改性钢纤维混凝土界面伸缩缝过渡区域粘接性能分析

Analysis on bonding performance of modified steel fiber reinforced concrete interface expansion joint in transition region expansion joint

以碳纤维、纳米二氧化硅及再生粗集料作为主要原料制作钢筋混凝土试件,从工作状态下的基层受力模式、粘接层厚度和钢纤维埋置深度对该区域粘接性能展开分析。试验分析表明,埋入深度为25 mm的试件,其拔出后的区域内纤维絮状物质密度最小,降低界面伸缩缝过渡区基层粘接性能;拉拔整个过程分为弹性期和软化期,弹性期位移量是由于钢质和钢质之间的内聚力决定;软化期在每一次裂纹后,基体产生局部应力消失;在钢纤维混凝土中,当粘接层厚度为75μm时,最大应力为73 N,提高了钢纤维混凝土的抗拉强度和与基体之间的粘接效果;在钢纤维的长度为5~25 mm的范围内,其长度越长,对抵御混凝土裂变的作用越好。

Carbon fiber,nano silica,and recycled coarse aggregate were used as the main raw materials to produce reinforced concrete specimens,combined with the base material of the interface expansion joint transition zone,and the bonding properties of the base layer under working conditions,the thickness of the bonding layer and the embed⁃ding depth of the steel fiber were analyzed..The experimental analysis showed that the specimen buried at a depth of 25mm had the smallest density of fibrous flocculent matter in the area after extraction,which reduced the bonding performance of the base layer in the transition zone of the interface expansion joint.The entire process of drawing was divided into an elastic period and a softening period,and the displacement during the elastic period was determined by the cohesive force between the steel and the steel.During the softening period,after each crack,local stress in the matrix disappeared.In steel fiber reinforced concrete,when the thickness of the bonding layer was 75μm,the maxi⁃mum stress was 73 N,which improved the tensile strength of steel fiber reinforced concrete and the bonding effect with the matrix.In the range of the length of the steel fiber was 5~25 mm,the longer its length,the better the effect on resisting concrete fission.