废弃结构混凝土粉料胶凝特性的研究

Research on Cementitious Characteristics of Waste Structure Concrete Powder

废弃混凝土类建筑垃圾经过破碎、筛分、二次破碎和研磨等预处理后,可作为再生胶凝材料替代水泥。采用盐和碱对其活性进行激发,研究了废弃混凝土类建筑垃圾的胶凝特性。采用抗压强度、抗折强度、XRD、TG-DSC-DTC和SEM对试样的力学性能和微观结构进行了测试。试验结果表明,废弃混凝土类建筑垃圾具有潜在活性,激发剂可以明显提高其活性。单一激发效果不明显,盐激发和碱激发复合激发效果较好,可以促使其进行水化,提高体系的强度。从微观测试可以看出,掺入复合激发剂的试样中钙矾石等水化产物较多,结构致密,说明水化比较充分。

Concrete construction waste can be used as regenerated cementitious material instead of cement through crushing, screening, secondary crushing and grinding pretreatment. Using salt and alkali to stimulate the activity of regenerated cementitious material, the gelling characteristics of concrete construction waste are researched. Compressive strength, flexural strength, X-ray diffraction, thermogravimetry-differential scanning calorimetry, scanning electron microscopy are used to investigate the mechanical properties and microstructure of specimens. The experimental results show that concrete construction waste has potential activity and the activator can greatly improve its activity. Composite activator of salt and alkali has good effect compared to single activator. Composite activator can promote hydration and improve the system strength. Samples doped with composite activator have more ettringite and compact structure through micro-test, which indicate that the samples have full hydration.