摘要
系统研究了硫酸盐对掺聚羧酸减水剂水泥浆体流变性及水化性能的影响.结果表明:硫酸盐降低了聚羧酸减水剂在水泥颗粒表面的吸附量,削弱了聚羧酸减水剂对水泥浆体的分散作用.随着硫酸盐掺量的增加,聚羧酸减水剂分散性能下降.少量硫酸盐延缓了水化加速期最大水化放热速率峰的出现,并且提高了最大水化放热速率.而大量硫酸盐则使得水泥水化诱导期缩短,最大水化速率峰显著提前.大量硫酸盐的加入促进了水泥浆体中钙矾石(AFt)的生成,削弱了水化铝酸钙(CAH)的生成.MgSO4对于水泥浆体中水化产物生成的促进作用最明显.掺加MgSO4的水泥水化产物中含有大量细丝状水化硫铝酸盐产物.MgSO4对水泥水化具有显著延缓作用,水化产物结晶成核作用较缓慢,从而使得水化产物生成及分布更加均匀,形状更加细小.
The effects of sulfates on the adsorption and dispersing properties of cement paste of polycarboxylate （PCE） superplasticizer were studied. The effects of sulfates on the hydration process of cement paste were systematically investigated through isothermal calorimetry as well as scanning electron microscope （SEM）. The results show that the addition of sulfates reduces the adsorption of PCE on cement particles and hence impairs the dispersing capability of PCE. Among the sulfates, alkali sulfates （Na2 S04 and Ks S04 ） most significantly influence the dispersing capability of PCE, while the poorly soluble CaSO4 ~ 2H2 0 slightly influences the dispersing capability of PCE. A small amount of sulfates retards induction period, promotes the maximum hydration rate, and increases the heat evolution rate due to the transformation from ettringite （AFt） to mono calcium aluminate （AFro）. A high amount of sulfates significantly advances the maximum hydration rate peak at acceleration period, promotes the formation of AFt, and impairs the formation of hydrated calcium aluminate （CAH）. Among the sulfates, the addition of MgS04 greatly retards the hydration heat peak at acceleration period and significantly promotes the transformation from AFt to AFm. Mter cement paste is hardened, a large number of filamentous hydrated sulphoaluminate phases are present due to the addition of MgSO4, because MgSO4 greatly retards the hydration process and slows the nucleation and precipitation of hydration products.
作者
何燕
张雄
张永娟
洪万领
HE Yah ZHANG Xiong ZHANG Yongjuan HONG Wanling(School of Material Science and Technology, Tongji University, Shanghai 201804, China Key Laboratory of Advanced CiVil Engineering Materials of the Ministry of Education, Tongji University, Shanghai 201804, China)
出处
《同济大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2017年第2期230-234,共5页
Journal of Tongji University:Natural Science
基金
国家自然科学基金(No.51378391)
"十三五"国家重点研发计划(2016YFC0700800)
关键词
硫酸盐
水泥
聚羧酸减水剂
分散性能
水化性能
sulfates
cement
polycarbexylate superplasticizer
dispersing properties
hydration properties
