Delivering Durability

Concrete International, May 2007 by Brink, Marcia, Harrington, Dale, Taylor, Peter

New concrete pavement manual bridges gap between recent research and common practice

The new Integrated Materials and Construction Practices for Concrete Pavement: A State-of-the Practice Manual (IMCP Manual) (Fig. 1) is the product of a multi-year effort funded by the Federal Highway Administration (FHWA) and executed at Iowa State University's National Concrete Pavement Technology Center (CP Tech Center). The 350-page manual is a textbook, quick reference, and troubleshooting guide all in one. Readers will find straightforward information that will help them understand and use the best practices, technologies, and tests for optimizing the performance of concrete in pavements.

WHAT'S DIFFERENT ABOUT THIS MANUAL?

For one thing, it's not just for concrete experts. The IMCP Manual is written, illustrated, and designed to be accessible to a wide audience that includes:

* Design, materials, and construction engineers and technicians;

* Quality assurance and control personnel;

* Construction supervisors and inspectors; and

* Contractors.

The manual provides different levels of technical detail for different readers. Each major chapter section begins with a list of key points, followed by a discussion of the fundamentals and then more advanced information.

The format is user friendly, with a chapter index on every page, call-out boxes highlighting critical concepts and examples, cross-references for more information, and clear illustrations and examples. Some sections can also stand alone as teaching tools or references. Examples include technical sheets; troubleshooting tables; one- and two-page test protocols; and a 6-ft-tall poster folded and tucked into the back cover of the manual.

WILL IT TELL ME WHAT I NEED TO KNOW?

The IMCP Manual reflects the combined expertise and effort of several dozen field, lab, agency, and industry professionals from around the country:

* 17 authors provided "best practices" information in their areas of expertise;

* Three technical editors synthesized and organized the information;

* A team of 32 technical experts vetted two major drafts to ensure that the manual represents various industry viewpoints and readers will find the information they need to optimize concrete pavements for their geographic regions;

* Professional staff at the CP Tech Center edited and designed the book for user friendliness; and

* An experienced pavement engineer managed the overall project and guided the manual's development to produce a uniquely down-to-earth perspective of the information practitioners need.

HOW WAS IT DEVELOPED?

The IMCP Manual was originally conceived as part of the pooled-fund Materials and Construction Optimization (MCO) project initiated in 2003 by the Midwest Concrete Consortium (MCC). Now in its final year, the MCO project is a partnership of FHWA with State Departments of Transportation (DOTs), universities, and industry in 16 states.

The MCO project team focused on evaluating and implementing promising new or underused equipment and procedures for quality-control testing of concrete materials and mixture properties. The goal was to help the industry get up to speed quickly on effective, available quality-control tools.

The MCO team identified best quality-control practices and tests in all of the partner states, then took a proposed matrix of these tests on the road with Iowa State's mobile concrete research laboratory (Fig. 2). By demonstrating how to use the tests and interpret the results at pavement construction sites in each of the 16 MCO member states, the team trained field personnel across the country, effectively launching these tools into mainstream use. The team also documented improvements needed in several emerging quality-control tests and technologies.

All along, the MCO team intended to publish best testing practices. As the partners recognized the level of effort required to fill the deficit in knowledge and practice, the FHWA moved to sponsor a separate project: the development of a national training program, with its centerpiece a new manual to guide the optimization of materials and construction quality-control practices for durable concrete pavements. Late in 2003, Iowa State's team was selected and went to work on the IMCP Manual.

WHAT'S "INTEGRATED" ABOUT THE MANUAL?

Concrete pavement can be constructed with an everincreasing variety of materials-including fly ash, slag cement, chemical admixtures, or aggregates from recycled pavements-and must be expected to satisfy increasingly severe performance demands-including carrying higher traffic volumes and loads, withstanding aggressive deicing chemicals, gaining strength faster to shorten traffic disruptions, and providing quiet yet safe driving surfaces. As a result, each concrete mixture is a unique, multi-component system with complex chemistry, and is the central component of an integrated pavement project beginning with pavement design and ending months later when the pavement is opened to traffic. Further, every step in the project, almost every decision, and every change can affect the quality of the concrete.