Pervious Concrete Pavement Systems

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Sole Source Justification

Sole Source Justification is defined on this page as the process and reasoning for selecting a Single Source Contractor for the construction of Pervious Concrete Pavements.

Pervious Concrete is a non-proprietary concrete construction material. However, its physical properties, and construction methodologies are unique to the Construction Industry. Developers, and their Representatives, should review this page as part of the decision process for selecting a Concrete Contractor to construct Pervious Concrete Pavements.

There must be a legitimate reason for selecting a Sole Source Contractor.

Generally, it is in the best interest of Developers to post a "Request for Bids" in order to receive multiple bids for the selection process. This system works because the selection process is overseen by people that are competent in the knowledge and experience of the materials and practices generally used in construction. This system can also fail if the decision-makers are not familiar with the materials, or their unique construction methodologies. In these cases it can be in the best interest of the Owner/Developer to select a competent single-source contractor, and not opt for competitive bids.

                How unique is Pervious Concrete? Pervious Concrete is manufactured, and transported to the jobsite, much the same as conventional concrete. (See the General Information page to learn about the material properties.) However, not everyone has the knowledge and experience with the unique properties of Pervious Concrete, or know how to correct for load-to-load differentials. Many inexperienced Contractors may accept material transported to the jobsite, even though using it may cause the pavement to fail.

It is an Industry Standard, that the Concrete Contractor be responsible for the visual testing required for acceptance of the material on the jobsite. As a consequence, many suppliers will not deliver Pervious Concrete to a Contractor that does not have verifiable experience - because of liability issues. (See the section on Testing and Criteria for Acceptance on the Details & Specifications page.)

Because of the lack of standardized test for quality control and acceptance of Pervious Concrete, it is critical that whoever is making the decisions for acceptance of both the fresh concrete, and the finished pavement, that they are qualified to do so. The decision-maker must have adequate knowledge and experience to recognize the essential properties of Pervious Concrete, and know how to make field-adjustments (other than just by adding water to the mix).

The Pervious Concrete Industry recognizes the importance of Standardized Material Testing for acceptance criteria and is working to develop these test. The American Concrete Institute (ACI) and the National Ready Mixed Concrete Association (NRMCA) have developed "guidelines" that can be used, and the American Society for Testing and Materials (ASTM) formed a new subcommittee on Pervious Concrete in December, 2006.

The NRMCA has developed a program to train, test and certify those individuals wishing to become involved in the construction of Pervious Concrete Pavements. The NRMCA Program is the only nationally-recognized program that certifies contractors based on training and experience. There are two classifications of Certification. To become Certified as a Technician, one only has to sit for a one-day class, and pass the exam with a score of 70 or above. (No experience is required.) In order to be Certified as a Craftsman, one must also have at least 1500 to 3000 hours of experience (depending on a proficiency exam). Only a Certified Craftsman has the knowledge and experience to qualify as a crew leader where multiple-load projects are being constructed.

Contractor Experience: Many State Agencies have opted to Certify Concrete Contractors as "Installers" after having completed from one to ten projects. This is generally not enough experience to qualify for large projects. In many cases, one project can be completed in just one day. One day's experience is not enough. Even ten project/days may not be enough if all projects were small. The NRMCA recommends from 1500 to 3000 hours to be Certified as a Craftsman. It is to the best interest of everyone that only NRMCA Certified Craftsmen be employed as crew-leaders for multi-load projects.

If the Developer is planning to use pervious concrete pavements to achieve credits for LEED Certifications, then it is important to recognize the need for someone with knowledge and experience as a Team Member on how these systems can be designed to comply with the LEED requirements.

Specialized Tools are also a requirement for constructing Pervious Concrete Pavements. Many of these tools are not available on the open market (such as Glaspey-Rollers) and must be copied, and built, by the Concrete Contractor. Not all Concrete Contractors will have the knowledge, or experience, to develop the necessary tools, and as a consequence, may try to construct the pavements without them. The tools used for conventional concrete construction are not acceptable for constructing Pervious Concrete pavements. If the Owner/Developer, or their Representatives, are not aware of the special tool requirements, then they should demand that only NRMCA Certified Craftsmen be used. All Certified Craftsmen already have the tools, and know how to use them. (See photographs of some of these tools on the Pictures page.)

In order to protect the best interest of the Owner, only a Concrete Contractor employing NRMCA Certified Craftsmen, or who have retained a Certified Craftsman, should be contracted to construct projects where more than one truck-load of material is to be used. The Owner/Developer, or their Representative, may wish to Sole Source Contract with a Concrete Contractor that has employed NRMCA Certified Craftsmen.

Magruder Construction has three employees that are NRMCA Certified Craftsmen, and have the Specialized Tools.