found here: Atterberg Limits

Hydrometer Analysis of Soil
When determining the particle-size distribution of fine-grained soils in the testing lab, the sedimentation or hydrometer method (ASTM D7928) is used. In this test a hydrometer is used to determine the particle-size distribution of material that is finer than the No. 200 (75um) sieve and larger than about 0.2um. Hydrometers, jars and jar baths can be found here: Hydrometer Analysis

Permeabilty Testing
Permeability testing of soil is also a standard test in the soils laboratory. Permeability testing (ASTM D2434 and ASTM D5084) measures the rate of discharge of water under laminar flow conditions through a cross-sectional area of a porous medium. In permeability testing, soil is subjected to water under a known pressure and the flow is measured. Testing equipment for this type of testing can be found here: Permeability Testing