A Progress report

At the Summer Board meeting in Mt. Hood, the Board of Directors allocated funds from the Education and Research Fund for an in-depth study of cold weather and how it affects the concrete mixes our members typically use. Following a series of physical meetings and conference calls as well as idea refining through email, the committee devised a program that it felt was best to put this money to use.

Early in the process, the committee decided that our program and testing should be thorough and independent. To this end we have employed the services of Brad Barnes, P.E., as our project coordinator and Master Builders Technologies (MBT) of Beechwood, Ohio as the testing laboratory. Master Builders is a worldwide manufacturer of specialty concrete products and admixtures. Our technical associate at MBT, Joe Daczko, has already been invaluable in facilitating our work. They have made their facility, which includes industrial-sized refrigerated rooms, available to us through Rick Buccini at Osborne Ready Mix of Medina, Ohio.

Currently, we are in the process of testing 44 different mix designs ranging from a 5- sack, Type-I cement mix with no accelerator to a 6.5-sack, Type-III cement mix with water reducer and 1% calcium, and many variations in between. Each type is mixed by hand and checked for slump (6-7”), weight, and air content (6%). Each batch is then placed in cylinders (16 per mix batch) and loaded into the refrigerated rooms. Temperature measurements begin immediately, using the Con-Cure System, provided at a steep discount by John Gnaedinger of Con-Cure Corporation. Compressive strength and its relationship to time and temperature is measured over a 28-day span. These measurements, when plotted with the proprietary software, develop a kind of data known as a maturity curve. This type of testing is not new, but the equipment and technology are state of the art. There will be thousands of measurement taken and plotted, far too many to explain in a short article, but we hope to have important conclusions to share soon. In all there will be over 700 cylinders cast and broken, consisting of over ten cubic yards of concrete.

OK, “so what” you say? “We don’t care about laboratory concrete, we care about real walls!”

The next step will be undertaken in the yard of Osborne-Medina Concrete in full-scale walls poured by Scott Smith of Modern Poured Walls and Frank Ramey of Tri-County Excavation. They will be pouring a wall headed off into several different compartments, using different mixes typical to their area. Each section will be monitored with the Con-Cure Meters, and then core-drilled for cylinders that represent the real world.

The lab work will tell what these mixes are capable of. The “yard” test will show us what is really happening “out there”. The combination of these results should be able to give the CFA members a very impressive working chart showing, in general, how they can expect mix designs to perform in walls under different conditions. If you are in an area that has a really critical inspector, we will eventually be able to set you up with the Con-Cure System and directions on how to test your own local materials. We will get this info out to you as soon as we can digest it. Your earliest source may be the CFA web Site.

YOU CAN HELP!

You can help us move our effort forward in two ways:

1) We are continuing to develop field data using the HOBO Data-Loggers as was performed last winter. This system can provide data similar to that of Con-Cure system on a smaller basis. Several CFA members are measuring temperatures in their walls using the HOBO system and our CFA technical director Jim Baty is coordinating the effort and information. If you are interested in helping with some real world testing of your own, please contact Jim.

2) To help us make best use of the information we are gathering a short questionnaire will be sent to all members in the coming weeks. PLEASE fill this questionnaire out and fax your answers back to the CFA headquarters at 319-895-8830. Your answers will allow us to develop further focus to our efforts.

If you bump into any of the following people between now and the next report, give them a big thank-you! This committee has really been hard at work for the CFA members.