锈蚀钢绞线的静力拉伸断裂特性

通过制作专门的掺盐预应力混凝土构件获取锈蚀钢绞线试样,借助宏观观察和微观电镜扫描手段研究了试样的静力拉伸断裂特性,分析了锈蚀对钢绞线静力拉伸断裂特性的影响问题.研究结果表明:当钢绞线钢丝锈蚀坑底部珠光体团的位向与钢丝纵轴线间的夹角较小时,会形成延性的铣刀式断口或杯锥式断口;反之,当该夹角较大时,会形成脆性的劈裂式断口或劈裂-铣刀式断口;钢绞线钢丝锈蚀坑处珠光体团的位向是一个概率问题,钢绞线的总体锈蚀程度越大,锈蚀坑与上述夹角较大珠光体团相遇的概率也越大,钢丝出现脆性断裂的概率也越大,整根钢绞线的脆性断裂特征也越明显.

Fracture behaviour of corroded steel strands under static tension

The specimens of corroded steel strands were proposed by purposemade prestressed concrete members mixed with salt.With these specimens,the fracture behavior under static tension was studied by marcro-and microscopic investingation.The influence of corrosion on the fracture behavior under static tension is also discussed.The investigation results show that firstly when the angles between the orientation of pearlites in the corrosion pits and the longitudinal axis of the wires are small,the fractures are ductile and in fraise-mode or cup-mode;whereas,when the angles are large,the fractures are brittle and in cleavage-mode or cleavage-fraise-mode.Secondly,it is a probabilistic affair of the orientation of pearlites in the corrosion pits.With more degree of corrosion,the probability of corrosion pits meeting the pearlites with large angles is more,the probability of brittle fracture of wires is more,and the brittle fracture character of steel strand is clearer.