Interfacial Transition Zone Meso-Structure of MgO Concrete Loaded to Failure by Computed Tomography

Abstract

The computed tomography was introduced to track the development of cracks in cement matrix and interfacial transition zone of MgO concrete under load to failure. Results indicated that some pores were present before concrete was loaded due to none compaction which would tend to initiate cracks expanding. After loading, energy transferring route kept changing and extended towards weak area and it chose to be released through aggregates when concentrated stress on cracks tip surpassed ultimate load with consequences of some cracks getting interconnected with each other through cement matrix. Differentiated and Binarized CT images analysis confirmed that width of cracks was increased and extending routes diversified with loading implemented and interfacial transition zone remained primary choice for cracks development.

Hydration of Reactive MgO as Partial Cement Replacement and Its Influence on the Macroperformance of Cementitious Mortars

“…ere have been quite a few studies on the microstructure of cementitious composites containing reactive MgO, by means of X-ray diffraction (XRD) and thermogravimetric analyses [11,23,[31][32][33][34][35][36], specifically on the formation of Mg(OH) 2 and M-S-H phases [16,37]. Various reports based on SEM analyses have suggested that the hydration products of MgO exhibit a tendency to migrate towards the interfacial transition zone (ITZ) area thereby reducing the porosity of the resulting material [38][39][40][41].…”