聚羧酸减水剂对大掺量粉煤灰自密实混凝土水硬化性能的影响  

Effect of Polycaoboxylate Superplasticizer on High-Volume Fly Ash Self-Compacting Concrete Hydration Hardening Performance

作　　者：龚明子[1] 陈龙[1] 蒋亚清[1] 

机构地区：[1]河海大学材料科学与工程学院,南京213022

出　　处：《粉煤灰》2009年第4期11-13,共3页Coal Ash China

摘　　要：通过SEM观察和氮吸附试验,对标准养护3d、7d和28d掺马来酸类聚羧酸减水剂的大掺量粉煤灰自密实混凝土(HVFASCC)的水化硬化性能、微观形貌、孔隙特性和强度发展进行了研究。结果表明,马来酸类聚羧酸减水剂促进了C3A水化进程,3d时可观察到大量AFm与AFt共存;同时发现,粉煤灰-基材存在次生界面过渡区,其特征与粗集料-基材接口过渡区类似,但随水化进程发展逐步消失;聚羧酸减水剂与大掺量粉煤灰提高了混凝土的匀质性,改善了水泥石孔结构,且随龄期增长,大孔减少,小孔增多,混凝土强度稳步增长。马来酸类聚羧酸减水剂促进了水泥早期水化,弥补了确良HVFASCC早强低的性能缺陷,掺马来酸类聚羧酸减水剂的HVFASCC微观结构致密,可在混凝土结构中应用。In order to investigate the influence of polycarboxylate-based superplasticizer on the hydration of the high volume fly ash self-compacting concrete (HVFA SCC), micro-morphology, characteristics of porosity and the development of strength of HVFA SCC mixed with polycarboxylate-based superplasticizer at curing age of 3d, 7d and 28d were studied by SEM and nitrogen absorption tests. The results show that maleic anhydride type polycarboxylate-based superplasticizer speeds up the hydration rate of C3A, and a large volume of AFm was observed to coexist with AFm at 3d. Also, the second interfacial transition zone (ITZ) between fly ash and cement matrix is distinguished, its characteristics were similar to that between coarse aggregate and cement matrix. With the development of hydration process, the ITZ will gradually disappear. The Polycarboxylate-based superplasticizer and high volume of fly ash can improve the pore structure of cement paste, and strength of concrete grows steadily up with the increase of curing age. The maleic anhydride type polycarboxylate-based superplasticizer accelerates the hydration degree of cement and makes up the lower early strength of HVFA SCC. HVFA SCC mixed with polycarboxylate-based superplasticizer has denser microstructure, which can be applied for structural concrete.

关 键 词：大掺量粉煤灰自密实混凝土 聚羧酸减水剂 钙矾石 界面过渡区 氮吸附 

分 类 号：TQ528.57[化学工程—煤化学工程]