Enhancement of Mechanical Properties,Wettability, Roughness, and Thermal Insulation of Epoxy–Cement Composites for Building Construction

In this study, epoxy–cement composites with different concentrations of cement
nanofiller and ~67.5 nm in size (0, 5, 10, 15, and 20 wt%) were synthesized using the
solution casting method. The epoxy–cement composites’ structural, mechanical, wettability,
roughness, and thermal insulation were investigated. The synthesized epoxy resin is
amorphous, whereas epoxy–cement composites are crystalline, and its crystallinity depends
on the filler ratio. The incorporated cement hindered the spread of cracks and voids in the
composite with few illuminated regions, and the epoxy/cement interface was identified.
The Shore D hardness, impact strength, and flexural strength gradually increased to 92.3,
6.1 kJ/m2, and 40.6 MPa, respectively, with an increase in the cement ratio up to 20 wt%. In
contrast, the incorporation of a cement ratio of up to 20 wt% reduced thermal conductivity
from 0.22 to 0.16 W/m·K. These findings indicated that resin and cement nanoparticle fillers
affected the chemical composition of epoxy, which resulted in high molecular compaction
and thus strong mechanical resistance and enhanced thermal insulation. The roughness
and water contact angle (WCA) of epoxy increased by increasing the cement nanofiller. In
contrast, the surface energy (γ) of a solid surface decreased, indicating an inverse relation
compared to the behavior of roughness and WCA. The reduction in γ and the creation of
a rough surface with higher WCA can produce a suitable hydrophobic surface of lower
wettability on the epoxy surface. Accordingly, the developed epoxy–cement composites
benefit building construction requirements, among other engineering applications