粉煤灰地聚合物混凝土的制备、特性及机理

Preparation, Properties and Mechanism of Fly Ash Based Geopolymer Concrete

利用粉煤灰作为配制地聚合物的一种基本Si Al质材料,以强度为指标寻求最佳地聚合物配比;为优化养护制度,采用了标准养护、蒸汽养护、压蒸养护3种养护制度,从中选出了最有利于发挥胶凝材料活性的养护制度.实验表明,当粉煤灰掺量为30%,80°C下蒸养8h时抗压和抗折强度达到最优,分别为32.2和7.15MPa.将最优的地聚合物胶结材制成混凝土,并对其抗氯离子渗透、抗冻融性能进行了研究,发现其具有非常优异的耐久性.利用红外、X射线衍射对地聚合物的形成机理及结构本质进行的分析发现,地聚合物在合成过程中SiO4对应的1086cm-1红外振动峰向低波数偏移,6配位Al也转化为4配位,最终形成无定形态的结构物质.

Fly ash was used as a basic SiAl ingredient of geopolymer. The amount of fly ash and 3 types of curing methods were investigated to obtain the optimum strength of flexural and compressive. The results show that geopolymer containing 30% fly ash which was prepared at 80 °C for 8 h exhibites high strength. The compressive and flexural strength of the fly ash based geopolymer were 32.2 MPa and 7.15 MPa, respectively. Study of Cl- permeability, freezing and thrawing behavior show that the fly ash based geopolymer concrete has very excellent durability. Infrared spectrum and Xray diffraction measurements show that IR peak at 1 086 cm-1 caused by the stretching vibration of SiO4 tetrahedra shiftes to lower wavenumber around 1 033 cm-1, and the 6fold Al is transformed into 4fold coordination during the synthesis of geopolymer. As a result, the amorphous geopolymer is formed.