通过制作专门的掺盐混凝土试件获取腐蚀钢绞线试样,然后通过静力拉伸试验研究了腐蚀钢绞线的受拉性能退化特征.结果表明:含氯盐混凝土中钢绞线具有典型的坑蚀形态特征;坑蚀引起钢绞线钢丝脆性断口的比例增大;由于坑蚀钢绞线中各钢丝的蚀坑形状、尺寸以及分布不同,使得其在静力拉伸时出现了各钢丝不同步断裂的现象;受蚀坑应力集中效应及截面削弱效应的影响,钢绞线的最大承拉力和极限平均应变出现了显著降低:在0-0.85%的腐蚀率水平下,前者约降低了9%-23%,后者约降低了50%-80%;但在上述腐蚀率水平下,钢绞线的名义弹性模量未出现明显降低.
The specimens of corroded steel strands were prepared through prestressed concrete members mixed with salt. With these specimens, the deterioration of tensile behavior was studied by tension tests. The results show that the typical pitting occurs on the steel strands in salt-contaminating concrete, and the proportion of brittle fractures increases due to the pitting corrosion. Due to the difference of pitting shape, pitting size and pitting distribution, the rupture of wires in the strand are asynchronous under static tension. Because of the stress concentration and cross section reduction caused by pitting, the ultimate tensile strength and ultimate mean strain of steel strands decline remarkably. At the corrosion ratio of 0 to 0. 85%, the ultimate tensile capacity declines by 9% to 23%, and the ultimate mean strain declines by 50% to 80%. However the nominal elastic modulus does not decrease remarkably at above values of the corrosion ratio.