<正>结合高速公路桥梁施工的经验，从混凝土的内在质量、模板及支架工艺、钢筋制作安装、混凝土浇筑及构件成品保护5个方面，分析了现浇箱梁混凝土（砼）外观质量的控制措施。

Cationic lignin surfactant was synthesized by reacting alkali lignin with quaternary ammonium salt 3-chloro-2-hydroxypropyl-trimethyl ammonium chloride (CHPTMAC). The effects of CHPTMAC dosage, NaOH dosage, reaction temperature and reaction time on the surface activity, nitrogen content and solubility of cationic lignin surfactants were studied. The results showed that the suitable synthesis conditions of cationic lignin surfactant were as follows: the dosage of quaternary ammonium salt (CHPTMAC) was 4mol/kg, the molar ratio of NaOH to quaternary ammonium salt agent was 1.3, reaction temperature was 50℃, and reaction time was 4h. Synthesized cationic lignin surfactant had good solubility under different pH value, nitrogen content and surface tension of the surfactant were 2.53% and 42.9mN/m, respectively.