Elements enrichment characteristics in interfacial transition zone of MgO concrete

Microscopic techniques were employed to investigate element enrichment characteristics in the vicinity of the interfacial transition zone (ITZ) of MgO concrete. Results indicated that the morphology of products of hydration in ITZ was similar to the cement matrix but different by amount, size and crystal features. Elements Ca, Si, Al and Mg were obviously enriched in ITZ and uniformity of their distribution grew with age. MgO was non-uniformly distributed in concrete, accounting for 8.47% and 4.53% respectively in paste and ITZ area despite of fully mixture in construction, yet MgO showed inclination of migrating towards ITZ area with in-depth hydration and the gap in between was mitigated from 3.94% at 7 d to 1.31% at 240 d so far as 5% of light-burnt MgO was incorporated.