My name is Emily Stinson and I am a junior in the Civil and Environmental Engineering department. Within the Civil and Environmental Engineering department, I am following the structural engineering track. In addition, I am also pursuing a certificate in Sustainable Energy through the Mechanical and Aerospace Engineering department. For my independent work, I'm am investigating optimized aggregate packings. It is possible to create very dense binary packings, packings of spheres of two sizes, by choosing the size ratio and proportions correctly. Recent numerical simulations claim to have discovered size ratios and proportions that allow for denser binary packings that have previously been overlooked. I am investigating whether we can validate this new theory experimentally. Even though binary aggregate is not practical, the mathematical approach would permit optimization of broader size distributions. If validated, it may be possible to reduce the amount of cement in concrete which has large implications since production of cement is very expensive and contributes 5% of the anthropogenic CO2 emissions.
This is an example of a packing of particles with a 10/1 diameter ratio. The volume fraction of spheres is higher than the aggregate content typically used in concrete.