From layers of soils and cement to forged beams and walls, it is critical to maintain support and uphold structural integrity. Construction materials testing (CMT) is an important practice that allows builders and site owners to identify potential deficiencies before committing to a project.
Testing is essential in maintaining a structure long after it has been erected. The long-term stability of construction is best determined through routine checks and maintenance. For existing structures, there are two common testing options:
- Invasive testing
- Non-invasive testing (also known as non-destructive testing)
The difference between them is inherent within their names. Invasive tests run a risk of causing damage or destruction to portions of the existing structure, and as a result require repair or replacement of the damaged portions. On the other hand, non-invasive tests allow for structures to be unharmed and undamaged during routine testing and assessments.
Some examples of non-destructive testing equipment include the following:
Ground Penetrating Radar (GPR)
Ground Penetrating Radar accuracy has come a long way from the fuzzy lines on NCIS and CSI. The technology behind these machines has advanced to the point where their real-world application can save thousands or millions in structural integrity testing.
Whether finding voids in foundations or fractures within Rebar, GPRs can determine whether a structure has maintenance required damages without the need for any invasive actions. Though the sci-fi renderings may be a bit overblown, the ability to visually detect defects, deficiencies and obstacles has become quite precise.
In addition, GPR can also be used effectively to locate wires, plumbing and hidden conduit without the need for exploratory drilling.
Rebound hammers have been around since the 1950s. Through the use of impact and rebound action, they can be used to non-invasively determine the hardness of a variety of materials, concrete being the most common. For practical purposes, we will focus our thoughts specific to concrete testing equipment.
When the plunger of a rebound hammer is pressed against a smooth surface of the concrete, the spring-controlled mass rebounds. The amplitude of such rebound depends upon the surface hardness of concrete. The surface hardness and therefore the rebound is directly related to the compression strength and hardness of the concrete. The data collected is a non-destructive way to determine this strength without taking core samples.
Rebound tests also provide data that shows the overall strength of concrete pours, concrete strength uniformity, and the strength of the concrete over time through varied testing. Testing can be conducted directly after curing or years in the future. The tests ensure the highest quality concrete strength for the costs, leading to savings per cubic yard poured.
Ultrasonic testing (UT)
Ultrasonic Testing Equipment is a family of non-destructive testing equipment based on the production and evaluation of ultrasonic waves in the object or material tested. The returned waves are used to develop visual and critical data representations of material structure, uniformity, deviations or damage.
Why a uniform testing method, Ultrasonic Testing is not limited to a select medium. From metals, to concrete, to plastics, to epoxy, UT is a reliable option for testing materials in a non-invasive manner. Most UT devices consist of many separate units. These can include pulsers and receivers, transducers, and display monitors. The components included for the project depend on the type of UT that the inspector is performing.
Ultrasonic testing has proven especially useful in finding micro-fractures and cracks in robust materials that hold heavy loads. Large load-bearing beams and posts are both cumbersome to extract, and in need of regular strength tests. UT equipment provides a perfect solution for testing the surface and interiors for wiring, cracking, structural deformity or any other signs of weakness that would warn of weakening.
With so many methods and forms of Non-Destructive Testing Equipment available, there are always specific tools available to specific material applications. While these three examples are only a small sampling of the many forms of non-invasive equipment, they are great examples of the diverse tools available. The varied equipment ensures safe structural development and the ability to maintain stability in a non-destructive manner. As a result, it is imperative for all builders, developers and maintenance supervisors to become familiarized with the material and costs saving tools classified as Non-Destructive Testing Equipment.