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Effects of calcium on the geopolymer reaction



Event Date 06 Aug 2014 (Wed), 10:00 AM - 11:30 AM
Venue CBE-SR2, Block N1.2, Level B3 , School of Chemical and Biomedical Engineering, NTU (Location Map)
Organiser NTU-JTC Industrial Infrastructure Innovation Centre (Email : d-ntujtci3c@ntu.edu.sg  Tel/Fax : 65927956)


Event Info

Seminar on
Effects of calcium on the geopolymer reaction

Seminar Topic:
The geopolymer system is being widely studied for many ceramic applications, not the least of which is the binder in structural concrete. Geopolymers form by reaction of a powdered aluminosilicate precursor with an aqueous alkali hydroxide solution. The precursor most widely studied is metakaolin, whose reaction occasionally forms a crystalline zeolite but in our experiments always forms an amorphous gel, and we are probing its molecular structure mainly using nuclear magnetic resonance (MAS-NMR). Calcium is often present in the reaction and is seen to speed up setting and increase strength of the geopolymer. When calcium is present, calcium silicate hydrate is presumed to form in addition to the geopolymer gel, although no direct experimental evidence for this phase is found in the literature. Identifying calcium silicate hydrate in the presence of geopolymer gel is rather difficult, but we have successfully identified both phases using MAS-NMR. Evidence for this identification will be presented and discussed during this seminar.

About the Speaker:
Professor Leslie J. Struble, Director of the Center for Cement Composite Materials at University of Illinois at Urbana-Champaign (UIUC) and Associate Editor of the Journal of the American Ceramic Society (JACerS), holds a B.A. in Chemistry (Pitzer College), an M.S. in Civil Engineering (Purdue University, 1979), and a Ph.D. in Civil Engineering (Purdue University, 1987). She is a member and fellow of the American Society for Testing and Materials (ASTM), and a member of the American Association of University Professors. Professor Struble has extensive experience in concrete science and technology as well as composition, microstructure, and performance of building materials. Currently, she is directing research on geopolymer set and on molecular structure and creep of calcium silicate hydrate. She has edited several books and proceedings and has authored or co-authored more than 140 publications dealing with various aspects of cement and concrete.

 

Please note that seminar's date has been changed to 6th August, 2014 (Wed)



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