活化磺化麦草碱木质素高效减水剂性能的研究

Study on performance of activation sulfonation straw alkali lignin superplasticizer GSAL

以麦草碱木质素为原料,通过活化、磺化、缩合制备高效减水剂GSAL,研究其对水泥和混凝土性能的影响,并探讨了GSAL的减水作用机理。结果表明,水灰比为0.32,掺0.6%GSAL的水泥净浆流动度为248 mm,比掺奈系减水剂FDN的水泥净浆流动度大30 mm,水泥净浆流动度120 min后仅损失17.3%,水泥净浆的终凝时间延长2～3 h,混凝土减水率达24.5%,比FDN高3.7%,GSAL使混凝土3 d、28 d抗压强度比分别达到178%和154%,比掺FDN分别提高36%和33%。通过表面物化性能研究表明,GSAL对水泥的减水分散作用主要是由于其对水泥颗粒具有良好的润湿作用、适当的气泡润滑作用以及在水泥颗粒表面形成了较强的静电斥力。

Superplasticizer GSAL was prepared by activation, sulfonation and condensation reaction using straw alkali lignin as raw material. Effect of superplasticizer GSAL on performance of cement and concrete were studied and water-reducing mechanism of GSAL was also investigated.The results showed that at water to cement ratio of 0.32, the fluidity of cement paste with 0.6% GSAL was 248 nun that was 30 mm more than that of FDN; the relative fluidity loss of cement paste with GSAL amount to only 17.3% after 2h;the final setting time of GSAL was about 2-3 h retarded; the water reducing ratio of concrete with 0.6% GSAL was 24.5% that was about 3.7% more than that of FDN, compression strength ratios of concrete at 3 d, 28 d were up to 178% and 154% respectively that was about 36% and 33% higher than that of FDN respectively.Research findings of physical-chemical performance revealed that water reducing mechanism of GSAL owes to the excellent wetting,lubricating for cement particle and strong electrostatic repulsion on cement particle surface.