混凝土碳化研究与进展(3)--腐蚀因子的迁移

混凝土碳化时Friedel盐和硫铝酸盐分解产生的氮离子和硫酸根离子向未碳化区迁移产生浓缩．使这两种离子在碳化区浓度显著降低，碳化前沿的浓度明显升高；同时混凝土中的钠、钾等碱金属离子。向氯离子和硫酸根离子相反方向迁移和浓缩，导致未碳化区这两种离子浓度明显升高，碳化区浓度显著降低。园此舍氮盐混凝土碳化时由于氮离子和硫元素向来碳化区迁移和浓缩，碳化未达到钢筋表面时钢筋已经开始腐蚀。

A review of carbonation in reinforced concrete( Ⅲ ): Migration of corrosive factors in concrete

The chlorides and sulfides fixed inside concrete are dissociated in the form of ions as carbonation progresses and migrate toward the interior of the concrete, an non-carbonated zone. Parts of very high concentration are formed locally. And alkali rrietal ibns also migrate and are disclosed, and parts of very high concentration are increased locally in non-carbonated zone. Based on the findings, rebar corrosion is initiated before neutralization reaches the surface of the reinforcing bars, because neutralization of concrete containing chlorides causes enrichment of chlorides, and sulfur to move toward the non-neutralized zone.