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玉米秸秆糖醇黑液在100~140℃下与甲醛、Na_2SO_3溶液(摩尔比0.6~0.8)发生磺化、磺甲基化反应2~4h,制备出木质素基减水剂,由傅里叶变换红外光谱表征其结构。通过减水率、凝结时间及抗压强度分析木质素基减水剂对水泥水化的作用规律,并结合X射线衍射和扫描电镜研究木质素基减水剂对水泥水化进程的影响。结果表明:改性制备的木质素基减水剂,可有效减缓水泥初期水化,促进后期水化,对水泥颗粒有良好的分散效果;水灰比0.35、掺量为1.2%时,减水率为17.5%,达到高效减水剂标准;掺加减水剂试样的初凝、终凝时间均显著延长,能有效提高水泥硬化体抗压强度。
The cornstarch sugar alcohol black liquor sulfonated with formaldehyde and Na_2SO_3 solution (molar ratio 0.6-0.8) at 100-140 ℃ and sulfomethylated for 2 ~ 4 hours to prepare lignin-based water reducer, Transform infrared spectroscopy to characterize its structure. The effect of lignin - based water reducer on cement hydration was analyzed by water reduction rate, setting time and compressive strength. The effects of lignin - based water reducer on cement hydration process were also studied by X - ray diffraction and scanning electron microscopy. The results showed that the modified lignin-based water reducer could effectively slow the initial hydration of cement and promote the hydration in the later period, and had good dispersion effect on cement particles. When the water-cement ratio was 0.35 and the dosage was 1.2% Rate of 17.5%, reaching the standard superplasticizer; admixture superplasticizer samples of the initial setting, final setting time were significantly extended, can effectively improve the compressive strength of hardened cement.