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How Do You Test Concrete Strength? 

Concrete is the most widely used building material. Ultimately, the durability and safety of every structure depends on a solid concrete foundation – which depends on being able to prove that the concrete has been properly tested, recorded and approved.  

There are a number of steps that technicians need to take to test concrete strength in both the field and the lab.

Concrete Testing In the Field

At the construction site during the pouring process, technicians will conduct field testing by sampling fresh concrete. From these samples, they will conduct various tests, including: 

  • Slump: Measures the consistency of fresh concrete before it sets to verify that the batch has been mixed properly.
  • Air: Measures the air content of fresh concrete. The amount of air is important to know as it can increase or decrease concrete strength and determine if it’s protected from various weather conditions. 
  • Unit Weight: Measures the weight of a sample of concrete to verify the mix of concrete you’re using for a specific setting. (For example, you don’t want to mistakenly pour full weight concrete on the second floor of a building and lightweight concrete on the first floor.)
  • Temperature: Measures the temperature of concrete at mixing time to inform how the concrete cures (and strengthens) later on. 

These tests are critical to capture as they all impact how the concrete strengthens over time. At this point, technicians will also cast cylinders and bring them to the lab to cure until the date of lab testing. 

Concrete Testing In the Lab

Lab testing usually happens after 3, 7 and 28 days. On those dates, the lab will test the concrete cylinders to verify they have met necessary strength requirements. 

The most typical lab test is called a compression test. A compression testing machine allows technicians to test concrete cylinders, cubes, blocks and prisms by pushing on the material until it breaks. 

Concrete strength can be tested in other ways beyond compression, depending on the specimen’s geometry and application. Other concrete strength tests and measurements include:

  • Tension: Pulling a specimen until it breaks.
  • Flexural: Bending a specimen, which produces tensile stress on the convex face and compressive stress on the concave face, until it breaks.
  • Modulus of Elasticity (MOE): Measures how much a material stretches or compresses in response to a given force.
  • Poisson’s Ratio: Similar to MOE, measures the resistance to deformation perpendicular to the direction of the load.
  • Tensile Splitting: Loading a test specimen cylinder lying on its side and splitting its diameter vertically as an indirect method of determining its tensile strength.

Conclusion 

To keep a construction project on track, testing concrete strength is crucial. However, there are many different tests and standards to follow, and the tests themselves are sensitive to human error and manual inefficiencies. 

Concrete testing software (also known as construction materials testing software) can help projects overcome these issues by automating the process from specimen identification to data collection, transfer and analysis. All to drive more accuracy, transparency and productivity in the process – and be sure the reliability of the concrete.

Want more accurate, auditable concrete strength test results? ForneyVault can help. See it in action by requesting a demo today.

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