Study of adsorptive behaviours of polynaphthalene sulfonate superplasticiser on 3CaO·3Al₂O₃·CaSO₄ mineral

Calcium sulfoaluminate (3CaO·3Al₂O₃·CaSO₄, C₄A₃S¯) was synthesised with pure chemical reagents. The adsorption amounts of polynaphthalene sulfonate superplasticiser (NSF) on the surface of C₄A₃S¯ mineral and the mineral mixture (C₄A₃S¯+Ca(OH)₂+CaSO₄·2H₂O) were detected by ultraviolet–visible absorption spectrometry. The adsorptive behaviours of NSF on the surface of mineral particles in the hydration system were studied. The results showed that the adsorption amount of NSF on C₄A₃S¯ mineral and the mineral mixture increased with higher initial concentration, the adsorption amount and the maximum adsorption amount increased with prolonged hydration time, and the adsorption amount and maximum adsorption amount of NSF on the mineral mixture were more than those on C₄A₃S¯ mineral in the hydration system within the same hydration time.