不同养护时间下蒸养混凝土裂缝扩展阻力研究  

Crack extension resistance of steam-cured concrete under different curing time

作　　者：娄本星 胡少伟 叶宇霄 LOU Benxing;HU Shaowei;YE Yuxiao(Nanjing Hydraulic Research Institute,Nanjing 210029,China;College of Civil Engineering,Chongqing University,Chongqing 400045,China)

机构地区：[1]南京水利科学研究院,江苏南京210029 [2]重庆大学土木工程学院,重庆400045

出　　处：《混凝土》2022年第2期22-25,30,共5页Concrete

基　　金：国家自然科学基金重点项目(51739008);国家重大科研仪器研制项目(51527811)。

摘　　要：采用三点弯曲梁试验,基于虚拟裂缝模型和试验测得的P-CMOD曲线,计算得到了不同蒸养时间下混凝土试件的裂缝扩展阻力曲线和应力强度因子曲线,分析了养护时间对蒸养混凝土早期裂缝扩展阻力的影响。结果表明:随着养护时间的增加,KR阻力曲线与材料的力学性能均呈先升高后降低的趋势;试件的稳定性分析与双K断裂准则在原理上是相同的,起裂韧度和失稳断裂韧度是KR(Δa)阻力曲线上的两个关键点;断裂过程区(FPZ)长度对K;阻力曲线有重要影响,养护时间从4~16 h,FPZ长度从49 mm降至45 mm,养护时间超过16 h后,FPZ长度变化不大。Based on the fictitious crack model and the P-CMOD curve recorded in the experiment,the crack extension resistance curves(KR-curves)and stress intensity factor curves of three-point bending(TPB)specimens under different curing time were calculated.Then,the effects of curing time on KR-curves of steam-cured concrete were analyzed.The results indicate that the KR-curves became higher first and then became lower.The stability analysis are identical with the double K criterion,and the initial fracture toughness and the unstable fracture toughness are two key points on the KR-curve.The FPZ length has an important influence on the KRcurve,and it decreases from49 mm to 45 mm with curing time increasing in 16 h followed by a stable trend when the curing time beyond 16 h.

关 键 词：蒸养混凝土 养护时间 裂缝扩展阻力 FPZ长度 

分 类 号：TU528.064[建筑科学—建筑技术科学]