钾基碱性电解水对粉煤灰混凝土性能的影响

碱性电解水具有高活性、强碱性、强离子性和吸附性等优点。利用碱性电解水作为拌合水制备不同取代率的粉煤灰混凝土,系统研究碱性电解水对粉煤灰混凝土的工作性能、力学性能和抗氯离子渗透性能的影响,并结合X射线衍射仪(XRD)、扫描电镜(SEM)和差热分析试验(TG/DTA)分析碱性电解水混凝土的水化产物及微观结构形貌。结果表明:碱性电解水能够促进混凝土中水泥早期水化反应,改善混凝土的工作性能,除了生成更多的C-S-H凝胶体和Ca(OH)₂等水化产物外,还生成了钾长石,降低了孔隙率,提高结构密实度,改善了混凝土的力学性能和抗渗性能;同时,碱性电解水在一定程度上可以激发粉煤灰的早期活性效应,使得粉煤灰玻璃体网络结构加速断裂,粉煤灰中的SiO₂和Al₂O₃大量溶出与混凝土中的水化产物Ca(OH)₂发生二次反应,生成更多的硅酸钙和铝酸钙等胶凝性产物。相较于普通自来水混凝土,当粉煤灰取代率为20%和30%(质量分数)时,碱性电解水混凝土的56 d抗压强度分别增长了8.7%和3.5%。

Influence of Potassium-Based Alkaline Electrolyzed Water on Performance of Fly Ash Concrete

Alkaline electrolyzed water has the advantages of high activity, strong alkalinity, ionicity and adsorption. Alkaline electrolyzed water was used as mixing water of concrete to prepare fly ash concrete with different replacement ratios. The influence of alkaline electrolyzed water on the workability, mechanical properties and anti-chloride ion permeability performance was studied systemically. Combined with X-ray diffraction analysis (XRD), scanning electron microscope (SEM) and differential thermal analysis experiments (TG/DTA), the hydration products and microstructure morphology of alkaline electrolyzed water fly ash concrete were analyzed. The results show that alkaline electrolyzed water promotes the early hydration reaction of cement in concrete and improves the workability of concrete. In addition to more C-S-H gels, Ca(OH)₂ and other hydration products, the potassium feldspars are also observed, which reduce porosity and improve the compactness of the structure, enhancing the mechanical properties and anti-permeability of concrete. Meanwhile, alkaline electrolyzed water stimulates the pozzolanic effect of fly ash at the early age to a certain extent, which accelerates the fracture of the glass network structure of fly ash in concrete. A large amount of SiO₂ and Al₂O₃ in fly ash dissolve and react with Ca(OH)₂ in concrete to produce more cementitious products such as calcium silicate and calcium aluminate. Compared with ordinary tap water concrete, when the replacement ratio of fly ash is 20% and 30% (mass fraction), the 56 d compressive strength of alkaline electrolyzed water concrete increase by 8.7% and 3.5%, respectively.