Pore size distribution of metakaolin paste

The porosity and pore size distribution of cured OPC-metakaolin paste has been investigated. Pastes containing 0,5,10 and 15% metakaolin were prepared at a constant water/binder (w/b) ratio of 0.55. Specimens were moist cured for periods from 3 to 365 days. The intruded pore volume and the pore structure were determined by mercury intrusion porosimetry. The proportion of large pores (radius > 0.02 mm) in the paste decreases with both increase in metakaolin content and increase in curing time. Although the total intruded pore volume generally decreases with increase in curing time it is found to increase with increase in metakaolin content. Also an increase in pore volume is observed between the curing times of 14 and 28 days for pastes containing metakaolin. This latter observation is explained in terms of two possible mechanisms. Copyright (C) 1996 Elsevier Science Ltd