改性木质素系外加剂对水泥砂浆性能的影响

研究了改性木质素系外加剂GCL1-M对水泥砂浆物理力学性能和微观结构的影响,结果表明,GCL1－M砂浆减水率达到30%,掺砂浆28天抗压强度比达到了120%。掺GCL1-M砂浆的渗透压力比达到330%,比掺CLS的砂浆提高了1倍多。氮吸附测试和电子扫描显微观测等结果表明,GCL1-M减慢了水泥水化反应放热速度,降低砂浆的总孔容积,阻塞毛细管通道,提高砂浆的抗渗能力。吸附性能、Zeta电位及环境扫描电镜测试结果表明,GCL1－M在水泥颗粒表面形成网状结构吸附,增加了颗粒间的静电斥力位能,增强了对水泥砂浆的分散和保水作用,有利于提高水泥砂浆的抗渗性能和抗压强度。

Effect of Modified lignosulfonates additive on the properties of cement mortar

A modified lignosulfonates high-performance mortar additive GCL1-M was prepared by oxidation sulfomethylation and polycondensation from Calcium lignosulfonates (CLS). The water-reducing ratio of GCL1-M reaches 30%. The 28-day compressive strength ratio added GCL1-M reaches 120% and is 2.32 times more than that of CLS at the dosage of 0.3%. By measuring the temperature raising curve of cement paste, the pore distribution of mortar and SEM, the results show that GCL1-M can delay the heat releasing of cement hydration remarkably and diminish the pore volume and pore diameter of hydrated cement, to improve the resistances to cracking and seepage of mortar. The effect of GCL1-M on performance of mortar was investigated by measuring the adsorption amounts and the zeta potentials in the surface of cement. The results showed that the dispersive mechanism of GCL1-M on cement is due to the lubrication action of air-entraining and improving the static repelling force of cement. GCL1-M absorbs on the surface of cement and forms network configuration to improve the water retention of mortar.