The manufactured concrete products (MCP) industry has been successful in marketing and touting our products as fireproof, wind-resistant, and durable. The design community is no longer simply satisfied when manufactured concrete products show up on time at projects.
Our customers are asking more questions about quality. Producers need to be prepared for these questions when they come. Important topics such as Leadership in Energy and Environmental Design (LEED) points, sustainability, and durability are common elements in their discussion of what makes a quality product.
As production starts to wind down for this winter's slow period, this is a very good time to step back and reflect on your quality control program and to review your operating procedures.
I've spoken to many industry experts and have observed dozens of operations the last few years. From this experience, I've developed the following quality guidelines for MCP producers. It's a simple, six-step approach with which a producer may incorporate these best practices into its quality assurance program.
Step 1 - Establish a Quality Program
The first step in manufacturing any product consistently is having a documented quality assurance program. Everyone in the company should buy into the program and recognize how his job has a positive impact on the bottom line. In addition to the responsibility of meeting high industry standards, your customers and their customers expect top-notch quality consistently.
Many refer to quality control as making the product as designed, while quality assurance assures quality throughout the entire process.
In today's business climate, producers often choose to set their own internal QC requirements above and beyond those of the ASTM product specifications. This way, if a product is borderline regarding the internal QC specification, it will still exceed the ASTM standard.
This isn't something managers need to start from scratch. The National Concrete Masonry Association has developed a written approach that can easily be adopted to meet your own particular operations.
Quality assurance should be a continuous improvement process. A documented QA/QC program is highly recommended and all records should be maintained. Regular meetings with all levels of operations are helpful to show progress or regression and plans for improvement. Continue to optimize the process over time.
Step 2 - Review Raw Material Specifications
The quality and consistency of the raw materials used in manufacturing concrete is extremely important. Materials should meet relevant standards, such as ASTM. But more than just receiving a passing grade, producers should opt for ingredients that perform well in the plant's manufacturing process and environment.
The material supplier should be reliable. Its QC department should alert you of the characteristics to help you achieve your goal. It's important to monitor the quality of all materials regularly. It is much better to catch potential problems or make design adjustments before manufacturing questionable or poor quality units.
Cement is the glue that holds things together. As specified in Section 4 of ASTM C90, C936, and C1372, the cementitious materials should meet the minimum requirements of ASTM C150, C150 modified, C595, or C1157.
For quality purposes, cement should be consistent in color and have a good performance record over time. The cementitious content of masonry concrete mix designs varies by region, materials, equipment, and product type. Below are some typical products and cement contents (in percent by weight):