Effects of hydration mechanism on mechanical properties of diatomite-cement composites

In this study, the relationships among compressive strengths with hydration mechanisms, microstructure characterizations and physical properties of diatomite-substituted cement pastes and mortars were researched. In order to determine the properties of cement pastes and mortars, X–ray diffraction, fourier transforms infrared spectroscopy, thermal analysis, scanning electron microscopy and energy dispersive X-ray spectroscopy techniques and standard cement tests were utilized at 2, 7, 28 and 90 days. The results revealed that portlandite content decreased gradually as a consequence of increasing age and addition of diatomite, and diatomite-substituted cements have high degree of hydration. Furthermore, the diatomite substituted cements had more compact structure by creating more hydration products at 28 and 90 days. This compact structure also positively contributed to the compressive strength of cement mortars at later ages.