Effect of Polycarboxylicacid Plasticizer on Characteristics of α-Calcium Sulfate Hemihydrate

Purpose: studied the mechanism of polycarboxylicacid plasticizing effect on α-calcium sulfate hemihydrate. Methods: the adsorbed amount was tested by ultraviolet visible absorption spectrum method, ζ potential was measured by micro-electrophoresis analysis, and the corresponding workability was studied. Results: firstly, polycarboxylicacid plasticizer was adsorbed on α-calcium sulfate hemihydrate by Van Der Waals force and the saturated adsorption quantity of polycarboxylicacid plasticizer (HC) was about 5.8mg/g; secondly, the decisive factor for polycarboxylicacid plasticizer to disperse α-calcium sulfate hemihydrate particles was the steric hindrance of polycarboxylicacid plasticizer, and the maximum ζ potential of α-calcium sulfate hemihydrate with polycarboxylicacid plasticizer was-9.360mv, much less than β-calcium sulfate hemihydrate under the same conditions; finally, the perfect mixing content of polycarboxylicacid plasticizer was 0.3%~0.6%; it increased fluidity by 66%, to the maximum 300mm.