(5) Coupled heat and mass transfer leading to pore pressure prediction in HSC with and without
polypropylene fibers, and investigation of the need for new numerical methods to handle the saturatedunsaturated
interface zone. High temperature exposures cause vaporization of pore water in concrete. The
slow transport of water and water vapor then leads to elevated pore pressure levels. Since the elevated pore
pressures may be a cause of damage in the concrete, accurate predictions of these pressures need to be
developed. Because a sharp interface develops between the saturated and unsaturated parts of the concrete
(liquid:vapor interface), it is possible that existing analytical and numerical tools may be inadequate.
Therefore the development of new mathematical tools needs to be investigated. The role of polypropylene
fibers, in terms of the mechanism by which they can give fire protection, needs to be understood.
(7) Coupling of pore pressure and fracture consideration. The elevated pore pressures must be quantitatively
linked to spalling (fracture) of the concrete. Since it has been known for a long time that the fracture of
concrete at room temperature is not controlled by a simple strength criterion, but is rather a fracture process,
it is reasonable to assume that a similar situation applies at fire temperatures as well.