引气剂液膜单分子层及硬化混凝土气孔结构分析

利用膜天平研究了两种引气剂GYQ和改性松香R在空气-水界面的液膜单分子层强度,采用光学显微镜测孔法分析了硬化引气混凝土的气孔结构,并考察了高频振捣对掺2种引气剂的混凝土气孔结构的影响。结果表明,引气剂在空气-水界面上的单分子膜强度是影响引气剂稳泡性能的重要参数之一。掺加稳泡性能优异的高性能引气剂,可以在混凝土中引入更加细小、稳定、分布合理的气泡,硬化混凝土具有更优化的气孔结构。高频振捣破坏了混凝土中的大直径气泡,合理的振捣时间优化了混凝土的气孔结构。

Anlysis of Monolayer of Air-Entraining Agent and Air Void Characteristics of Harden Concrete

Monolayer of two kinds of air-entraining agent GYQ and modified rosin R are formed in KSV 2000 Langmuir min-trough at air-water interface,respectively.The surface pressure of each monolayer is measured using the wilhelmy plate technique.The static surface elasticity of monolayer at air-water interface are discussed by analyzing the π-A isotherm.The air void characteristics of hardened concrete are determined by automated linear traverse method with image processing system based on ASTM C 457.It＇s found that the performance of air bubble stability of air-entraining admixtures is determined directly by the strength of monolayer at air-water interface.Comparing with the air void characteristics of hardened concrete produced by air-entraining admixtures,higher strength of GYQ monolayer resulted in the smaller spacing factors and more excellent air void characteristics.The bigger air bubbles were broken by the method of high frequency vibration,the air void characteristics of harden concrete were optimized by reasonable time of high frequency vibration.