Study on effect of ash calcium on properties of phosphorus building gypsum doped with PCE
In order to further promote the application of phosphorus building gypsum,with ash calcium as the alkaline regu-lator,a comparative study was conducted on the effects of ash calcium content on the working performance,mechanical properties,phase composition,and micro-morphology of phosphorus building gypsum with or without polycarboxylate super-plasticizer(PCE).The results showed that,without PCE,as the ash calcium content increased,the pH of the phosphorus building gypsum was gradually increased,the water-soluble P2O5 content was gradually decreased,the fluidity was de-creased by more than 59.5%,the standard consistency water consumption was increased,and the strength was firstly de-creased and then increased,but the strength was still lower than the original phosphorus building gypsum.The flexural and compressive strengths were reduced by 63.3%and 54.4%,respectively,compared to those without ash calcium.When PCE was added,the incorporation of ash calcium could increase the adsorption capacity of phosphorus building gypsum for PCE by more than 10 times,thus improving the adverse effects of ash calcium incorporation on the fluidity,standard consistency water consumption,and strength of phosphorus building gypsum.The strength was firstly increased,then decreased,and then increased again as the ash calcium content increased.The flexural and compressive strengths were increased by 11.1%and 48.9%,respectively,compared to those without ash calcium.The results of XRD and SEM analysis showed that ash cal-cium was mainly reacted with H3PO4 and H2PO4-in phosphorus building gypsum to form insoluble and amorphous small par-ticles,reducing the mutual overlap degree between dihydrate gypsum crystals,resulting in a decrease in strength.In the pro-duction and processing of phosphorus building gypsum,the ash calcium content should be greater than 1.3%,and should be used with PCE.
phosphorus building gypsumash calciumpolycarboxylate superplasticizerstrengthmicrostructure
万方数据
维普
