不同养护条件下混凝土断裂性能的试验研究

Experimental study on the fracture toughness of concrete under different curing conditions

应用RILEM推荐的双参数模型,确定两种不同配合比混凝土NSC,HSC在不同养护条件下的临界应力强度因子KSIC和临界裂缝尖端张开位移CTOD。标准养护的时间分别为0天,2天,6天和27天,试验龄期均为28天。文章同时给出相应的抗压强度、弹性模量以及抗拉强度。试验结果表明,抗压强度、弹性模量、抗拉强度以及临界应力强度因子随标准养护时间的增长而增大,弹性模量对养护条件的敏感性最大。无论是NSC还是HSC,标准养护6天的力学参数都能达到标准养护27天的90%左右。试验结果还表明虚拟裂缝模型中定义的特征长度lch可以作为混凝土脆性大小的判断依据。

Two-parameter model proposed by RILEM was applied to determine the critical stress intensity factor K^s_(IC) and critical crack tip opening displacement of NSC and HSC under difference curing conditions.Standard curing periods were respectively 0,2,6,27days,trial age was 28 days.The compressive strength,splitting tensile strength and elastic modulus were provided simultaneously.The test results show that the longer the time of moist curing,the higher the values of compressive strength,splitting tensile strength,elastic modulus and critical stress intensity factor.No matter what it is,NSC or HSC,at the 6th day.All mechanical parameters can reach around 90% of 27 day' moist curing.The characteristic length determined in the fictitious crack model proves to be a good indication of brittleness in concrete in the result.