改性木质素磺酸盐减水剂的性能研究

Investigation on Performance of Modified Lignosulphonate Based Plasticizer

阐述了国内木质素磺酸盐减水剂（LS）的生产应用现状，认为它虽属环保型产品，但在技术方面存在局限性．通过化学方法对LS改性，得到了一种接有羧基基团的改性木质素磺酸盐减水剂（MLS）．对其性能进行的研究结果表明：与LS相比，MLS的减水率有较大幅度提高，当MLS掺量为0．25％～0．40％（占水泥质量的百分数）时，混凝土减水率可达14．5％～19．6％，接近萘系高效减水剂（NSF）的减水效果；掺加MLS的混凝土28d抗压强度比与掺加NSF者相当；用MLS替代部分NSF可有效改善混凝土坍落度保持性．另外还探讨了正确评价MLS塑化效果的方法，认为采用混凝土减水率指标更能真实反映其应用效果．

The status of production and application of domestic lignosulphonate based plasticizer （LS） is discussed. It is recognized that LS still has limitation in application technique though LS is regarded as a kind of eco-product. By chemical treatment of LS, a kind of modified lignosulphonate based plasticizer（MLS） was obtained. The modification was confirmed to be connected with carboxyl groups through infra-red spectroscopy analysis. The properties of MLS was tested and the results indicate that with the dosage of 0.25%-0.40%（by mass of cement） the water reducing rate of MLS can reach 14.5%-19.6%, much greater than that of LS, and even as high as that of naphthalene sulphate based superplasticizer（NSF）. The compressive strength ratio of concrete added with MLS is approximately the same as that of concrete added with NSF; the slump retention of concrete is improved significantly when NSF is partially replaced by MLS. It is rec- ommended that the plasticizing efficiency of MLS should be more accurately judged by water reducing rate instead of fluidity of paste.