There are a wide variety of products produced by Rinker Materials and the specific quality control processes for each are different. However, the items discussed below generally apply to all products and are intended to illustrate the range of items included in quality control processes for reinforced concrete pipe, reinforced concrete box culverts, manholes, and other precast concrete products. Where appropriate, specific tests or specific products are discussed.
Calibrations are performed on equipment to ensure it is performing as intended and within specified tolerances.
Certifications and/or test reports, as required, are collected and checked for the materials used in the production of our products.
Mix designs are developed internally for each plant to produce quality products that meet the required specifications using locally available materials. Concrete batches are regularly verified by checking the actual batched quantities against the approved mix design. Concrete testing continually verifies that the mix design requirements are met.
Forms are visually inspected before and after each use.
Forms and molds being put into production at a facility for the first time are thoroughly checked prior to use whether they are new or being transferred from another operation.
In facilities utilizing the packerhead process of pipe production, the packerheads are routinely checked for wear and the diameter of the packerhead is measured at the start and end of each production run.
Joint forming equipment, especially for gasketed joints, undergoes precise dimensional checks to ensure a good fit and the best performance.
For machine made products, such as pipe and boxes, a check is done on the first reinforcing cage and additional cages are checked at the start of new shifts or if any components or settings are changed in the production process. Before a cage run begins, the first cage is placed in a mold and verified to have proper reinforcement cover, chair size, and length.
Precast products are individually checked by QC personnel for proper reinforcement and dimensions, including any embedded items, block-outs, or handling devices.
Additionally, throughout the course of manufacturing, each product receives routine visual inspections by the personnel responsible for the various operations to make the product.
Test requirements vary depending on the mix type being used and the product produced. Each wet cast mix is tested at least once each day it is used. This may include slump or slump flow testing, air content tests, unit weight tests, temperature, and compressive strength testing.
For machine (or dry) cast production methods, concrete cylinders are made at least weekly following the procedures in ASTM C497, which differ from the standard cylinder molding procedures found in ASTM C31, and produce specimens for compressive strength testing that are more representative of dry-cast manufacturing processes.
Additionally, a minimum of one concrete absorption test is performed each year for each mix design used.
Steam curing allows elevated temperatures to be used to achieve an accelerated curing timeline and provide moisture to the fresh concrete. Steam curing is one of the tools that helps us achieve design strengths in excess of 5,000 psi in just a few days. This allows quicker turnaround times, as products can be shipped more quickly after production.
For products that utilize accelerated curing procedures, temperature logs are routinely checked to ensure the heating rate and maximum temperature requirements are being met. For products that are cast outdoors or do not utilize accelerated curing, traditional curing methods to prevent rapid moisture loss and maintain proper temperatures are implemented.
All products produced in a day are visually inspected by qualified QC or production personnel to check for any defects that may have occurred during production or handling. Dimensional checks are performed regularly throughout the production day and all embedded items and block-outs are checked for size and location. For concrete pipe and manholes with gasketed joints, the spigots and bells are checked, as required, using a Go/No-Go gauge to confirm the dimensional requirements of the joint have been met.
A variety of tests are available for concrete pipe and precast products to test different properties of the finished products, depending on the needs of the project.
For concrete pipe, common tests include the Hydrostatic and Three-Edge Bearing Tests.
Hydrostatic testing is performed, upon request, to verify the watertightness of joints and sometimes the barrel, depending on the test setup. There are multiple test setups that may be used for joint testing depending on the project requirements, which can include straight or deflected alignments, internal or external joint-only tests, and off-center joint testing.
The Three-Edge Bearing Test is a proof of design test that directly tests the strength of round, arch, and elliptical concrete pipe and it is performed regularly as direct product assurance. The test measures the load required to produce a 0.01-inch crack (approximately 1/5th the thickness of a dime) in the pipe specimen and can also be used to test the ultimate strength of the pipe. This test not only verifies that the completed pipe meets the requirements of applicable specifications, but also facilitates use of indirect design methods and is proof of the inherent strength in reinforced concrete pipe.
After production and testing are complete, the products are stored until shipment. Each plant has procedures in place to prevent damage during handling and storage, including maximum stack height policies for each product made at that facility. Prior to shipment, strength criteria specific to each product must be met before the product is allowed to be shipped. As a last check, a Final Inspection is performed on all products before leaving the plant, which includes a visual inspection of the products and checking how the products have been loaded and secured for shipment.
Many of processes described above are required by nationally recognized standards. There are many organizations that develop standard specifications and two of the most common for concrete pipe and precast concrete products are ASTM International and the American Association of State Highway and Transportation Officials (AASHTO). Additionally, state highway agencies and local municipalities often have specific requirements for products used in their areas and there may be additional special requirements for specific projects. The internal quality systems at Rinker Materials are built around consistently meeting or exceeding the national, local, and project specific requirements for quality.
For a list of common national standards for reinforced concrete pipe, click here.
Along with the requirements of national and local standards and any plant inspections or audits that may be performed by local agencies, many of Rinker’s facilities participate in one or more voluntary third-party quality assurance programs. One of these programs is called the Quality Cast (QCast) Plant Certification Program and is administered by the American Concrete Pipe Association (ACPA). Plants must meet the requirements of ACPA’s Plant Certification Manual and demonstrate compliance through third-party audits. Participation in programs such as these ensures that a plant is meeting nationwide standards for quality and adds an additional check on quality control procedures.
Concrete pipe and precast concrete products made by Rinker Materials are held to rigorous quality standards. Some of these are required by national standards, while others have been developed as best practices through experience. Some of these procedures can trace their roots back almost 100 years, such as with the Three-Edge Bearing test, while others are still evolving as manufacturing processes improve and project requirements change. Rinker Materials is dedicated to continually improving and staying up to date with these changes, while providing time-tested, quality products to meet your infrastructure needs.
