In order to clarify the fatigue damage evolution of concrete exposed to flexural fatigue loads,ultrasonic pulse velocity(UPV),impact-echo technology and surface electrical resistance(SR) method were used.Damage variab...In order to clarify the fatigue damage evolution of concrete exposed to flexural fatigue loads,ultrasonic pulse velocity(UPV),impact-echo technology and surface electrical resistance(SR) method were used.Damage variable based on the change of velocity of ultrasonic pulse(Du) and impact elastic wave(Di)were defined according to the classical damage theory.The influences of stress level,loading frequency and concrete strength on damage variable were measured.The experimental results show that Du and Di both present a three-stages trend for concrete exposed to fatigue loads.Since impact elastic wave is more sensitive to the microstructure damage in stage Ⅲ,the critical damage variable,i e,the damage variable before the final fracture of concrete of Di is slightly higher than that of Du.Meanwhile,the evolution of SR of concrete exposed to fatigue loads were analyzed and the relationship between SR and Du,SR and Di of concrete exposed to fatigue loads were established.It is found that the SR of concrete was decreased with the increasing fatigue cycles,indicating that surface electrical resistance method can also be applied to describe the damage of ballastless track concrete exposed to fatigue loads.展开更多
用X射线光电子能谱(XPS)对热处理煤矸石中Si 2p,A l 2p和O 1s的结合能进行试验研究,发现煤矸石质硅铝基胶凝材料的强度和煤矸石中硅、铝的结合能具有线性关系,煤矸石的硅、铝结合能可以用来表征煤矸石的胶凝特性和活性.热活化煤矸石Si 2...用X射线光电子能谱(XPS)对热处理煤矸石中Si 2p,A l 2p和O 1s的结合能进行试验研究,发现煤矸石质硅铝基胶凝材料的强度和煤矸石中硅、铝的结合能具有线性关系,煤矸石的硅、铝结合能可以用来表征煤矸石的胶凝特性和活性.热活化煤矸石Si 2p,A l 2p和O 1s的结合能之间具有很好的相关性.基于此提出硅铝质物料活性评价的新方法———用Si,A l表面结合能评价硅铝质物料活性.展开更多
基金Funded by the National Natural Science Foundation of China(Nos.U1934206,52208299,and 52108260)the 2021 Tencent XPLORER PRIZE。
文摘In order to clarify the fatigue damage evolution of concrete exposed to flexural fatigue loads,ultrasonic pulse velocity(UPV),impact-echo technology and surface electrical resistance(SR) method were used.Damage variable based on the change of velocity of ultrasonic pulse(Du) and impact elastic wave(Di)were defined according to the classical damage theory.The influences of stress level,loading frequency and concrete strength on damage variable were measured.The experimental results show that Du and Di both present a three-stages trend for concrete exposed to fatigue loads.Since impact elastic wave is more sensitive to the microstructure damage in stage Ⅲ,the critical damage variable,i e,the damage variable before the final fracture of concrete of Di is slightly higher than that of Du.Meanwhile,the evolution of SR of concrete exposed to fatigue loads were analyzed and the relationship between SR and Du,SR and Di of concrete exposed to fatigue loads were established.It is found that the SR of concrete was decreased with the increasing fatigue cycles,indicating that surface electrical resistance method can also be applied to describe the damage of ballastless track concrete exposed to fatigue loads.
文摘用X射线光电子能谱(XPS)对热处理煤矸石中Si 2p,A l 2p和O 1s的结合能进行试验研究,发现煤矸石质硅铝基胶凝材料的强度和煤矸石中硅、铝的结合能具有线性关系,煤矸石的硅、铝结合能可以用来表征煤矸石的胶凝特性和活性.热活化煤矸石Si 2p,A l 2p和O 1s的结合能之间具有很好的相关性.基于此提出硅铝质物料活性评价的新方法———用Si,A l表面结合能评价硅铝质物料活性.
