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The Concrete Times Summer 2015

The CONCRETE Times • SUMMER 15 monthly columnist - jay shilstone - continued from page 12 14 When I asked him about his aggregates he said he was using a single size 25mm rock and a single fine concrete sand. He assumed that as long as his aggregates complied with EN-12620 that he could make good concrete from them. He didn’t know the rest of the story. MOST EUROPEAN CONCRETE USE MULTIPLE AGGREGATE As I am certain many of the readers know, most European concrete mixtures use multiple aggregate and not just one rock and one sand. In this manner an appropriate combined aggregate grading can be constructed. By just using a single coarse rock and a fine sand the paving contractor created a gap-graded aggregate mix that was certain to segregate. This was the basis for much of his problem. People in the concrete industry have stories that are worth listening to, also. Bryant Mather, and his wife Kay, were fascinating people. Not only was Bryant a widely respected concrete technologist who worked for the U.S. Army Corps of Engineers, but he was also a well-known lepidopterist (a butterfly collector). DISCOVERED AND NAMED 4 DIFFERENT SPECIES Bryant discovered and named 4 different species of butterflies and, on his death, willed his immense butterfly collection to the Smithsonian Institution. I know that butterflies aren’t of interest to everyone in our industry, but Bryant also knew concrete backwards and forwards as well. You could mention just about any topic related to concrete and he would boom out in his stentorian voice and say, “I remember back in 1957 we ran into that…” UNDERSTAND LONG AND VARIED STORY If you really wanted to understand Bryant and his knowledge of concrete, you needed to know something of his long and varied history. I don’t expect that “The History of Concrete” will become the next Peter Jackson/ Mel Gibson action flick, although you never know. (There is a comic book called Concrete, about a man made of living concrete, which might someday make it to the big screen.) I think that concrete has a story and we in the industry have a responsibility to make certain that we pass that story on to others and don’t just educate future generations with factoids and data bites. In addition, as we learn about concrete we need to make certain we not only learn the facts and figures about a research study, but also understand the background story to make certain we have a framework on which to hang our learning. Our knowledge of concrete is like concrete itself. All the facts and bits of data are like the coarse aggregate, taking up the majority of space in our knowledge of concrete. It is the story of the concrete that makes up the mortar that holds these facts together. Until next time, Jay Shilstone


The Concrete Times Summer 2015
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