  Permeability and heat transport through building materials ultimately
dictates their insulatory performance over a buildings service lifetime.
Experiments combining XCT with numerical modelling are an accepted method of
studying pore scale processes and have been used extensively in the oil and gas
industry to study highly complex reservoir rocks. However, despite the obvious
similarities in structure and application, these techniques have not yet been
widely adopted by the building and construction industry. An experimental
investigation was performed on the pore structure of several building
materials, including conventional, historic, and innovative, using XCT and
direct numerical simulation. Six samples were imaged at between a 4 and 15
micron resolution inside a micro-CT scanner. The porosity and connectivity were
extracted with the grain, throat, and pore size distributions using image
analysis. The permeability, velocity, and thermal conductivity were then
investigated using GeoChemFoam, our highly-versatile and open source numerical
solver. It was found that each material had a unique, heterogeneous and
sometimes multi-scale structure that had a large impact on the permeability and
thermal conductivity. Furthermore, it was found that the method of including
sub-resolution porosity directly effected these bulk property calculations for
both parameters, especially in the materials with high structural
heterogeneity. This is the first multi-scale study of structure, flow and heat
transport on building materials and this workflow could easily be adapted to
understand and improve designs in other industries that use porous materials
such as fuel cells and batteries technology, lightweight materials and
insulation, and semiconductors.
