CP Road Map E-News: The NC2 E-News is a bi-monthly newsletter based on the Long-Term Plan for Concrete Pavement Research and Technology (CP Road Map)—a national research plan developed and jointly implemented by the concrete pavement stakeholders community. To read the CP Road Map E-News March 2016 topics, and all of the compete articles below, please click on the image to the left, or click here: http://www.cproadmap.org/publications/e-news_Mar2016.cfm.
New Moving Advancements into Practice (MAP) Brief: MAP Briefs describe best practices and promising research that can be used now to enhance concrete paving. The March 2016 MAP Brief titled “Concrete Pavement Recycling and the Use of Recycled Concrete Aggregate in Concrete Paving Mixtures” discusses the production methods, potential uses, benefits, and material properties of recycled concrete aggregate (RCA). The MAP Brief also highlights the use of RCA in concrete mixes in the U.S. and Europe and summarizes the performance of previous pavement projects that incorporated RCA in the pavement mixture. To read and download the PDF of the March 2016 MAP Brief, please click on the image below, or click here: http://www.cproadmap.org/publications/MAPbriefMarch2016.pdf.
NATIONAL CONCRETE CONSORTIUM (NCC) STATE SURVEY SUMMARIES: Member states of the NCC have the ability to poll other member states regarding specifications, materials, construction, research, or other issues related to concrete paving. This section highlights some of the questions posed and answers received through the NCC’s ListServ feature.
Addition of Withheld Water: Kansas polled the NCC group to inquire if agencies allow water that has been withheld from a mix to be added back in. Twenty-two states responded to the question and the overwhelming majority (20 states) do allow withheld water to be added back in, as long as the resulting water to cement ratio does not exceed that of the approved mix.
NEWS FROM THE ROAD: News from the Road highlights research around the country that is helping the concrete pavement community meet the research objectives outlined in the CP Road Map.
Factors Influencing the Drying Shrinkage of Concrete Pavements: This literature review examined the primary causes of drying shrinkage of concrete. The review determined that the primary mechanisms of shrinkage can be separated into three categories: plastic shrinkage, chemical shrinkage, and drying shrinkage. Numerous factors influence the severity of drying shrinkage, however, the most influential are related to the cement paste. The review also looked at the effects of other factors including aggregates, air content, curing, environmental factors, and construction practices. To access the full document, please click on image to left, or click here.
Influence of Mixing Time on Fresh and Hardened Concrete Characteristics: Most specifications place a limit of 90 minutes, or 300 drum revolution counts (DRC), between the batching and placement of ready-mix concrete. The purpose of these limitations is to maintain the quality and workability of the fresh concrete and ensure the resulting pavement or concrete product provides long-term durability.
Internally Cured Concrete for Pavement and Bridge Deck Applications: Internally cured concrete (ICC) has been identified as a promising technique for reducing early-age cracking due to shrinkage. Internally cured concrete utilizes lightweight aggregates (LWA) within the concrete mixture.
• The lab analysis compared three standard mixes and three internally cured mixes.
• The field study consisted of the construction of three test slabs.
Research Examines the Relationship Between Fuel Economy and Pavement: Researchers at the Massachusetts Institute of Technology (MIT) are investigating the interaction between a vehicle’s wheel and the pavement structure in an attempt to quantify the effect that pavement properties have on fuel consumption.
For the Long-Term Plan for Concrete Pavement Research and Technology (CP Road Map) please go to:http://www.cproadmap.org/.
To find out more about the CP Road Map, or to get involved, contact:
Steve Klocke, Program Manager, Snyder & Associates
E-mail: sklocke@snyder-associates.com | Phone: 515-964-2020
Dale Harrington, Program Manager, Snyder & Associates | E-mail: dharrington@snyder-associates.com
Sabrina Shields-Cook, Editor, CP Tech Center | E-mail: shieldsc@iastate.edu
Marcia Brink, Managing Editor, CP Tech Center | E-mail: mbrink@iastate.edu