高温后纤维纳米混凝土单轴受压应力-应变关系  

Compressive stress-strain relationship of fiber & nanosized materials reinforced concrete after exposure to high temperature

作　　者：高丹盈[1] 李晗[2] 

机构地区：[1]郑州大学新型建材与结构研究中心,河南郑州450002 [2]郑州航空工业管理学院,河南郑州450046

出　　处：《土木工程学报》2015年第10期10-20,共11页China Civil Engineering Journal

基　　金：国家自然科学基金(51178434)

摘　　要：通过306个150mm×150mm×300mm纤维纳米混凝土棱柱体试块在25—800℃后的单轴受压试验，探讨钢纤维体积率、纳米材料掺量和高温对纤维纳米混凝土受压应力-应变曲线的影响。结果表明，纤维纳米混凝土受压应力-应变曲线可分为弹性阶段、裂缝稳定发展阶段、裂缝失稳扩展阶段和破坏阶段；随钢纤维体积率和纳米材料掺量的增大，应力-应变曲线逐渐饱满，峰值应力和峰值应变均有一定程度的提高，曲线下包面积逐渐增大；随温度升高，应力-应变曲线趋于扁平，弹性段逐渐变短，峰值应力显著降低，峰值应变增大，应力-应变曲线下包面积减小。通过对试验数据的综合分析，建立了考虑纤维、纳米材料和温度影响的纤维纳米混凝土轴压应力-应变曲线数学模型。The uniaxial compression experiments were conducted on 306 prism specimens with the size of 150mm × 150mm ×300mm for fiber and nanosized materials reinforced concrete （FNMRC） after being exposed to 25-800℃. Based on the experimental observation, the effects of steel fiber volume fraction and nanosized materials content and exposure temperature on the uniaxial compressive stress-strain curves of FNMRC were systematically analyzed. Test data indicate that the compressive stress-strain curve of FNMRC can be divided into the elastic, crack initiation, crack instability and failure stages. With the increasing of the steel fiber volume fraction and nanosized materials content, stress-strain curves gradually plump; both peak stress and strain at peak stress have a certain increase. With the increasing of exposure temperature, stress-strain curves are gradually flattened, ascending liner portions of the stress- strain curve are shortened, peak stress significantly is decreased, and strain at peak stress show a trend of increase. High temperature causes significant deterioration to the nature of the stress-strain curve. A simple analytical model is proposed to generate both the ascending and descending portions of the stress-strain curve, which considers the effect of steel fiber, nanosized materials and exposure temperature.

关 键 词：纳米材料 纤维 混凝土 高温 应力-应变关系 

分 类 号：TU528.57[建筑科学—建筑技术科学]