Semester:Week 1Chem sem 1At this week's seminar, Leslie Struble, from the Department of Civil and Environmental Engineering from the Universty of Illinois, came and spoke about the chemistry of concrete. This was my first experience learning about concrete, and though it was not in my particular field of interest, I learned quite a bit from her presentation. She told us that Portland cement was a critical constituent in concrete. The portland cement contains C3S that reacts with water. She spoke about CSH, which forms during that reaction, the substance that fills in the pores and holds the rocks and sand together. The details of its nanostructure were yet to be understood until as of recent. It turns out that the calcium has an octahedral geometry and the Silica has a tetrahedral geometry. She explained that the CSH chain grows by adding bridging tetrahedra.When discussing her research, she mentioned that they were looking at the effects of composition on the nanostructure in terms of cross-linking and chain length. They explores the idea of whether longer chains could mean increased elastic modulus and whether increased cross-linking can reduce creep. She's working on looking into synthesizing C-(A)-S-H which could prevent carbonation and using NMR to measure the cross-linking and the chain length. Struble had extensive knowledge on her research and she did a good job delivering her presentation.
