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The Concrete Times Summer 2015

The CONCRETE Times • SUMMER 15 columnist - jay shilstone THERE’S A STORY BEHIND EVERY STORY THIS MONTH, JAY SHILSTONE LOOKS AT THE STORIES BEHIND THE SPECIFICATIONS AND WAXES LYRICAL ABOUT CONCRETE AND SOME WELL KNOWN PEOPLE IN THE INDUSTRY. Ja James M. “Jay” Shilstone, Jr. is the third generation of Shilstones to be involved in concrete quality control. A Fellow of the American Concrete Institute, Jay has been widely recognised as an expert in concrete quality control around the world and he is also a member of the American Society of Testing and Materials and the National Ready Mixed Concrete Association. He has been in the concrete industry for almost 40 years, with over 30 of those years involved in concrete quality control software. Jay works for Command Alkon, Inc. and is their technical specialist in the COMMANDqc quality control software program. A compelling writer, Jay is also a keen blogger and his blogsite on www. commandalkonconnect.com gets over 1000 hits per week. 10 In this day and age it seems like everything is bitesized – Chicken Nuggets, tapas, sound-bites, Vine (video-bites), memes and factoids. Everything is meant to be consumed, then discarded in an instant. Single-use plastic grocery bags seemed like a good idea at the time, until we saw thousands of them littering the road alongside a landfill. Sometimes we are so intent on getting “answers” that we forget what we truly need is an “education”. FOCUSING ON THE TREES NOT THE FOREST We get so focused on the trees that we forget about the forest. We need to not just relate the facts. We need to be story tellers. Stories come in all shapes and sizes. On the small end of the scale we have Aesop’s fables or Jesus’ parables from the Bible. On the grand end of the scale there are Homer’s epics, War and Peace and the Bible or Koran as a whole. At their most basic level stories give us context – a framework on which to hang the details. A hungry dog steals a piece of meat and runs to the riverside to eat the meat. While there he sees his reflection in the water and thinks it is a different dog with a bigger piece of meat. The dog drops his meat into the water so he can steal the bigger piece of meat from the “other” dog. In doing so he loses his own piece of meat. The moral: “He who is not satisfied with what he has may lose everything trying to obtain what he has not.” THE GRANDER END OF THE SCALE On the grander end of the scale, stories immerse us alongside the protagonists in their great adventures. Dr. Zhivago isn’t just the story of a boy growing to manhood. It is a story of humanity beset by trying times amid the beauty and harshness of Czarist Russia. This intricate novel, filled with the incomprehensible comings and goings of a multitude of characters, places the reader smack-dab in the middle of life in a location that is at times warm and bountiful, at other times starkly frozen and pristine and also at times brutal and filthy. THE EIGHTH PARA AND NOT A WORD ABOUT CONCRETE A reader caught up in this intricate story seems to feel the cold and snow of a Russian winter. So here I am in the eighth paragraph of my little “story” and so far not a word about concrete. Why am I talking about hungry dogs and Czarist Russia and not about f’c, water/cement ratio and punching shear stresses? I use these previous examples to make people aware that concrete has a story, too. Some people think the story of concrete goes back to the time of the pyramids. In my office I have a small sample of “concrete” from a pavement in Yiftahel, Israel, dating back to around 7000 B.C. I would love to know the true story behind the creation of this concrete. Sometimes people are so caught up in getting “answers” to their everyday problems that they don’t think about the stories behind the answers. Ask a group of concrete technical people what the minimum water/cement ratio is to insure complete hydration of the cement. SPECIFICATIONS WRITTEN ACCORDINGLY Most will state a figure ranging from about 0.26 to 0.28. Accordingly specifications are written that require evermonthly decreasing maximum water/cement ratios under the assumption that as long as the specified value exceeds 0.28 then all the cement will be hydrated. Wrong! There is a story behind the 0.26 water/cement ratio value. In 1949 Treval Powers authored PCA Bulletin 29— “The Nonevaporable Water Content of Hardened Portland-Cement Paste—Its Significance for Concrete Research and Its Meth


The Concrete Times Summer 2015
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