摘要
为研究不同胶结剂和骨料类型对混凝土受压疲劳性能的影响,采用3种胶凝材料:普通硅酸盐水泥(ordinary portland cement,OPC);由30%OPC,20%粉煤灰(fly ash,FA)和50%磨细矿渣(ground granulated blast-furnace slag,GGBS)组成的高掺量辅助胶凝材料(supplementary cementitious material,SCM);由50%FA和50%GGBS组成,并掺入Na_(2)SiO_(3)和Ca(OH)_(2)的碱激发剂胶凝材料(alkali-activator,AA),试验制作了天然骨料混凝土(normal-weight concrete,NWC)和轻质骨料混凝土(light-weight concrete,LWC),开展恒应力循环压缩试验。最大应力水平设置3个等级,分别为混凝土静态单轴抗压强度的75%,80%和90%,而最小应力水平固定为静态抗压强度的10%。基于对试验结果的回归分析,建立了疲劳寿命和疲劳应力-应变曲线模型。结果表明,LWC的疲劳寿命略低于NWC,LWC的疲劳应变高于NWC,且与OPC混凝土相比,对于SCM或AA混凝土以上规律更加凸显。本文提出的不同胶结剂和骨料类型混凝土的改进疲劳应力-应变模型,具有计算精度高、计算过程简单、不需要繁琐迭代计算的优势。研究成果可为预测轻骨料混凝土疲劳应力-应变曲线及疲劳寿命提供一套新的方法。
To evaluate the effect of different binders and aggregate types on the compressive fatigue performance of concrete,three types of cementitious materials were used in the experiment:ordinary Portland cement(OPC);a high content supplementary cementitious material(SCM)composed of 30%OPC,20%fly ash(FA),and 50%ground granulated blast-furnace slag(GGBS);a base activator cementitious material(AA)composed of 50%FA and 50%GGBS,mixed with Na_(2)SiO_(3) and Ca(OH)_(2).Normal-weight concrete(NWC)and light-weight concrete(LWC)were tested and subjected to constant stress cyclic compression tests.The maximum stress level was set at three levels,which were 75%,80%,and 90% of the static uniaxial compressive strength of the concrete,while the minimum stress level was fixed at 10% of the static compressive strength.Based on regression analysis of experimental results,fatigue life and fatigue stress-strain curve models were established.The results show that the fatigue life of LWC is slightly lower than that of NWC,and the fatigue strain of LWC is higher than that of NWC.Compared with OPC concrete,the above rules are more prominent for SCM or AA concrete;The improved fatigue stress-strain models proposed in this article for concrete with different types of binders and aggregates have high calculation accuracy,simple calculation process,and do not require tedious iterative calculations.The research results can provide a new method for predicting the fatigue stress-strain curve and fatigue life of lightweight aggregate concrete.
作者
马俐
韦向高
张秋霞
MA Li;WEI Xianggao;ZHANG Qiuxia(Management Engineering Department,Xuanhua Vocational College of Science and Technology,Zhangjiakou 075000,Hebei,China;College of Civil Engineering and Architecture,Guangxi University,Nanning 530004,China;Sichuan Highway Planning,Survey,Design and Research Institute Company Limited,Chengdu 610041,China)
出处
《力学与实践》
2024年第4期759-767,共9页
Mechanics in Engineering
基金
四川省科技厅重点研发项目(2020YFS0361)资助。
关键词
恒应力循环压缩
轻骨料混凝土
胶凝材料
应力-应变曲线
疲劳寿命预测模型
constant stress cyclic compression
light-weight concrete
cementitious materials
stress-strain curve
fatigue life prediction model
