【作者】 李岩；

【导师】 方璟； 朱雅仙；

【作者基本信息】 南京水利科学研究院 ， 材料学， 2003， 硕士

【摘要】 本文着重研究了全浸泡条件下和干湿循环条件下，氯离子在不同水胶比和不同掺量的粉煤灰、矿渣粉混凝土中的渗透性能，以及混凝土内钢筋腐蚀的氯离子临界浓度。 通过取样测得不同技术条件混凝土各层氯离子含量，得到氯离子扩散系数与时间成幂函数关系，据此推出氯离子在混凝土中扩散的数学模型式为： 试验结果表明，氯离子的扩散系数随着水胶比的减小而降低，适当地掺入粉煤灰或矿渣粉可以有效地降低氯离子的扩散系数。氯离子在混凝土中的扩散系数还与实验条件有关，干湿循环条件下的扩散系数均大于全浸泡条件下的。 本文利用半电池电位法、交流阻抗法和时间电位法三种电化学无损检测技术判断评估试件在试验过程中钢筋腐蚀状况，当钢筋由钝化状态转为活化状态时，取样分析钢筋周围氯离子含量，得到了不同技术条件混凝土的氯离子临界浓度。结果表明，同技术条件的混凝土试件，在全浸泡条件下的氯离子临界浓度均要大于干湿循环条件下的，即临界浓度大小受到试验条件的影响；相同的试验条件下，水胶比对氯离子临界浓度大小有显著地影响，而掺入适量的粉煤灰或矿渣粉对氯离子临界浓度无明显地影响。 对氯离子临界值占胶凝材料百分比含量进行线性拟合，得到了全浸泡条件下和干湿循环条件下氯离子临界浓度随混凝土水胶比变化的关系式。 研究结果表明，利用交流阻抗谱不仅可以快速、准确的判断混凝土中的钢筋腐蚀状态，而且对工作电极的扰动小，还可得到关于混凝土和钢筋表面的诸多信息。因此，交流阻抗技术是研究混凝土内钢筋腐蚀状态的有力工具。更多还原

【Abstract】 In this paper, it was mainly studied that the penetration capacity and critical content of chloride ions in concrete with different water/binder ratio, fly ash and slag under immersion and cycle of dry and wet conditions.The relationship of chloride ions diffusion coefficient with time conforms to power function according to chloride ions’ content in each layer of different concrete. Based on the relationship, a mathematical model equation of chloride ions diffusion in concrete was deduced as follow:Test results show that chloride ions diffusion coefficient decreases with the water/binder ratio reducing. When fly ash or slag is properly blended, chloride ions diffusion coefficient will also drop. Chloride ions diffusion coefficient is related with test conditions, the diffusion coefficient in cycle of dry and wet conditions is always larger than that in immersion conditions.In this paper, rebar corrosion state was judged with three electrochemical nondestructive measuring technologies, i.e. half-cell potential, A.C. impedance and time potential. When the rebar was transformed from passivation to depassivation, it can obtain the chloride ions corrosion critical content through taking and analyzing chloride ions content around the rebar. Test results show chloride ions critical content in immersion conditions is always larger than that in cycle of dry and wet for the same concrete, that is, test conditions affects chloride ions critical content value. In the same conditions, water/binder ratio obviously affects chloride ions critical content, but the influence of fly ash or slag on chloride ions critical content is not obvious.It is obtained the equation that chloride ions critical content change with water/binder ratio through linear fitting experiment data.The studied results also show A.C. impendence spectrum not only can quicklyand exactly judge the rebar state in concrete, but also hardly disturb the work electrode, in addition, much message of the concrete and rebar surface can be obtained. Therefore, A.C. impendence technology is a promising method in studying the rebar corrosion state in concrete.更多还原