Concrete International May 2013 No. 5 Complete Issue
Click on the cover image for the flip book version.
Assessing Aggregates for Radiation-Shielding Concrete
Petrographic examination provides an effective means to detect potentially deleterious and undesirable materials in aggregates for concrete. In this article, the authors discuss aggregates used in radiation-shielding concrete (RSC). They also cite the standards and describe the procedures for evaluating these aggregates.
Evaluation of Port of Miami Tunnel Segments
After it was discovered that the interior faces of many of the precast concrete segments produced for the Port of Miami Tunnel had not been cured per the project specifications, on-site testing was conducted. The resulting air permeability data were used to determine the effect of curing duration on the predicted carbonation rate and evaluate the service life of the affected segments. Although the analyses showed that the expected service life was reduced for the segments that had not been cured as specified, the investigators concluded that the affected segments would still meet the required service life of 150 years.
Meeting Extreme Demands
Concrete surfaces in industrial facilities may be exposed to a wide range of extreme environments, including strong acids or high temperatures. Ceratech’s activated fly ash cement concrete systems, KEMROK™ and FIREROK™, show remarkable durability in such environments.
Keeping Water Out
Two well-established companies—Portadam, Inc., and Rain for Rent—have entered into a strategic partnership to provide contractors in North America with environmentally friendly cofferdam and dewatering solutions. The article presents brief description of the companies, their partnership, and completed projects.
ACI’s New Officers for 2013
Ellis, Wood, and four new Directors elected
ACI’s Award-Winning Papers and Articles
Authors recognized with honors at the Spring Convention
ACI Expands Its Presence at World of Concrete
New features and resources added to the Institute’s booth
The Concrete Society 2012 Awards
The 44th Concrete Society Awards Dinner, the longest-running awards event in the UK construction industry, was held November 1, 2012, at the Intercontinental Hotel in London, England.
Fluid and Soil Load Combinations
Using a number of design standards as references, load combinations applicable to in-ground reinforced concrete tanks for nonhazardous liquids are reviewed. The review shows that only one of the cited standards prevents the designer from using lateral earth pressure to counteract hydrostatic pressure in the most basic load combination. The reasons for and against this requirement are discussed, along with other considerations such as tightness testing and reducing the potential for leakage.
Concrete Q & A: Sulfate-Resisting Cement and Slag
Q. We are designing a project that will be exposed to sulfates in the soil. Should our specification prohibit mixtures that combine sulfate-resisting cement and slag cement?