With improved concrete overlay construction methods, transportation agencies can improve mobility, safety, and access to property.

The National Concrete Pavement Technology Center, Iowa Department of Transportation, and Federal Highway Administration set out to demonstrate and document the design and construction of portland cement concrete (PCC) overlays on two-lane roadways while maintaining two-way traffic. An 18.82 mile project was selected for 2011 construction in northeast Iowa on US 18 between Fredericksburg and West Union. This report documents planning, design, and construction of the project and lessons learned. The work included the addition of subdrains, full-depth patching, bridge approach replacement, and drainage structural repair and cleaning prior to overlay construction. The paving involved surface preparation by milling to grade and the placement of a 4.5 inch PCC overlay and 4 foot of widening to the existing pavement. In addition, the report makes recommendations on ways to improve the process for future concrete overlays.

The National Concrete Pavement Technology Center (CP Tech Center) at Iowa State University conducted a four-year, multi-state concrete overlay construction program to demonstrate and document the concept and benefits of various concrete overlay applications and provide real-world lessons. Teams of CP Tech Center I FHWA experts completed 26 field site visits in 18 states and provided workshops or technical assistance on overlay projects in six additional states. The site visits included four open house demonstration projects. A report with recommendations was prepared for each of the site visits. As a result of the site visits and recommendations, concrete overlays were either constructed or scheduled for construction in nine states, and the teams provided additional advice and assistance as requested during the course of these projects. During the site visits, workshops, project planning, and construction, the teams recognized opportunities to improve concrete overlay projects for a variety of applications, and the final report includes an overview of these lessons learned. Volume I of this final report outlines the field applications program purpose, activities, and results/lessons learned. Volume II includes copies of all documents prepared during the course of the program.

This report from the second Strategic Highway Research Program (SHRP 2), which is administered by the Transportation Research Board of the National Academies, focuses on improving the ability of highway agencies to design and construct long-lasting highway projects with minimal disruption to the traveling public.

The report describes the Virginia Department of Transportations' first modern experience with the construction of thin-bonded Portland cement concrete overlays of existing concrete pavements and with the fast track mode of rigid paving. The study was conducted in cooperation with the Federal Highway Administration (FHWA) and used a paving mixture verified in an FHWA mobile laboratory. The study showed that the fast track mode will permit lane closure times as short as 48 hours. Of special interest was the finding that adequate strength of the bond between the old pavement and the overlay is not dependent on the use of a bonding grout.

"This synthesis report will be of special interest to pavement designers, materials engineers, and other seeking information on portland cement concrete overlays placed over both concrete and asphalt pavements. Detailed information is presented on design, construction, and performance of such overlays."--Avant-propos.