改性毛杨梅栲胶减水分散性能研究

Study on Water-Reducing and Dispersing Performances of Modified Myrtan Tannin Extract

研究磺化改性毛杨梅栲胶对水泥的减水分散性能。结果表明:当水泥中栲胶和改性栲胶的掺加质量分数为0.5%,混凝土减水率分别为7.1%和13.1%,掺改性栲胶的水泥净浆初凝和终凝时间比掺栲胶的净浆分别缩短3h 15min和8h 50min;栲胶磺化改性后表面活性下降,基本失去起泡能力;栲胶和改性栲胶质量浓度为2.0g·L-1时,在水泥颗粒表面的平均吸附量分别为7.39和5.91mg·g-1;栲胶和改性栲胶质量浓度均为1.0g·L-1时,在水泥颗粒表面的ξ-电位分别为-22.13和-25.53mV。故栲胶磺化改性后对水泥的减水分散能力增强。

Tannin extract is traditional forest chemical product in China, their demand now is decreasing, and it is essential to develop new use. The modification of myrtan tannin extract and the dispersing performances of modified myrtan tannin extract to cement were studied. The results indicated that when the mass fractions of tannin extract and modified tannin extract to cement were 0.5 %, the water-reducing rate of concrete was 7.1% and 13.1% respectively, and the initial and final setting time of cement paste added modified tannin extract was shorter 3 h 15 min and 8 h 50 min respectively than that of cement paste added tannin extract. The surface activity of modified tannin extract was less than unmodified, and the modified tannin extract almost lost its foaming capability. When the mass concentrations of modified tannin extract and tannin extract were 2.0 g·L^-1, their adsorptive amount on surface of cement particles was 7.39 和 5.91 mg·g^-1 respectively. When the mass concentrations of modified tannin extract and tannin extract were 1.0 g· L^-1, the ξ-potentials on surface of cement particles added tannin extract and modified tannin extract was - 22.13 and - 25.53 mV respectively. Therefore the water-reducing and dispersing capability of tannin extract to cement increased significantly after being modified.