Slides

So my name is Benn Stutrud, and I am Sister Mary Concrete. I am the one giving this presentation at ACI. I have finished my slides and thought it would be interesting to post and talk about them…

In St. Paul, Minnesota the Lafayette Bridge is being constructed with mass concrete elements. To give you an idea for what this entails consider the following definitions:

Precautions have to be taken while curing these mass elements due to potential thermal cracking and delayed Ettringite Formation (DEF).

The remedies for this are optimizing the mix design for lower heat generation, and using thermal insulation during the curing process.

Sister Mary Concrete’s strategy was to first create a mix design with high Pozzolans content, and large aggregate yield. This effectively lowers the heat of hydration. The following shows the information for our footing mix:

 Being that I had a math background, I had to go in depth into the heat equation. So, I showed the variables, Numerical analysis, and figure as follows:

Before we could create any modeling, there was a number of thermal tests that we had to conduct. The slides on this are fairly self-explanatory…   

I then go through a number of results obtained for a footing and pier:

For the conclusion, I really want to talk about the importance of Pozzolans in the mix design for mass concrete. Also, I made some rough calculations for thermal cracking as a conversation piece for future considerations with high pozzolan mixes.

Well that’s my slideshow. Feel free to post comments/questions.