聚羧酸减水剂吸附行为及其对水泥浆体流动性的影响研究  

Study on Adsorption Behavior of Polycarboxylic Acid Superplasticizers and Their Effects on the Fluidity of Cement Slurry

作　　者：赵慧 ZHAO Hui(China Railway Urban Construction Group 1st Engineering Co.Ltd.,Taiyuan Shanxi 030024,China)

机构地区：[1]中铁城建集团第一工程有限公司,山西太原030024

出　　处：《铁道建筑技术》2024年第11期41-44,共4页Railway Construction Technology

基　　金：中铁城建集团有限公司科技研究开发计划项目(ZTCJZ-2018-06)。

摘　　要：通过合成主链长度、侧链长度、侧链密度及主链电荷密度不同的一系列PC减水剂,对聚羧酸(PC)减水剂分子结构、在水泥颗粒表面的吸附行为及水泥浆体的流变性能的关系进行了研究。测试了不同掺量下水泥浆体的流动扩展度,确定了每一种PC减水剂的临界掺量,当掺量大于临界掺量后,水泥浆体达到最大流动度,且最大流动度与PC分子结构无关。针对PC减水剂在水泥颗粒表面的吸附行为采用总有机碳测试法(TOC)进行了研究,结果表明PC分子为典型的Langmuir单分子层吸附,其驱动力为电荷相互作用。水泥浆体的流动扩展度与PC在水泥颗粒表面的吸附量相关,在PC减水剂掺量超过临界掺量后,尽管水泥颗粒表面的吸附量仍然增大,但水泥浆体的流动扩展度保持不变,分析认为PC减水剂的临界掺量代表使水泥浆体中絮凝结构最大程度解体所需要的PC掺量,此时吸附的PC分子在水泥颗粒表面的覆盖率均约为30%,与PC减水剂分子结构无关。In this paper,a series of PC superplasticizers with different main chain length,side chain length,side chain density and main chain charge density were synthesized to study the relationship between the molecular structure of polycarboxylic acid(PC)superplasticizer,the sorption on the face of cement granules and the rheology of cement slurry.The flow expansion degree of the slurry with different dosage was tested,and the critical dosage of each PC water-reducing agent was determined,when the dosage is greater than the critical dosage,the cement slurry reaches the maximum fluidity,and the maximum fluidity is independent of the molecular framework of PC.The sorption of PC superplasticizer on the face of cement granules was studied by total organic carbon test(TOC).The results show that PC molecules are typical Langmuir monolayer adsorption,and the driving force of adsorption is charge interaction.The flow expansion of cement slurry correlates with the PC sorption amount on the cement granules,when the content of PC superplasticizer exceeds the critical content,although the adsorption on the surface of cement particles still increases,the flow expansion degree of cement slurry remains unchanged.The analysis shows that the critical content of PC superplasticizer represents the amount of PC required to disintegrate the flocculating structure in the cement slurry to the maximum extent.At this time,the ground coverage of adsorbed PC molecules on the cement granules is about 30%,which has nothing to do with the molecular structure of PC superplasticizer.

关 键 词：水泥 聚羧酸减水剂 絮凝结构 临界掺量 覆盖率 

分 类 号：TU582.042[建筑科学—建筑技术科学]