Concrete International August 2014 No. 8 Complete Issue
Click on the cover image for the flip book version.
Mixing, Placing & Curing
Durable Concrete with Modern Air-Entraining Admixtures
Current recommendations for air contents are based on research completed in the 1950s with mixtures that contained a single type of air-entraining admixture and test methods that do not match modern standardized tests. The work presented in this article investigates the fresh and hardened air void parameters and the cyclic freezing-and-thawing durability for mixtures with some of the air-entraining agents, various water-cement ratios, and combinations with mid-range water-reducing admixtures used to produce modern concrete pavements. Recommendations are made for the required air content and hardened air void system characteristics in such mixtures.
We Must Correct the Misconceptions about Sustainability
In the winning entry of the 2014 ACI Young Professional Essay contest, the author argues that actions taken to meet the short-term goal of rapid construction can have long-term consequences. While big steps have been taken to improve the sustainability of concrete construction, more emphasis should be focused on one of the key factors hindering us from being more sustainable: assuring the performance and longevity of our concrete structures. A major part of this emphasis should be educating every person involved with concrete construction.
A Low Temperature Rise Mixture for Mass Concrete
Temperature rise was evaluated for two comparable batches of concrete produced with typical proportions of aggregates. While the cementitious material in one batch consisted of portland cement and Class F fly ash, the cementitious material in the second batch consisted entirely of a liquid-activated Class C fly ash system meeting the performance requirements of ASTM C1157/C1157M-11, “Standard Performance Specification for Hydraulic Cement.” The more conventional binder system resulted in a much greater temperature rise than the liquid-activated Class C fly ash system. Thick concrete elements were modeled to determine how the binder systems would affect construction of common structural elements.
Plate-Breaking and Stepping-Stone Project
The authors describe a therapy program that helps people find the broken pieces in their lives while making something beautiful and useful out of what they have had to face. Concrete is used in the final step to hold everything together.
ACI’s Excellence in Concrete Construction Awards
New program will recognize innovation around the globe
The Concrete Research Network
An industry collaboration powered by the ACI Foundation’s
Concrete Research Council
2014 PCI Sidney Freedman Craftsmanship Awards
The Precast/Prestressed Concrete Institute (PCI) recently announced the winners of the third annual Sidney Freedman Craftsmanship Awards competition. Three projects and PCI-certified plants were recognized for excellence in manufacturing and craftsmanship of architectural precast concrete and glass fiber-reinforced concrete (GFRC) structures and elements. The overall winner was Willis Construction Co., Inc., for its production of GFRC panels for the Broad Museum, Los Angeles, CA. Two honorable mentions included Gate Precast Company for producing a monolithic steeple for the LDS Temple in Davie, FL; and Béton Préfabriqués du Lac for its role in the restoration of St. Mary’s Hall on the campus of Boston College, Chestnut Hill, MA
The Inaugural CRSI HONORS Program
Recipients awarded for leadership in project achievement and technology
Concrete Q & A: Mixture Design and Strength Submittals
Is there an ACI document that states that the
Licensed Design Professional must review mixture
design and strength test data?