A two-course bonded technique that has evolved from the continuing national and local interest in bridge deck durability was used in June 1974 to construct six bridge decks in Virginia. During the construction, which was the first phase of a five-year study on the construction, condition and performance of two-course decks, detailed observations were made of the activities used to construct the six two-course decks and two conventional single-lift decks, and data concerning the several concretes utilized in the construction of the decks were recorded. Based on comparisons of two-course and single-lift construction techniques the following conclusions are made. An overlay should be placed not sooner than two days after a base layer is placed. Light sandblasting of the base layer removes laitance that might adversely affect the bond between the base layer and overlay. A bonding layer of cement slurry should be broomed onto the base layer not further than 10 feet (3 meters) nor longer than 15 minutes ahead of the overlay placements. The same depth of clear concrete cover above the top reinforcing steel resulted from the two-course construction as from the single-lift technique. Using conventional equipment selected by the contractor, the construction activities proceeded in an orderly and satisfactory manner and coefficients of variation for the time intervals required to install the base layers and the overlays are comparable to values representing excellent control for single-lift construction. Although a 7-yd 3 (5.4 m3) truckload of concrete was screeded over 3 1/2 times as much surface area for an overlay as for a conventional single-lift deck, the average duration per truckload between the initial depositing and the completion of the screeding activity on the wearing surface was approximately the same in both the two-course and single-lift techniques. Not including texturing and curing activities, the average man-hours required to install concrete in the separate layers of the two-course decks was 33% greater than for conventional single-lift decks, but in terms of project days required for construction the two-course and single-lift techniques are equivalent. The total additional cost of the two-course technique is approximately 5% of the cost of the bridge superstructure. Three overlay concretes were selected for use as wearing courses on the two-course concrete decks on the basis of their protective qualities. A broad range of handling characteristics is represented by these concretes, which included a latex modified concrete, a high quality PCC, and a wire fiber reinforced concrete. The differences in these wearing course concretes did not significantly affect the placement activities, other than the batching, during their respective installations. In general the decks constructed by the two-course technique are equivalent to those resulting from conventional single-lift construction, however these successfully installed special wearing course concretes offer improved potential for deck performance.

This report presents the findings from a six-year study of two-course bonded concrete bridge decks constructed in Virginia. Each of three special portland cement concretes was applied as an overlay, or wearing course, on two experimental spans. The overlays were a latex-modified, a low-water/cement and a wire-fiber concrete. Two spans constructed by a conventional single-lift technique on nearby structures with ordinary concrete served as controls for the study. The report summarizes the evaluation of the construction, concrete properties, condition, and performance of the eight study spans through 1980. The condition and performance of the study spans warrant the use of two-course bonded bridge deck construction in four primary applications cited in the recommendations of the report. The latex-modified and low-w/c concretes exhibited improved resistance to chloride ion penetration as compared to ordinary concrete, but the wire-fiber concrete did not. Suggestions are made concerning a quality assurance program for the latex-modified concrete and a program for monitoring such installations to determine the particular conditions that may predispose them to cracking.

Presented in this report is information concerning the characteristics of the concretes used to construct six experimental two-course bonded bridge decks in Virginia. The quality of the overlay concretes produced under standard specifications supplemented with special contract provisions is described. Recommendations are made concerning the attainment of desired cover depths over the topmost reinforcement and the attainment of adequate consolidation in the overlays. The several procedures that have been used to compare the condition of the two-course decks with that of conventional, single-lift control decks are discussed, and it is concluded that the two-course decks indicate a greater potential for satisfactory performance. Determinations of future performance will be based on comparisons of data from tests as visual surveys and soundings, chloride analyses, electrical potentials, sonic pulse velocities, and skid resistance of the decks.

Over 140 experts, 14 countries, and 89 chapters are represented in the second edition of the Bridge Engineering Handbook. This extensive collection highlights bridge engineering specimens from around the world, contains detailed information on bridge engineering, and thoroughly explains the concepts and practical applications surrounding the subject. Published in five books: Fundamentals, Superstructure Design, Substructure Design, Seismic Design, and Construction and Maintenance, this new edition provides numerous worked-out examples that give readers step-by-step design procedures, includes contributions by leading experts from around the world in their respective areas of bridge engineering, contains 26 completely new chapters, and updates most other chapters. It offers design concepts, specifications, and practice, as well as the various types of bridges. The text includes over 2,500 tables, charts, illustrations, and photos. The book covers new, innovative and traditional methods and practices; explores rehabilitation, retrofit, and maintenance; and examines seismic design and building materials. The second book, Superstructure Design, contains 19 chapters, and covers information on how to design all types of bridges. What’s New in the Second Edition: Includes two new chapters: Extradosed Bridges and Stress Ribbon Pedestrian Bridges Updates the Prestressed Concrete Girder Bridges chapter and rewrites it as two chapters: Precast/Pretensioned Concrete Girder Bridges and Cast-In-Place Post-Tensioned Prestressed Concrete Girder Bridges Expands the chapter on Bridge Decks and Approach Slabs and divides it into two chapters: Concrete Decks and Approach Slabs Rewrites seven chapters: Segmental Concrete Bridges, Composite Steel I-Girder Bridges, Composite Steel Box Girder Bridges, Arch Bridges, Cable-Stayed Bridges, Orthotropic Steel Decks, and Railings This text is an ideal reference for practicing bridge engineers and consultants (design, construction, maintenance), and can also be used as a reference for students in bridge engineering courses.

The Concrete Construction Engineering Handbook, Second Edition provides in depth coverage of concrete construction engineering and technology. It features state-of-the-art discussions on what design engineers and constructors need to know about concrete, focusing on - The latest advances in engineered concrete materials Reinforced concrete construction Specialized construction techniques Design recommendations for high performance With the newly revised edition of this essential handbook, designers, constructors, educators, and field personnel will learn how to produce the best and most durably engineered constructed facilities.