Latest Edition of National Concrete Consortium Newsletter Now Available Online

The Summer 2020 newsletter of the National Concrete Consortium includes the following items:

• Moving Advancements into Practice (MAP) - Brief on Development of an Improved Design Procedure for Jointed Unbonded Concrete Overlays on Concrete or Composite Pavements

• FHWA Concrete Clips - Curing and Internal Curing

• Time-Lapse Infrared Thermography Applied to Concrete Bridge Deck Inspection Surveys - The Federal Highway Administration mandates that all [bridge] structures in its inventory are to be inspected every two years. Consequently, deck surveys are conducted to identify unseen damage within them. A significant number of bridges in Virginia have concrete decks with an overlay. Methods commonly deployed on these decks are limited in the quantitative results they can provide. To overcome these limitations, an improved method of applying infrared thermography using time-lapse technology is introduced. Following a simulated parametric study, a time-lapse infrared thermography data collection system was acquired along with a basic program to analyze the data qualitatively. A novel physics-based program was also developed to analyze the data quantitatively.

• Investigation into Shrinkage of High-Performance Concrete Used for Iowa Bridge Decks and Overlays - Phase II Shrinkage Control and Field Investigation - This Phase II research project on the shrinkage behavior of high-performance concrete (HPC) used in Iowa bridge decks and overlays evaluated several concrete mixes, building off or modifying mixes developed in Phase I. Based on shrinkage behavior and mechanical properties, the mixes studied in Phase I were characterized as having either high, medium or low cracking potential. In this Phase II study, three concrete mixes (Mixes 6, 8 and 2, characterized in Phase I as having high, medium and low cracking potential, respectively) were selected for further investigation. The selected mixes were modified using three shrinkage control technologies: shrinkage-reducing admixtures (SRAs), cementitious materials (CM) and internal curing (IC) agents, respectively.

• Development of Rapid PCC Pavement Repair Materials - Since pavement repair and construction represent a significant percentage of federal and state funding, new materials were investigated to reduce cost and generate a more resilient material. The goal of this project was to develop cost-effective, high-performance concrete materials for rapid pavement repair while minimizing environmental impact. An experimental study was conducted to investigate sustainable concrete with recycled concrete aggregate (RCA), lightweight aggregate (LWA) and other materials to be used in rapid full-depth repair. To minimize cracking at an early age, internal curing (IC) was adapted with the RCA and LWA. RCA and LWA are viable and practical ways of producing rapid-repair concrete with less drying shrinkage.

• Development of Improved Guidelines and Designs for Thin BCOA - This report summarizes the investigations undertaken by the University of California Pavement Research Center between 2014 and 2017 to develop recommendations and guidance on the use of thin bonded concrete overlay of asphalt (BCOA) as a rehabilitation alternative for California based on the adoption of, and improvements to, the technology developed in other U.S. states. The main tasks of the project included (1) laboratory testing of four rapid-strength concrete mixes and a number of concrete-asphalt interfaces, (2) evaluation of the construction of a full-scale test track, (3) monitoring of the structural and hygrothermal responses of six thin BCOA sections to the ambient environment, (4) accelerated pavement testing with the Heavy Vehicle Simulator (HVS) on 11 thin BCOA sections, (5) finite element method modeling and (6) development of a set of recommendations for the design and construction of thin BCOA pilot projects in California.

Click here to access the newsletter which includes links to each of the above reports.