高温中纤维纳米混凝土劈拉性能试验研究  

Experimental Study on the Splitting Tensile Properties of Fiber and Nanosized Materials Reinforced Concrete at High Temperature

作　　者：赵亮平 汤寄予[2] 陈刚 袁健松 ZHAO Liangping;TANG Jiyu;CHEN Gang;YUAN Jiansong(School of Civil Engineering,Henan University of Engineering,Zhengzhou 451191,China;School of Civil Engineering,Zhengzhou University,Zhengzhou 450001,China)

机构地区：[1]河南工程学院土木工程学院,河南郑州451191 [2]郑州大学土木工程学院,河南郑州450001

出　　处：《华北水利水电大学学报（自然科学版）》2023年第5期94-100,108,共8页Journal of North China University of Water Resources and Electric Power：Natural Science Edition

基　　金：国家自然科学基金项目(51908196,51809085);河南省科技攻关项目(202102310245,202102310254)。

摘　　要：随着我国城市建设规模的不断扩大,高层建筑更加密集,建筑火灾问题日益突出。为进一步探讨纤维纳米混凝土这一新型建筑材料的高温性能,通过高温中劈拉试验,研究了温度、钢纤维体积率和纳米二氧化硅掺量对纤维纳米混凝土高温中劈拉性能的影响。采用扫描电子显微镜进行微观结构观测,探讨了纳米二氧化硅对混凝土强度的增强机理和纤维纳米混凝土的高温劣化机理。结果表明:在常温至800℃条件下,随着温度的升高,纤维纳米混凝土的劈拉强度和韧性显著降低,峰值变形明显增大,这主要是由混凝土水化产物和骨料受热分解及界面黏结性能减弱造成的;当钢纤维体积率小于1.5%时,随着钢纤维体积率的增大,高温中纤维纳米混凝土劈拉强度和韧性不断提高,但其增幅小于常温时的,当温度达到600℃后,钢纤维由拔出破坏变为拉断破坏;纳米二氧化硅掺量为0.0%~1.5%时,随着纳米二氧化硅掺量的增加,高温中纤维纳米混凝土的劈拉强度和韧性均呈增大的趋势,强度增幅与常温时的接近,韧性增幅小于常温时的;纳米二氧化硅促进了水化物的生成,改善了钢纤维和骨料与基体之间的黏结性能,从而提升了混凝土的劈拉强度。With the continuous expansion of urban construction in China and the increasing density of high-rise buildings,the fire problem of building structures is becoming increasingly prominent.In order to further explore the high-temperature performance of fiber and nanosized material reinforced concrete(FNMRC),a new type of building material,the effects of temperature,steel fiber volume fraction,and nano silica content on the high-temperature splitting tensile performance of FNMRC were studied through high-temperature splitting tensile tests.The microstructure was observed by scanning electron microscope(SEM),and the strengthening mechanism of nano silica and the high-temperature degradation mechanism of FNMRC were discussed.The results are as follows.In the temperature range from room temperature to 800℃,as the temperature increases,the splitting tensile strength and toughness of FNMRC significantly decrease,while the peak deformation significantly increases.The main reason is the thermal decomposition of hydrates and aggregates,as well as the weakened interfacial bonding performance.Under 1.5%steel fiber volume fraction,with the increasing of the steel fiber volume fraction,the splitting tensile strength and toughness of FNMRC at high temperature gradually increased,while the increase is lower than that at room temperature.After the temperature reaches 600℃,the steel fiber undergoes a transition from pull-out failure to tensile failure.The content of nano silica ranges from 0.0%to 1.5%,and with the increase of nano silica content,the splitting tensile strength and toughness of FNMRC at high temperatures show an increasing trend.The increase in strength is similar to room temperature,but the increase in toughness is lower than that at room temperature.The nano silica promotes the generation of hydrates and improves the bonding performance between steel fibers and aggregates and the matrix,resulting the increase of the concrete splitting tensile strength.

关 键 词：纤维混凝土 纳米材料 高温 劈拉性能 

分 类 号：TU528.572[建筑科学—建筑技术科学]