矿渣聚丙烯纤维混凝土抗弯疲劳性能  

Flexural fatigue performance of polypropylene fiber reinforced concrete containing slag

作　　者：张慧莉[1] 田堪良[1] 

机构地区：[1]西北农林科技大学水利与建筑工程学院,陕西杨凌712100

出　　处：《浙江大学学报（工学版）》2011年第4期699-707,共9页Journal of Zhejiang University：Engineering Science

基　　金：国家科技支撑计划资助项目(2006BAD11B03);陕西省自然科学基金资助项目(SJ08E111);2007西北农林科技大学归国人才基金资助项目(011404)

摘　　要：为了研究聚丙烯纤维和磨细粒化高炉矿渣(GGBFS)在不同应力水平和频率下对混凝土抗弯疲劳性能的影响,将4个配比的聚丙烯纤维和5个配比的矿渣分别掺入混凝土中,当应力水平为0.49、0.59、0.69,频率为20Hz时以及应力水平为0.59,频率为30、40、50、60Hz时测试抗弯疲劳极限强度和疲劳寿命.研究表明:累积抗弯疲劳强度能够更准确地评价混凝土抗弯疲劳性能;聚丙烯纤维可以提高混凝土累积抗弯疲劳强度和抗疲劳寿命;矿渣及其水化物使得混凝土结构密实,改善了界面过渡区(ITZ)的结构,可以提高混凝土抗弯疲劳性能;抗弯疲劳性能随着应力水平提高而下降,S-N数学模型可以用于预测20Hz频率动疲劳荷载下的矿渣聚丙烯纤维混凝土工程寿命;在一定的应力水平下,测试频率越高,抗弯疲劳性能越差,f-N数学模型可以用于预测变频率动疲劳荷载下的矿渣聚丙烯纤维混凝土工程寿命.The effect of polypropylene fiber and ground granulated blast furnace slag （GGBFS） on the flexural fatigue performance in concrete was analyzed at different stress levels and different frequencies. Four polypropylene fibers＇ volume fractions were considered. Slag was used as a replacement by weight of cement with five design proportions. An experimental investigation was conducted to obtain the fatigue lives of concrete at 0. 49,0. 59,0. 69 stress levels in 20 Hz frequency and at a constant stress level of 0.59 in 30,40,50,60 Hz frequency respectively. Results show that flexural fatigue cumulative strength is more accurate to evaluate the concrete flexural fatigue performance; the incorporation of polypropylene fiber improves flexural fatigue cumulative strength and fatigue life span; slag particles and its hydrated products benefit the density of concrete microstructure, which improves interface transition zone （ITZ） structure and benefits flexural fatigue performance. Fatigue properties decreased as the stress level increasing, and the S-N models can be used to predict the engineering life span of polypropylene fiber concrete under the dynamic fatigue load of 20 Hz frequency. At a constant stress leve, the higher the frequency, the flexural fatigue performance is poor; the f-N models can be used to predict concrete life span at different frequency.

关 键 词：抗弯疲劳极限 疲劳寿命模型 聚丙烯纤维 磨细粒化高炉矿渣(GGBFS) 扫描电子显微镜(SEM) 应力水平 

分 类 号：TU528.01[建筑科学—建筑技术科学]