Constituent phases and mechanical properties of iron oxide-additioned phosphoaluminate cement

Iron oxide was added to phosphoaluminate clinker and its effects on cement constituents were determined using XRD, DSC, SEM-EDS and conduction calorimetry analysis. The variations in compressive strength were also studied. The results showed that in moderate amounts, iron oxide acts as a mineraliser during clinker sintering, furthering the conversion of CA(1-Y)(P-Y) to LHss at a lower temperature than normally required for that reaction. The main constituents of iron oxide-rich phosphoaluminate clinker included LHss, CA(1-Y)(P-Y), CP1-Z(A(Z)) and ferrite. The EDS findings showed that the composition of the ferrite phase was nonuniform. The conclusion drawn was that by modifying the dose of Fe2O3, the composition of phosphoaluminate cement can be controlled to produce clinker and cement compliant with different mechanical strength requirements. The conduction calorimetry findings were consistent with those results.