The explosive spalling of heated concrete is a complex process that is not yet completely understood. The spalling may be caused by increasing vapor pressures in the pores of the concrete. The experiments discussed in this report are the first to combine temperature and pressure measurements with 1D-moisture profiles, during the heating of concrete. For this, cylindrical concrete (W/C=0.54) samples with a diameter of 75 mm and a length of 100 mm are heated at one flat face. Pressures are measured with a CSTB-type pressure gauge, located at the central axis of the cylinder, at a depth of 20-40 mm from the heated face. Maximum pressures ranged from 0.27 MPa to 0.85 MPa. The spatial moisture distribution is obtained by placing the sample in an NMR scanner during heating. Temperatures are measured with thermocouples in the pressure gauge and at several depths at the side of the samples. The combination of temperature, pressure and moisture measurements shows that the highest pressures are reached when the drying front passes. Furthermore, near the drying front the pressure follows the saturated vapor pressure. The results of the combined measurements of moisture, pressure and temperature are promising for future verifications of numerical simulations.
|Date of Award||31 Aug 2013|
|Supervisor||Leo Pel (Supervisor 1)|