Influences of Modified Naphthalene Sulphonate Superplasticizer on the Performances of Cementitious Materials

Through the complex formulation and modification between the naphthalene sulphonate superplasticizer and oxidative etherified starch(OES) prepared by the oxidation and etherification treatment,the effects of the modified naphthalene sulphonate superplasticizer on the performances of cementitious materials are studied.The results indicate that the modified naphthalene sulphonate superplasticizer can obviously improve the slump retaining of naphthalene sulphonate superplasticizer,the flowability of cement paste is effectively improved compared to ordinary naphthalene sulphonate superplasticizer and the hydration induction period can be prolonged obviously.The slump loss of cement paste with 13% modified naphthalene sulphonate superplasticizer is only 6% after 2 hours which is much lower than that of the ordinary naphthalene sulphonate superplasticizer.In comparison with cement paste added with naphthalene sulphonate superplasticizer,when the content of OES is 5%～13%,the flowability loss of cement paste after 2 hours reduces by 17%～89%,and 28d compressive strength is raised by 12%～20%.