再生骨料缺陷与再生混凝土力学性能与渗透性的关系

【作者】 朋改非； 张九峰； 王竞妍；

【机构】 北京交通大学,土建学院；

【摘要】 对高、低两种水胶比(0.255和0.586)再生混凝土(RAC)的力学性能和渗透性进行试验研究。再生骨料由同样两种水胶比的原生混凝土破碎而成,采用热处理方法去除RA表面附着砂浆,对骨料进行吸水率和压碎指标试验,对RAC和天然骨料混凝土(NAC)进行抗压强度、劈裂抗拉强度、断裂能和渗透性试验。结果表明,石子损伤和附着砂浆均对RA吸水率和压碎指标有显著影响;同配合比下,RAC的力学性能比NAC有明显降低;在低水胶比下,附着砂浆的去除导致RAC力学性能降低,但在高水胶比下,附着砂浆的去除则导致RAC力学性能提高;在受压荷载作用下,RAC的氯离子渗透性与NAC有所不同,这可能是RA缺陷导致的,对其机理有待进一步研究。更多还原

【Abstract】 This paper presents an experimental research on mechanical properties and permeability of recycled aggregate concrete(RAC) at low and high water/binder ratios.Concretes at two water/binder ratios(0.255 and 0.586) were broken into recycled aggregates(RA).A type of thermal treatment was employed to remove mortar in RA.Tests were conducted on aggregate to measure water absorption and crushing values,and on RAC and natural aggregate concrete(NAC) to measure compressive strength,tensile splitting strength,and fracture energy.The results revealed that both gravel damage and mortar attached can significantly influence the water absorption and crushing value of RA.The mechanical properties RAC were obviously lower than those of NAC at an identical mix proportion.Moreover the removal of mortar caused a decrease in mechanical properties in the case of low water/binder ratio,but caused an increase in mechanical properties in the case of high water/binder ratio.The behavior of the chloride ion penetration of RAC under compressive loading is different that of NAC,which may be related to the defects of RA.Further experimental research is needed to identify its mechanism.更多还原