There are a great number of soil tests available to help determine what engineering is needed before construction can begin at a site. The tests are a critical part of construction material testing (CMT) because they reveal how well the soil, and therefore a structure's foundation, will perform under various stresses. Here, we'll explain several kinds of commonly used soil tests and the soil testers that can be used to complete them.
Soil Classification Tests
Soil classification tests are exactly what they sound like: tests to help determine which type of soil is present at a construction site. For example, is the soil silty or does it have a lot of clay in its composition? Knowing what kind of soil you're dealing with will help inform the kinds of tests you perform next. It also helps predict how the soil will perform under various stresses and conditions so you can create the strongest possible foundation for your structure. Soil testers for classification testing include:
- Calcium Carbonate (CaCo3) Content Testers — frequently used to determine the quantity of calcium carbonate in marine soil specimens.
- Sand Gauges — used to define roundness and particle size, ranging from very coarse sand to fine silt.
- Soil Penetrometers (Soil Compaction Testers) — used to measure subsurface soil compaction.
Soil Density Tests
Soil density tests go a bit deeper than classification — literally. A density test is used to determine both how dense the soil at a site is and how dense it could be if compacted. Knowing soil density is critical for understanding how much the soil should be compacted prior to construction and how the soil could affect the way a structure settles over time. Soil testers for density testing include:
- Soil Compactors — used to perform compaction tests to determine wet and dry soil densities.
- Nuclear Gauges — use clouds of particles to determine inner density and structure of soil at a site.
- Sand Cone Density Testers — field testers used to determine density of particles up to 2 inches in diameter.
- Soil Density Volumeters — takes rapid measurements of cohesive soil densities.
- Voluvessels — used to test in-place soil density in compacted earth fills.
- Soil Resistance Meters — measure average soil resistivity, or its resistance to the flow of electricity.
Soil Moisture Content Tests
Soil moisture, or water content, tests are used to calculate the dry density of soil. Moisture testing equipment also determines if the soil's water content is within the required range for compaction. Common soil testers used for moisture content testing include:
- Soil Moisture Meters — use electrical currents to determine the level of moisture in soil.
- Calcium Carbide Moisture Testers (Speedy Moisture Testers) — used for rapid, accurate and reliable moisture tests on aggregates, coal, sand, ores, soils and other materials.
Soil Strength Tests
Soil strength tests are used to ensure that the soil at a construction site can handle the anticipated load. They are especially important for the safest possible construction of embankments and foundations, although they are used for a variety of other applications as well. Soil testers commonly used to perform strength tests include:
- California Bearing Ratio (CBR) Soil Testers — specifically designed to meet CBR ASTM test standards to produce laboratory, compacted or in-place soil strength test results.
- Triaxial Cells — designed to test shearing and other mechanical properties of deformable solids, like soil, clay and sand.
Permeameter tests determine the hydraulic conductivity of soil. In other words, they show how well water will flow through the soil and ensure that the site will have proper drainage. Certain permeameters are used to determine the permeability of soil samples in a lab while others can be used to perform tests on undisturbed soil on-site.
Soil Shrinkage Limit And Plastic Limit Tests
Also known as Atterberg Limits, these tests ensure that the soil beneath a structure's foundation will not change in volume or lose too much shear strength as its moisture content naturally fluctuates. The shrinkage limit is defined as the water content soil reaches where further moisture loss will not result in a greater reduction of volume. Plastic limit is determined by rolling soil samples out into "threads," with the limit being the moisture content at which the thread breaks apart at a ⅛ inch diameter.
Find All The Soil Testers You Need At Certified MTP
No matter the test, Certified Material Testing Products has the construction material testing equipment you need to get the job done safely and effectively. Browse all of our soil testing equipment and contact us with any questions.