Effect of drying on cement-based materials pore structure as identified by mercury intrusion porosimetry -: A comparative study between oven-, vacuum-, and freeze-drying

Diffusive and convective transport properties are essential for cement-based materials durability studies. To understand and model such transport mechanisms, information on physical intrinsic parameters such as porosity and pore structure is needed. Mercury intrusion porosimetry (MIP) has been used for a long time as a convenient means for porous space investigation. This method requires complete material water removal, generally achieved through various drying procedures. In this context, the effects of four drying methods (oven-drying at 60 degreesC and 105 degreesC, vacuum-drying, and freeze-drying-sublimation) on porosity and pore structure determined by MIP, were compared. Experimental measurements were performed on CEM I (OPC) and CEM V (blastfurnace slag-pulverised fuel ash, BFS-PFA) pure cement pastes and concretes. Results confirmed that oven-drying generates important damages for the materials microstructure in the capillary porosity domain and confirmed the applicability of the freeze-drying technique as a suitable drying procedure to investigate cement-based materials pore structure using MIR. (C) 2001 Elsevier Science Ltd. All fights reserved.