As a composite material, concrete’s performance can be expected to depend on the properties of the interfaces between its two major components, aggregate and cement paste. The general consensus is that the interfacial zone is a region, up to 50 µm wide around each aggregate, containing more porosity and larger pores than the bulk cement paste, and often containing large calcium hydroxide crystals. Due to these features, the interfacial zone is often considered to be the weak link in concrete with respect to mechanical performance and durability.
In this exercise, a digital-based cement microstructural model is applied to simulate interfacial zone microstructural development. Reasons for the differences between interfacial zone and bulk paste microstructure and methods for improving the structure of this weak link will be explored.