Study on synthesis and properties of a phosphating clay resistance agent for concrete
In view of the negative impact of high clay content of sand on concrete doped with polycarboxylic acid superplasti-cizer,a new clay resistant agent KN-P was synthesized using maleic anhydride(MA)and phosphate(PPs)as monomers and ammo-nium persulfate(APS)as initiator,which can inhibit the side effects of soil in fine aggregates of concrete.The best conditions of synthesizing:n(MA)∶n(PPs)=2.5∶1,the dosage of catalyst and APS were 0.08%and 8%of MA mass respectively,the APS drip time was 3.5 h at 70℃,and the temperature was kept at 80℃ for 2 h.The result of FTIR analysis showed that the synthesized product was phosphorous polycarboxylic acid copolymer.The cement paste fluidity test shows that the initial and 1 h cement paste fluidity was 292 mm and 295 mm respectively,when the cement adding 10%soil,the content of polycarboxylic acid superplasticizer was only 0.10%and the content of KN-P was 0.08%,and the slump,expansion of concrete was 190 mm and 420 mm respectively after 1 h.The results showed that KN-P could inhibit the negative effects of fine aggregates with high clay content.