摘要
为了研究混凝土内钢筋的锈蚀过程及其内在机理,通过对不同锈蚀阶段钢筋与混凝土界面的细观观测,描述了锈蚀层的形成与发展过程,给出了钢筋锈胀力的分布形态,揭示了混凝土锈胀开裂过程和钢筋锈蚀速率的时变过程.结果表明:钢筋锈蚀产物的膨胀性以及钢筋-混凝土界面区的多孔性,为铁锈物向界面区孔隙内的扩散提供了条件,随着锈蚀的进行,原有的界面区逐渐演变为混凝土与铁锈物混合的锈蚀层.锈蚀层的进一步发展,不仅会导致钢筋表面界面区逐渐密实,阻碍混凝土保护层中氧气和水分向锈蚀界面的输送,使混凝土内钢筋锈蚀速率下降,而且会使锈蚀物在钢筋表面产生对混凝土的膨胀力,最后导致混凝土开裂.
In order to study the expansion and mechanism of corrosion of steel bars in concrete, micro-structural observations of the interracial transition zone （ITZ） between steel bars and concrete at different corrosion stages were used to depict the generation and development of the corrosion layers. The distribution of the expansive force of corrosion of the steel bars was determined. The time-dependent change characteristics of the corrosion expansion-induced cracking process of the concrete and the corrosion rate of steel bars were obtained. The test results show that the swellability of the corrosion products of the steel bars and the porosity of the ITZ between the steel bars and the concrete enhance the diffusion of Fe oxides into the pores in the ITZ. With corrosion, the original interracial region gradually becomes the corrosion layer of the concrete mixed with the Fe oxides. Further development of the corrosion layer leads to the gradual compaction of the interracial regions on the surface of the steel bars so as to prevent the transport of air and oxygen in the concrete armored layer to the corroded ITZ, resulting in the decrease of the corrosion rate of the steel bars in the concrete. Furthermore, the corrosion products enhance the expansive force on the surface of the steel bars against the concrete, resulting in cracking of the concrete.
出处
《河海大学学报（自然科学版）》
CAS
CSCD
北大核心
2009年第4期430-436,共7页
Journal of Hohai University(Natural Sciences)
基金
国家自然科学基金(5053807050878207)
中国矿业大学校基金(OB061045)
关键词
混凝土
界面区
钢筋锈胀力
锈蚀速率
时变性
concrete
interface
expansive force of steel bars
corrosion rate
time-dependent change characteristic
