Nanoengineering of Macroscale Materials
Speaker: Claire E. White, Los Alamos National Laboratory
Series: CEE Departmental Seminars
Location: Friend Center 004
Date/Time: Thursday, December 20, 2012, 3:30 p.m. - 5:00 p.m.
With the ever-increasing demand to use clean and environmentally beneficial materials in our technologically progressing industries, the need for advanced molecular-based understanding of these materials together with a clear understanding of their life cycles is becoming more and more important. Geopolymer concrete, produced by alkali-activation of industrially-generated aluminosilicate precursors including coal-derived fly ash and ground granulated blast furnace slag, possesses similar macroscopic mechanical properties to traditional ordinary Portland cement-based (OPC) concrete, at a much reduced CO2 emission cost. The success of this material in the industrial setting is in large part due to the increasing pressure to use environmentally friendly materials, and with Portland cement accounting for 5-8% of global man-made CO2 emissions, geopolymer concrete is a viable alternative.
It has been shown that there is a direct correlation between the nature of the molecular structure of an engineering material, its formation, and changes over time, with macroscopic properties such as strength and durability. However, the majority of research carried out to measure and understand these material properties is limited to these larger length scales, which fails to capture the true nanoscale mechanisms at play. In this presentation I will address (i) the pressing need to understand and control the early age performance of low-CO2 geopolymer binders and concretes, and (ii) the anticipated role of different carbonate phases in CO2 sequestration and carbonation of alkali-activated cements, using advanced nanoscale simulation methods (including quantum chemistry and coarse-grained models) and state-of-the-art beamline experimental techniques (pair distribution function analysis, small-angle scattering and X-ray tomography). The results directly impact the concrete and CO2 sequestration industries, and greatly help the implementation of low-CO2 construction materials in the industrial sector.