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首页> 外文期刊>Corrosion Engineering, Science and Technology >Durability performance of rebar embedded in chloride admixed blended cement concretes
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Durability performance of rebar embedded in chloride admixed blended cement concretes

机译：氯化物掺合水泥混凝土中埋入钢筋的耐久性能。

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In concrete structures, permeation of chloride ions either through the pores or by visible/microcracks or contamination of chloride along with the fine and coarse aggregates increase the availability of chloride ion at the rebar level. The reduction of OH~- ions by pozzolanic reaction and by replacement of cement by mineral admixtures may reduce the chloride ion tolerable limit of rebar in blended cement concretes. In the present investigation, the corrosion rate of rebar in 0.5 and 1% chloride admixed concrete was assessed periodically up to a period of 1765 days using electrochemical impedance spectroscopic technique. Ordinary Portland cement (OPC), pulverised fuel ash cement (PFAC) and blast furnace slag cement (BFSC) were evaluated in 20, 30 and 40 MPa concretes. The high R_p value of rebar obtained in blended cements indicates that the additional calcium hydrates maintains the pH and also contributes significantly to the inhibitive effects at the steel/concrete interface thus maintaining the passivity of rebar. The results reveal that the high chloride ion complexing ability and microstructural changes by the formation of additional calcium hydrates in the PFAC and BFSC concrete matrix enhancing the corrosion resistance of rebar by a factor of five times than that of OPC concrete in 0% chloride added concrete and three times in 1% chloride contaminated concrete. The reduction of OH~- ions did not decrease the chloride tolerable limit of rebar in PFAC and BFSC concrete; moreover they had 1.4 times higher chloride tolerance than that of OPC concrete.
机译：在混凝土结构中，氯离子通过细孔或可见/微裂纹的渗透或氯化物的污染以及细骨料和粗骨料的渗透都会增加钢筋水平上氯离子的利用率。通过火山灰反应和用矿物掺合料替代水泥来减少OH-离子，可以降低水泥混凝土中钢筋对氯离子的耐受极限。在本研究中，使用电化学阻抗谱技术定期评估钢筋在0.5％和1％氯化物掺混混凝土中的腐蚀速率，直至1765天。在20、30和40 MPa的混凝土中评估了普通波特兰水泥（OPC），粉煤灰水泥（PFAC）和高炉矿渣水泥（BFSC）。在混合水泥中获得的钢筋的高R_p值表明，额外的水合钙保持了pH值，并且还显着地促进了钢/混凝土界面的抑制作用，从而保持了钢筋的钝化性。结果表明，PFAC和BFSC混凝土基质中形成额外的水合钙，具有较高的氯离子络合能力和微观结构变化，在添加0％氯的混凝土中，钢筋的耐蚀性比OPC混凝土高五倍。并在1％受氯污染的混凝土中进行三遍。 OH〜-离子的减少并没有降低PFAC和BFSC混凝土中钢筋的耐氯化物极限。此外，它们的耐氯性是OPC混凝土的1.4倍。

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