Study On Synthesis And Properties Of Polycarboxylate Superlasticezer For Magnesium Oxychloride Cement

The workability of concrete has great influence on mixing,transportation and paving of congcrete.Only good workability can smoothy concrete construction be ensured,which can bring with good performance of concrete using,effectively avoid cracks,subsidence and other pavement disease.However,there is little research on the workability of magnesium oxychloride cement(MOC),and the water reducing rate of commercial water-reducing agent in MOC is only about 10%,even as low as 5.5%.In view of this,this paper firstly used three kinds of rheological models to fit the rheological curves of the based MOC slurry obtained by the test,selecting the most suitable rheological model for MOC.Secondly,this paper designed and synthesized a series of polycarboxylate superplasticizer,whose synthesis conditions were determined by the test of the fluidity and flow rate of magnesium chloride cement.Thirdly,the application effect of synthetic water reducing agent in magnesium oxychloride cement was evaluated.The main conclusions are as follows:(1)the most effective model is power-law rheological model,and adding water reducing agent is the most suitable method to improve the fluidity of the MOC.(2)the synthetic water reducing agent reaches its best performance when the molar ratio of n(ether A):n(ether C):n(acid):n(chain transfer agent)is 3:1:24:4 under the T3 temperature,and the dosage of initiator is 2% of the hole monomer.(3)using 0.25% HN-C and 0.6% synthetic water reducing agent at the same time can effectively solve the problem of large loss of time and improve the strength and water resistance of MOC.(4)the incorporation of water-reducing agent optimizes the structure of the MOC,increasing the content of 5.1.8 crystals,in which the content of 5.1.8 is higher than that of single mixed with water-reducing agent.