中文摘要：

针对原状碳纤维与水泥基体界面粘结差,导致水泥基复合材料韧性低等问题,采用常温硝酸、80℃硝酸水浴、80℃混酸（硝酸40%＋浓硫酸60%）水浴等3种工艺进行碳纤维表面处理,制备碳纤维增强水泥基复合材料（CFRC）;利用SANS万能试验机,测试其弯曲强度,并计算韧性指数;同时借助扫描电镜（SEM）分析处理后的碳纤维表面微观结构。研究结果表明：与含未经表面处理碳纤维CFRC相比,碳纤维经过表面处理后,CFRC的极限弯拉强度、跨中位移和韧性指数明显提高,其中经80℃混酸水浴后,其增幅分别达到42.2%、87.5%和128.8%;碳纤维表面微观结构发生变化,经80℃混酸水浴处理的碳纤维表面存在明显刻蚀痕迹,沟槽数量增加,有助于提高CFRC韧性。

英文摘要：

Regarding the problems of carbon fiber and cement matrix interface with low bonding strength,leading to poor toughness and easy taking off,this paper adopted three kinds of surface treating techniques,nitric acid treatment;80 ℃ nitric acid water bath treatment and 80 ℃ mixed acid water bath treatment,to modify carbon fiber,which were used to prepare carbon fiber reinforced cement based composites（CFRC）.The SANS facility was used to test the bending strength and calculate toughness index of CFRC.Besides,SEM was also used to analyze surface micro structure of treated cabon firber.The results indicate that bending strength,displacement and toughness index of CFRC with treated carbon fiber are all enhanced in contrast to those of CFRC with untreated carbon fiber.Especially,those of CFRC with carbon fiber with 80℃ mixed acid water bath treatment increase to 42.2%,87.5% and 128.8% respectively.The surface microstructure of carbon fiber has changed,and there are erosion phenomena and many grooveson the surface of treated carbon fiber,which are advantageous to increase toughness of CFRC.