废弃混凝土再生粉的胶凝性试验研究

Experimental Study on Cementation of Recycled Waste Concrete Powder

通过研究,设计出满足42.5级普通硅酸盐水泥力学性能要求的配合比,探讨混凝土再生粉及MgO掺量对砂浆力学性能的影响,并采用吸水动力学法测定砂浆不同吸水时间吸水率及孔结构参数,同时测定砂浆高温后的残余力学性能。结果表明:增加混凝土再生粉掺量,抗折、抗压强度减小,砂浆耐高温性能则有所提高。降低混凝土再生粉掺量或增加MgO掺量有利于改善砂浆孔径分布,细化孔结构。MgO对砂浆抗折、抗压强度有促进作用,且早期作用较为显著,后期影响较小,但降低了砂浆耐高温性能。

Through the research,the mixture ratio which can meet the mechanical performance requirements of 42. 5 grade ordinary portland cement was designed,and the influence of recycled concrete powder and MgO content on the mechanical properties of mortar was discussed. The water absorption rate and pore structure parameters of mortar at different water absorption times were measured by the method of water absorption dynamics,and the residual mechanical properties of mortar after high temperature were also measured. The results showed that when increasing the amount of recycled concrete powder,the flexural strength and compressive strength decreased,while the high temperature resistance of mortar was improved. And the decrease of recycled concrete powder content or the increase of MgO content could improve the pore size distribution of mortar and refine the pore structure. MgO could promote the flexural strength and compressive strength of mortar,and the effect was more obvious in the early stage and less in the later stage,but it reduced the high temperature resistance of the mortar.