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低分子聚醚减缩剂是目前市场上应用最为广泛的一类减缩剂,但其减缩机理尚不明确。选用两亲性二乙二醇单丁醚作为减缩剂,与其分子结构不同但同为两亲性的二丙二醇作为对比样,探索两亲性低分子聚醚减缩机理。通过收缩性能实验表明,二乙二醇单丁醚减少干燥收缩与自收缩的能力明显优于二丙二醇,掺量为2%时,二乙二醇单丁醚与二丙二醇分别减少干燥收缩44.4%与19.2%,减少自收缩73.1%与23.8%。通过等离子光谱（ICP）、有机碳分析仪（TOC）探索了二丙二醇及二乙二醇单丁醚对水泥浆体孔溶液性能的影响,结果表明,减缩能力与减缩剂的分子结构密切相关。水泥水化基本完全后,两亲性二丙二醇与二乙二醇单丁醚不同程度地进入到水泥浆体孔溶液中,28d龄期时使孔溶液中K＋含量分别降低13.8%和35.4%,Na＋含量分别降低15.6%和39.6%,而孔溶液的表面张力也分别降低9.2%与46.2%。由此可见,两亲性减缩剂的减缩能力与其孔溶液中K＋、Na＋浓度成反比且会不同程度地降低孔溶液的表面张力,从而表现出不同的减缩能力。

The low molecular polyether shrinkage reducing agent is most widely used on the market at present,but the shrinkage mechanism is still unclear.In order to explore the shrinkage mechanism of water-soluble polyether,the diethylene glycol monobutylether was selected as shrinkage reducing agent（SRA）,and the dipropylene glycol which has a different structure was used as a contrast sample.The shrinkage performance experiments showed that the diethylene glycol monobutylether reduced the drying shrinkage and the autogenous shrinkage at 28d by about 44.4% and 73.1% while the dipropylene glycol reduced the drying shrinkage and autogenous shrinkage by about 19.2% and 23.8%.The properties of the cement paste’s pore solution were measured by ICP and TOC,and the results showed that the shrinkage reducing ability is closely related to the molecular structure of SRA.The pore solutions are filled with dipropylene glycol and diethylene glycol monobutylether in different concentrations after hydration.The K＋ concentrations of the pore solution were reduced by about 13.8% and 35.4% at 28d by dipropylene glycol and diethylene glycol monobutylether respectively while the Na＋ concentrations were reduced by about 15.6% and 39.6%,and the surface tensions were also reduced by about 9.2% and 46.2%.It can be seen that,for the amphiphilic SRAs,the shrinkage reducing ability is inversely proportional to the K＋,Na＋ concentrations and why they perform different shrinkage reductions is that the pore solutions were filled with them in different amounts which can reduce the surface tension and the K＋,Na＋ concentrations in different degrees.