Which Soil Testers Do You Need Before Construction?

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. These 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 before 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 the inner density and structure of soil at a site.
• Sand Cone Density Testers — field testers used to determine the 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.

Keep Reading: How a Construction Testing Lab Validates Material Quality.

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.

Soil Permeameters

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.

Soil testers are essential instruments in agriculture, construction, environmental science, and landscaping. They provide valuable information about the composition, structure, and health of soil, which is crucial for various applications ranging from farming to civil engineering.

Types of Soil Tests:

1. pH Testing: One of the most common and important tests, pH testing reveals the acidity or alkalinity of soil. Soil pH affects nutrient availability to plants and microorganism activity. Most plants prefer a slightly acidic to neutral pH, and deviations can lead to poor plant growth.

2. Nutrient Analysis: This involves testing for essential nutrients like nitrogen, phosphorus, potassium, and others. Nutrient tests help in determining the fertility of the soil and are vital for effective fertilization management in agriculture.

3. Moisture Content Test: Understanding soil moisture is crucial for irrigation planning. Over-watering or under-watering can lead to poor crop yields or increased susceptibility to disease.

4. Compaction and Density Tests: Especially important in construction, these tests determine the soil’s ability to support structures. Compaction tests assess how densely the soil particles are packed, affecting their strength and stability.

5. Organic Matter Content: This test determines the amount of organic material in the soil, which can significantly affect its fertility and structure.

6. Salinity Test: High levels of salts can hinder plant growth. Salinity tests are essential in areas with saline irrigation water or in coastal regions.

Applications of Soil Testing:

1. Agriculture: Soil tests guide farmers in fertilizer application, ensuring optimal plant growth and yield.

2. Environmental Monitoring: Soil testing helps in assessing pollution levels and the health of ecosystems.

3. Construction: Tests like compaction and density are critical for determining the suitability of soil for construction projects.

4. Landscaping and Gardening: Soil testing assists in selecting suitable plants and maintaining healthy gardens.

Challenges and Limitations:

While soil testing provides valuable insights, it also comes with challenges. Soil heterogeneity means that samples may not represent the entire area. Additionally, the accuracy of results depends on the quality of the testing methods and instruments.

Conclusion:

In summary, soil testers play a pivotal role in various fields, providing critical data for making informed decisions. Whether it’s for ensuring agricultural productivity, assessing environmental health, or planning construction projects, understanding soil properties through testing is indispensable.

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.