The effects of nanoscale expansive agents on the mechanical properties of non-shrink cement-based composites: The influence of nano-MgO addition

The mechanical properties and permeability of cement-based composites containing nano-MgO were studied and the experimental results indicated that the mechanical strength of the composites mixed with the nano-MgO, measured at different ages, were higher than those of a plain composite. The results from the treated composites compared to those of the plain composite indicated that the compressive strength of sample containing 1% nano-MgO of binder by weight (MGC1) increased by 103% and 80% at 7 days and 28 days, respectively, and that the flexural strength of MGC1 equaled 4.66 and 5.1 MPa, which were 95% and 70% higher than those of the plain composite (PC), respectively. SEM revealed that the microstructure of the composites with nano-MgO were more compact and homogeneous than that of plain composite because of expansive effect of nano-MgO. This paper describes the mechanism of the nano-MgO effects on composites’ nanostructure.