Research On Synthesis And Their Performances Of Superplasticizers Of Polycarboxylate Series

Polycarboxylic type superplasticizer is a new high performance superplasticizer with very high water reducing rate at low dosage.It is of the characteristics of low slump loss,little effect on setting time and clearly effect on strength rise.Polycarboxylic type superplasticizer has been research hotpot of concrete superplasticizer in 21th century.This thesis included the following main points:1.The macromonomers synthesis of polycarboxylic superplasticizer were studied.. Choosed crylic acid,mateic anhydride,allyl chloride and polyethylene glycol as main materials,and synthesized PA,PMA and PO.The diversified factors which affected synthesis reaction were studied,and experiment condition of macromonomer synthesis was confirmed.2.Polycarboxylic superplasticizers were synthesized by self-regulating macromonomers,and confirmed experiment condition of polymerization reaction,and the optimal raw materials mixture ratio of polycarboxylic have been determined with the help oforthogonal test means:(1)The optimal raw materials mixture ratio of PC-1:n(SAS):n(AA(MA)): n(PAl500)=3.0:4.0:1.25.When water-cement ratio of W/C=0.29,W=0.4%,the original fluidity of cement grout reached 220mm,and fluidity of cement grout reached 180mm after sixty minutes.The 28d compressive strength ratio of concrete adding PC-1 was 126%when W=0.3%.(2)The optimal raw materials mixture ratio of PC-2:n(SAS):n(AA(MA)): n(PMA800)=3.0:3.0:1.0.The original fluidity of cement grout reached 235mm,and fluidity of cement grout reached 204mm after sixty minutes when water-cement ratio of W/C=0.29,W=0.4%.(3)The optimal raw materials mixture ratio of PC-3:n(SAS):n(AA(MA)): n(PO1500)=1.0:4.0:1.0.When water-cement ratio of W/C=0.29,W=0.4%,the original fluidity of cement grout reached 265mm,and fluidity of cement grout reached 236mm after sixty minutes.The water-reducing ratio was 20.7%and 28d compressive strength ratio of concrete adding PC-3 was 151%when W=0.3%.3.The effect of different macromonomers and different length of side chain to capabilities of superplasticizers,and surface properties such as limiting viscosity, surface tension,Zeta potential,dispersity of cement-water system adding superplasticizers were studied,and structural characterization by IR.The investigation showed that weakening gradation which connected with effect of different macromonomers to capabilities of superplasticizers was PO,PMA,PA.The excellent dispersibility of superplasticizers appeared when length of side chain of PA was 35,length of side chain of PMA was 18,length of side chain of PO was 35.Preferably dispersity appeared when limiting viscosity of PC-1 between 0.135～0.145dL·g^-1,limiting viscosity of PC-2 between 0.12～0.13dL·g^-1,limiting viscosity of PC-3 between 0.13～0.14 dL·g^-1.The respectively average partical size of cement-water system which adding PO,PMA,PA was 0.08μm,0.16μm,0.24μm when W=0.4%.