February Technical Meeting

  • 19 Feb 2014
  • 11:30 AM - 1:00 PM
  • Hotel VQ
  • 54

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February 19th Luncheon - Lunch Sponsored by Holcim Cement

 

 

               

 

Bret Robertson will be our guest speaker for our February 19th luncheon, in which Bret will be discussing a new method of tensile testing for concrete. 

 

Concrete Tension, Pulling Apart the Industry Standard

 

Bret Robertson grew up in Oklahoma. He earned a B.S. in Civil Engineering in 2008 and a M.S. in Structural Engineering/Mechanics in 2010, at Oklahoma State University. His graduate studies included cement chemistry and an accelerated test method for delayed Ettringite formation.

Bret has been a Civil Engineer for the Materials Engineering and Research Laboratory since 2010. He currently has multiple research projects ongoing, including a multi-year tension size effects study that is utilizing 8” NMSA mixes. Other research includes, repair material compatibility with the Navy, leaching of lithium soaked lightweight aggregate in water flow structures, a new approach to ASR with TTI Texas A&M, and recycled sludge waste as binders.

 

Concrete tension testing is essential for many structures. But what test should be performed? The cheapest and easiest test is the split tension test. This test gives us a value but the true meaning of that value is unknown.  Some researchers have published that splitting tension can hardly be assumed to be a material property. A little known fact about the split tension test is that by changing the diameter of the cylinders the strengths follow a linear strength distribution. In general, 4” or 6” diameter cylinders test at 8-14% of the compressive strength of concrete. Should we depend on a test that happens to fall in our comfort zone value for tension? This discussion will go through the history and future of tension testing.

 

 

 

 

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