Compatibility of Concrete Ingredients Subject of Research

A multi-year research project conducted by CTLGroup and sponsored by Federal Highway Administration (FHWA) and PCA , Identifying Incompatible Combinations of Concrete Materials, studied how the interaction between various component materials can adversely affect concrete performance. The study was initiated because of the increasing complexity of concrete mixtures for high-performance applications. New materials, new combinations, and tighter deadlines and tolerances increase the potential for incompatibility problems.

Protocols were developed to test materials for potential incompatibility in a particular combination. The research and resulting recommendations are meant to enable preconstruction testing that can reduce the likelihood of performance problems in the field. A six-page TechBrief provides a broad summary of the findings.

Volumes 1 and 2 of the full report are available as hardcopy from FHWA. Contact the FHWA Product Distribution Center by e-mail to report.center@fhwa.dot.gov, by fax to 301.577.1421, or by phone to 301.577.0818.

ASTM Reinstates Specification C 10 for Natural Cement

Recent interest in historic preservation has led to a need for natural cement for use in renovations of historic structures. Natural cements were extensively used in 19th and early 20th century construction, and many historic structures were built with these materials. However, with improved technology for producing portland cements, sales of natural cements began to decline in the late 1800s, stopping entirely by the mid-1970s.

To meet the needs of architects, engineers, and historians working on restoration projects, natural cement production has begun again in the U.S. and a specification was needed to define the product. ASTM International has reissued an updated ASTM C 10, Specification for Natural Cement, to fill that need. More.

A technical conference on natural cement will be held in April 18-20, 2007, in Syracuse, N.Y. (www.naturalcement.org). A copy of ASTM C 10 can be obtained at ASTM International’s Web site .

Specifying White Cement

A key advantage of using white cement for decorative and architectural concrete is that it provides a neutral tinting base and consistent color results. Every color option is possible with it, from pure whites to bright and pastel colors. White cement is available everywhere in North America. Although you won’t find it under a separate specification, it can be specified via a number of different standards—portland cements, masonry cements, and plastic (stucco) cements. More.

Click here for more about white cement and decorative concrete.

Q: My concrete driveway was built last year. This spring I noticed that there are areas where the broom texture has worn away and in one area the surface is rough and I can see some of the stones that I believe to be fairly deep in the concrete. What causes this and should I be concerned about the long-term durability of the driveway?

A: What you are describing may be scaling, which is a general loss of mortar from the concrete surface. This mechanism is typically caused by one of the following physical processes:

1. concrete that is exposed to multiple freezing and thawing cycles when the concrete is saturated with water


2. concrete that is exposed to deicing chemicals

In either case the concrete surface is disrupted by tensile forces that develop as the result of water near the surface which expands as it freezes. More.

Click here for more cement and concrete FAQs.

Troubleshooting: Solutions to Concrete Field Problems
November 13-15, 2006, Skokie, Ill.
This 3-day PCA course addresses real-life problems that may occur when using concrete as a building material caused by inadequacies in design, construction, and maintenance practices. More.

Get Free Admission to World of Concrete and Discount on Seminars

As a co-sponsor, PCA offers free advance registration to the World of Concrete, in Las Vegas, January 23-26, 2007. You can also get a discount on the many seminars starting on January 22.

Don't miss the seminars on Top 10 Myths of Concrete Construction and How Today's Cements Affect Concrete Properties given by PCA's Michelle Wilson.

Register Online
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For a complete listing of industry conferences, click here.

Foundation Awards Presented

The Portland Cement Association Education Foundation funds educational activities that will increase public knowledge regarding appropriate uses of cement and concrete. Subject areas of interest are Concrete Technology, Residential, Public Works, Masonry, Engineered Structures, and Cement Manufacturing. Innovative projects in other areas of cement and concrete technology are also considered.

The Foundation recently presented six graduate students from North American universities with $20,000 for research projects at PCA’s Joint Fall Meeting in September. More.

Applications are being accepted for the 2007 awards. They must be received by January 15, 2007. More.

Concrete Research Library (DVD021)

This searchable compendium includes more than 1,100 PCA concrete research reports from 1916 to 2006 on water to cement ratio and long term field performance of concrete to recent research on alkali-silica reactivity, high performance concrete, life cycle inventory, and masonry.

For more information or to order, click here.