Types of Mortar Testing and When They’re Necessary

Several different tests are needed to estimate the stability and strength of a structure, from the soil it will stand on to the bricks or concrete that will form it. But what about mortar, the material that binds it all together? There are a variety of ways to perform mortar testing, many of which are similar to how you would test aggregates, concrete or cement. In this blog, we will learn about the types of mortar testing are needed for a strong foundation.

Types of Mortar Testing: Is It Necessary?

While there are ASTM methods specifically designed for masonry mortar testing, there is not a code requirement for testing mortar. Neither the International Building Code (IBC) nor the Masonry Building Code call for mortar testing on job sites or in labs. Some specifiers will still call for mortar strength testing, so it can be performed on a case-by-case basis. Mortar may only play a small part in contributing to structural capacity, but it’s still important to determine whether it meets the physical property requirements of a project, including strength. This is where compressive strength testing becomes crucial, as it helps ensure that the mortar meets the necessary standards.

Types of Mortar Testing

You can perform several tests on both plastic and hardened mortar to find the ideal mix ratios and strength. Here are some test methods:

– Consult ASTM C 780 for detailed instructions.
– This standard outlines the specifics of each test.
– It helps you understand a mortar sample’s physical properties.

Air Content

Air content tests are commonly specified testing procedures for concrete and cement in areas that are prone to frost — they can also be specified for mortar. Repetitive tests using pressure meters or “roll-o-meters” help determine if air content levels change due to mixing consistency and mixing time in order to find the ideal level of air content both in the field and in the lab.

Board Life

Board life is a crucial form of the types of mortar testing. It shows how long mortar is usable after removal from the mixer and placement on a mortarboard. Mortar loses moisture and stiffens in open air, so quick placement is essential for proper bonding. This test not only determines the time frame but also checks if the mortar will be acceptable once hardened. If it’s too stiff, it won’t work.

Compressive Strength

Use standard methods to perform compressive strength tests on hardened mortar. These tests help determine the load a sample can bear. They are best suited for laboratories because field testing may yield less accurate results.

Consistency

Consistency testing identifies variations between mortar mix batches, in both materials and mix time. Use mortar testing equipment, like a mortar penetrometer, to determine consistency based on penetration depth into the sample. Inconsistent batches don’t necessarily mean the materials are bad. Instead, they suggest poor control during batching, mixing, and testing.

Mortar-Aggregate Ratio

This test method helps determine whether cement, sand, and water are added properly and consistently to each batch of mortar, a bit like the consistency test. But, while the tests might be similar, mortar-aggregate ratio testing is performed solely in a laboratory, after mortar mix samples are obtained from a job site and sent in to be measured.

Water Retention

Water retention tests measure the plastic life of mortar. The longer the plastic life, the more time a mason has to lay and adjust the mortar before it hardens. These tests are performed in a laboratory.

Mortar testing is crucial for quality control in the construction industry, especially for masonry projects. Mortar, a mix of cement, lime, sand, and water, acts as a bonding agent for materials like bricks and stones. Testing ensures mortar has the needed strength, durability, and compatibility with masonry units. This contributes to the structural integrity and longevity of buildings.

1.7 1. Types of Mortar Testing for Masonry:

Conduct several tests on mortar to assess its various characteristics. One such test, among the many types of mortar testing, involves examining hardened masonry mortar to identify its properties and proportions. Some of the primary tests include:

• Compressive Strength Test: This is the most critical test for mortar. Prepare and cure mortar samples under controlled conditions. Then, subject them to a compressive load until failure. Calculate the compressive strength, which should meet the project’s specified requirements.
• Flexural Strength Test: This test measures the tensile strength of mortar. It helps in understanding the load-bearing capacity of the mortar under bending stresses.
• Bond Strength Test: The bond strength test assesses the adhesion of mortar to brick or stone. A strong bond is essential for the structural integrity of masonry work.
• Water Retentivity Test: This test determines the ability of mortar to retain water under suction, which is crucial for hydration and bonding strength.
• Setting Time Test: The setting time, both initial and final, is measured to understand how quickly the mortar sets. This has implications for workability and the speed of construction.
• Air Content Test: This test measures the amount of entrapped air in the mortar, which affects its durability and resistance to freeze-thaw cycles.

2. Importance of Using Different Types of Mortar Testing for Masonry:

Using different types of mortar testing is vital for several reasons:

• Quality Control: The types of mortar testing ensures that the mortar used in construction meets the required standards and specifications. Use masonry cement in these tests to ensure the mortar meets standard specifications.
• Durability and Strength: Proper testing helps in verifying that the mortar will provide the necessary strength and durability to the structure.
• Compatibility: Tests like bond strength ensure that the mortar is compatible with the bricks or stones, which is essential for the longevity of the masonry.
• Compliance with Regulations: Many regions have building codes and regulations that mandate certain standards for mortar. Testing helps in ensuring compliance with these regulations.

3. Challenges in Mortar Testing:

Using the types of mortar testing is challenging due to variable raw materials, mixing methods, and curing conditions. Chemical analysis helps by examining hardened masonry mortar. It provides quantitative and qualitative descriptions of the binder and estimates the binder-to-sand ratio. Consistent sample preparation and controlled curing conditions are essential for reliable results.

Conclusion:

In conclusion, mortar testing is essential in the construction industry. It ensures the mortar used in masonry work is high-quality, durable, and compatible with construction materials. This process plays a significant role in the safety, stability, and longevity of structures. Therefore, mortar testing is indispensable in building.

Find Mortar Testing Equipment at Certified MTP

On top of mortar testing tools, Certified Material Testing Products carries several kinds of cement testing equipment to help you find the optimal mix for any project including all types of mortar testing. They also offer ASTM C67 methods for sampling and testing brick and structural clay tile, which are essential for selecting replacement mortar and identifying masonry deterioration causes. Browse our cement and aggregate testing equipment today to outfit your testing laboratory or job site with all the necessary tools to create strong, consistent materials. View the full line of Soil Testing Products and Soil Moisture Testing Equipment, especially the popular Aggregate/Sand Moisture Measurement System.

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