经不同高温历程后高强混凝土的受压疲劳性能研究

发布时间：2018-04-19 14:22

  本文选题：高强混凝土 + 高温历程　； 参考：《北京建筑大学》2017年硕士论文

【摘要】：随着经济的飞速发展,高强混凝土材料越来越广泛应用于现代建筑中,例如央视文化中心、沈阳皇朝万鑫酒店等。然而建筑结构火灾问题也日益突出,建筑物遭受火灾等高温后,混凝土结构会产生一系列物理化学变化,由此造成结构性能受到不同程度的劣化,特别是高强混凝土的高温爆裂,突然性且破坏性大,加剧了结构的损伤。对于央视文化中心等使用高强混凝土材料的工程结构,有时会遭受火灾或其他高温历程,有时会遭受地震等反复荷载的作用,目前尚不具备对现场工程中混凝土结构剩余抗震能力或抗疲劳性能进行估计,导致最后的评估结论及加固方案存在隐患。因此有必要研究经不同高温历程后高强混凝土宏观力学性能及疲劳损伤的变化规律。本文利用箱式电阻炉、电液伺服万能试验机、电液伺服疲劳试验机等综合手段,对经不同高温历程后高强混凝土的性能变化(主要是疲劳性能)进行分析,并建立高温历程与高强混凝土力学性能的关系模型。通过对经历高温的高强度混凝土的抗压强度试验及疲劳试验,进一步建立高温历程与高强混凝土疲劳损伤的关系模型,形成研究高强混凝土材料高温历程、力学性能及疲劳损伤之间关系的科学方法。对经不同高温历程后C60高强混凝土的力学性能及疲劳损伤进行了研究,包括不同高温历程后高强混凝土剩余强度、质量、弹性模量、峰值应变及疲劳寿命、疲劳总应变、残余应变、疲劳损伤等的变化情况。然后进行温度历程与高强混凝土力学性能研究,相比普通混凝土,高强混凝土经不同高温历程后的力学性能损失较大,其特点在500℃范围内明显不同于普通混凝土;快速升温发生爆裂现象,远低于普通混凝土800℃的爆裂温度,表现出更脆性。对高温历程与力学性能参数进行相关性分析,在相关性良好的基础上建立高温历程-剩余强度、高温历程-弹性模量、高温历程-峰值应变、高温历程-疲劳寿命、高温历程-疲劳总应变、高温历程-疲劳残余应变与高温历程-疲劳变形模量等数学关系模型。分别利用疲劳变形模量比与相对残余应变作为损伤变量,建立高温历程、力学性能与疲劳损伤的关系模型,模型既能科学定性地描述高强混凝土材料在高温后的力学性能特征,又能准确定量反映高温历程与受压疲劳损伤的关系。
[Abstract]:With the rapid development of economy, high-strength concrete materials are more and more widely used in modern buildings, such as CCTV Cultural Center, Shenyang HuangChao Wanxin Hotel and so on.However, the fire problem of building structure is becoming more and more serious. After buildings suffer from fire and other high temperatures, a series of physical and chemical changes will occur in concrete structure, which will result in the deterioration of structural performance to varying degrees.Especially high-strength concrete burst at high temperature, sudden and destructive, aggravated the damage of the structure.For engineering structures that use high-strength concrete materials such as the CCTV Cultural Center, they sometimes suffer from fires or other high-temperature processes, and sometimes from repeated loads such as earthquakes.At present, it is not available to estimate the residual seismic capacity or fatigue resistance of concrete structure in site engineering, which leads to the final evaluation conclusion and hidden danger of reinforcement scheme.Therefore, it is necessary to study the changes of macroscopic mechanical properties and fatigue damage of high strength concrete after different high temperature history.In this paper, the performance changes of high strength concrete (mainly fatigue properties) after different high temperature processes are analyzed by comprehensive means such as box resistance furnace, electro-hydraulic servo universal testing machine, electro-hydraulic servo fatigue testing machine and so on.The relationship between high temperature history and mechanical properties of high strength concrete is established.Through the compressive strength test and fatigue test of high strength concrete with high temperature, the relationship model between high temperature history and fatigue damage of high strength concrete is established, and the high temperature history of high strength concrete material is formed.A scientific method for the relationship between mechanical properties and fatigue damage.The mechanical properties and fatigue damage of C60 high strength concrete after different high temperature processes are studied, including residual strength, mass, elastic modulus, peak strain, fatigue life and total fatigue strain of high strength concrete.Residual strain, fatigue damage, etc.Then the temperature history and the mechanical properties of high strength concrete are studied. Compared with ordinary concrete, the mechanical properties of high strength concrete after different high temperature process are larger, and its characteristics are obviously different from ordinary concrete in the range of 500 鈩，

本文编号：1773450