浅析泥土对不同结构聚羧酸减水剂的吸附规律

目前,混凝土减水剂主要以聚羧酸和萘系两种为主。聚羧酸减水剂(PCEs)在应用过程中对泥土过于敏感,性能急剧下降,而萘系具有很好的抗泥性,这也是萘系减水剂在砂石含泥量较高的商砼领域一直占据主导地位的重要原因。要在商砼领域大规模推广聚羧酸减水剂,增强其抗泥性是关键所在。利用紫外可见吸收光谱分析手段,研究泥土对不同结构的聚羧酸减水剂的吸附规律,并且研究了聚羧酸减水剂对不同含泥量砂浆的分散性能,实验发现水泥浆显著提升了泥土对聚羧酸减水剂的饱和吸附量,并初步发现短主链、短侧链的聚羧酸减水剂抗泥效果相对较好。

Analysis on Absorption Rule of Polycarboxylate Superplasticizers with Various Structures in Clay

At present, there are mainly two kinds of concrete water-reducing agents—polycarboxylate superplasticizer（PCEs） and naphthalene formaldehyde condensate（SNF）. PCEs often suffers a sharp drop in the properties due to its over sensitivity to clay, while SNF enjoys a dominant share in the field of commercial concrete with high clay content because of its better clay adaptability than PCEs. In order to expand the market share of PCEs, it is critical to improve its anti-clay performance. In view of this, the rule of clay adsorbing PCEs with different structures was studied by UV-absorption spectrum analysis. The dispersion performance of PCEs to different clay-content mortars was also studied and it was found that cement slurry significantly increased the saturated adsorption capacity of PCEs. It also showed that the PCEs with shorter main chain and side chain had better anti-clay effects.