This article original appeared in Precast Today’s Q2 2023 edition.
By Scott Crumpler
A quality control department is an important element in any precast concrete manufacturing operation.
Considering the potential pitfalls that can affect a plant due to faulty or out-of-specification product, it quickly becomes clear that an effective, well-trained and well-equipped QC team is not just necessary but essential.
A robust QC department develops over time. How much time it takes depends on a few factors: the complexity of the product line, the demands of state and local oversight elements and the plant’s dedication to being compliant.
Along with a plant’s product line, its manufacturing styles affect the necessary elements needed to get a QC department up and running.
Every plant requires the ability to make and evaluate concrete test cylinders. That is the industry standard to measure the effectiveness of our design and batching operation.
This process drives the need for cylinder molds and lids, wheelbarrows, scoops and a place to store the fresh cylinders overnight. The next morning, the molds are stripped, requiring a stripping tool and a hammer. Cylinders not tested that day for overnight strengths need to be stored in an environment consistent with how the plant’s products are stored, most commonly storage racks or open-faced cabinets.
Compression tests can be done internally or subbed out to a third-party lab, but that can get expensive over time.
For a dry cast operation, cylinders are still needed, but the process and equipment are different. A vibrating table is necessary to properly compact the low slump concrete into a cylinder mold along with weighted discs to help consolidate the concrete. The rest of the process, including compression testing, is the same as for wet cast cylinders.
The other essential element of concrete testing is air testing. Control of entrained air in concrete is critical to success. It is essential that every
QC department has the equipment to perform this test. This test is something that must be done onsite at the mixer and is not an element that can be sent off to a third party.
Other tests include:
- Concrete temperature
- Ambient temperature
- SCC slump flow and VSI testing
Slump tests for standard slump concrete
Unit weight tests can be performed with an air pot and a scale.
Other advanced SCC testing includes:
- J-ring tests.
- Static segregation tests on initial qualification, which is requested by many state departments of transportation. Equipment for this can be shared or borrowed and need not be an investment.
Setting aside the proper amount of space to perform these tests is important, too. Space produces inconsistent results. Develop a dedicated area for the QC department to do its job. Work toward freeing them from the elements. Provide good lighting, electricity for compression testing and water for cleaning equipment.
And this is just to get started.
Once up and running, the No. 1 role for a good QC department is to properly document every process. A clean, dry, secure space is required to perform the documentation and preserve it in a way that is easily accessible.
Later on, it might be necessary to look for one document among countless created. But if you don’t know how to find that one record, it can mean starting over.
Like all departments within a precast concrete facility, the most valuable resource to any QC department is people. All of the equipment, sound processes and procedures available lose their worth without trained staff to effectively follow those procedures put in place.
Whether it is one person whose part-time duties include QC functions or a team of professionals who work together, those people must be properly trained to perform the tasks. That means training for, taking and passing the requisite exams to achieve certifications necessary to be compliant with local, state and national oversight organizations.
As time goes on and a plant grows, a QC staff should grow right alongside the production crew. Keep the number manageable, but ensure there is enough time in each day to cover the mandatory pre- and post-checks, trailer checks and the fresh and finished concrete testing.
Ensure the department has the time to document the results of each day’s work, whether with paper files, computer documentation or a comibination of both.
No matter a facility’s size, the essential elements of strong quality control are the same: Trained and willing people, equipment, space and time.
Empower the team and provide the time and the tools it needs to keep the plant in compliance, to help keep the production team focused on doing the right things the right way and be relentless in their pursuit of perfection.
Scott Crumpler is the senior manager of quality assurance/quality control at Concrete Pipe & Precast.
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