木质素磺酸钠与聚羧酸减水剂复配研究

通过氧化、磺甲基化改性造纸黑液制取木质素磺酸钠(SLS),磺化度为1.023 7 mmol/L,重均相对分子质量(M_w)为26 320;将SLS与聚羧酸高效减水剂(PCE)按一定比例复配制备复合减水剂,SLS质量分数为10%、20%、30%和40%时,分别制得复合减水剂BPCE1~BPCE4。复合减水剂对水泥颗粒表面吸附层厚度和水泥浆Zeta电位分析表明:吸附层厚度随SLS质量分数增加而增加,水泥浆Zeta电位在SLS质量分数为20%时显示出绝对值最大。采用复配木质素磺酸钠的复合聚羧酸减水剂制备混凝土,复合减水剂掺量0.18%、SLS总掺量1%。通过净浆流动度、胶砂流动度、泌水率、减水率、混凝土抗压强度等指标对复合减水剂进行综合性能分析。结果表明:含20%SLS的复合聚羧酸减水剂BPCE2减水剂综合性能最佳。

Sodium Ligninsulfonate and Its Blendings with Polycarboxylic Superplasticizer

Sodium lignosulfonate ( SLS ) was obtained by oxidation and sulfomethylation from pulp black liquor, and the sulfonation degree and weight-average molecular weight ( Mw ) were 1. 023 7 mmol/L and 26 320, respectively. A series of complex superplasticizers ( BPCE1, BPCE2, BPCE3 and BPCE4 ) were prepared by blending SLS and polycarboxylate superplasticizer ( PCE) with various ratio. The adsorption layer thickness on cement particle surface and slurry Zeta potential of complex superplasticizer were studied. The results showed that the thickness increased with the SLS content increase. The Zeta potential of slurry showed the greatest absolute value when the mass fraction of SLS was 20%. The cement and concrete was prepared with the complex superplasticizer dosage 0. 18 % and SLS 1 % of the total dosage. The research results of paste fluidity, mortar fluidity, bleeding rate, the water reducing ratio and compressive strength of concrete showed that the optimal performance was realized as the 20 % SLS was used in the complex superplasticizer BPCE2.