减缩剂与减水剂的相容性研究

研究了两种减缩剂与四种减水剂复合后对溶液表面张力、混凝土坍落度、混凝土强度、混凝土自由收缩和砂浆收缩的相容性问题.试验结果表明,两种自身表面张力相近的减缩剂对蒸馏水和减水剂溶液表面张力的作用差异较大,但对砂浆和混凝土的减缩率几乎相同,收缩规律的影响相似,说明表面张力并不是减缩率的惟一决定因素.就减缩率而言,减缩剂与减水剂的相容性是较好的,而对强度的相容性相对较差,其作用机理与减水剂分子的支链数及负离子基团数有关.

Investigation on compatibility of shrinkage-reducing agent and superplasticizer

Investigation was carried out on the compatibility between two shrinkage reducing agents and four superplasticizers on the solution surface tension, the slump, strength, free shrinkage of concrete and mortar. Test results showed that the two different type shrinkage reducing agents, with similar surface tension themselves, have different effects on the surface tension in distilled water and superplasticizer solvent. But the shrinkage reducing ratio and the shrinkage mode of concrete of these two shrinkage reducing agents were the same. These results mean that the surface tension is not the only determinant factor on the shrinkage-reducing ratio. The compatibility is preferable for shrinkage reducing ratio and is faintish for strength for shrinkage reducing agent with superplasticizer mixed. The action mechanism is probably related the number of branches and anion groups of the superplasticizer.