煤矸石胶凝材料水化产物及聚合度分析

^(29)Si polymerization degree of hydrates in coal gangue added cement

采用XRD,IR和NMR等分析方法研究北京房山煤矸石在水化过程中的物相及29Si聚合度的变化规律。在29Si NMR基础上提出利用相对桥氧数(RBO)评价硅氧多面体聚合度的方法,并用该方法研究煅烧煤矸石在活化及水化前后的RBO变化规律。研究结果表明:煤矸石中的粘土矿物绿泥石和白云母等在活化过程中发生分解,表征硅氧多面体聚合度的指标RBO明显降低;而在水化过程中随着水化龄期的增加,氢氧化钙不断与硅铝质物料中的[SiO4]和[AlO4]四面体发生反应,生成水钙沸石和碳硅钙石,导致RBO升高,浆体材料的结构致密性增加。这表明煤矸石中的[SiO4]聚合度在煅烧活化过程中由高聚合度向低聚合度转变,在水化过程中则由低聚合度向高聚合度转变,聚合度或RBO的变化在一定程度上反映活化效果和胶凝活性的发挥程度。

XRD,IR and NMR technique were used to study phase transition and 29Si polymerization degree of hydrates in coal gangue added cement.A new method of the relative bridge oxygen（RBO） was proposed based on NMR technique to evaluate the polymerization degree of 29Si in thermo activated coal gangue and hydrates of gangue added cement.The results show that the clay minerals such as leuchtenbergite and muscovite decompose and the RBO correspond to degree of polymerization decreases in thermo-active process.But in hydration process calcium hydroxide reacts with and tetrahedron which make calcium hydroxide phase decrease and generate gismondinte and larnite. polymerize to each other and RBO increases significantly.Meanwhile the density of paste increases with hyaration age.So the thermo-activation and hydration is the process of depolymerization and polymerization respectively.The changes of 29Si polymerization degree-RBO can be used to evaluate the coal gangue cementitious activity or hydration degree.