无机添加剂对混凝土性能影响的电化学研究

Study on effect of inorganic additive on concrete properties by means of electrochemistry

应用3×3阵列丝束电极模拟研究了混凝土中钢筋的腐蚀。将混凝土试样浸泡在10%NaCl溶液中,通过测量铁丝束电极的自腐蚀电位,获得了在不同埋置深度时,铁丝腐蚀的电位分布信息,研究了加入不同无机添加剂对它的影响。结果表明,普通混凝土中铁丝腐蚀不均匀,自腐蚀电位较分散,电位随时间负移。加入20%粉煤灰,铁丝自腐蚀电位负移量减少,腐蚀程度显著下降;加入4%NaNO2,铁丝自腐蚀电位负移量比加入粉煤灰更少,铁丝的腐蚀程度明显减少,但NaNO2作为阻锈剂存在局限性;当混凝土中同时添加粉煤灰和NaNO2时,电位负移速度减缓,但达不到单独添加粉煤灰或NaNO2时的防腐效果。比较得出,单独加入粉煤灰防腐效果最好。

The corrosion of rebar in concrete was studied by 3 ×3 liner wire beam electrode. The corrosion potential distribution of wire-beam electrode in different depth was obtained by estimated corrosion potential in 10% NaCl solution. The effect of different inorganic additive on him was studied. The results showed that the corrosion of iron wires in ordinary concrete was non-tmiform. The corrosion potential was scattered. With the increase of immersion time, the corrosion potential shifted negatively. With the addition of fly ash by oneself, the negative shift value of corrosion potential reduced and the corrosion of iron wires obviously reduced; With the addition of 4% NaNO2 by oneself, the negative shift value of corrosion potential and corrosion rates reduced more, but the inhibitor NaNO2 that has disadvantage; With the addition of fly ash and NaNO2 at the same time,the negative shift value of corrosion potential reduced too,but compare with other additive,the effect of anticorrosion was the worse. In a word, fly ash as additive by oneself was best for the effect of anticorrosion ofrebar in concrete.