几种水泥添加剂对混凝土性能影响的电化学研究

Study on effect of several additives on concrete properties by electrochemistry

应用4×4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浓度为1.9mol/L的NaCl溶液中,通过测量铁丝束电极的自腐蚀电位,获得在不同埋置深度时,铁丝腐蚀的电位分布信息;并研究了加入不同水泥添加剂对水泥性能影响的电化学行为。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0.25%木质磺酸钠,铁丝自腐蚀电位负移量减少,腐蚀程度显著下降;加入0.34%苯甲酸钠,铁丝自腐蚀电位负移量比加入木质磺酸钠更少,铁丝的腐蚀程度明显减少;当混凝土中同时添加0.25%木质磺酸钠和0.34%苯甲酸钠时,电位负移速度减缓,但达不到单独添加木质磺酸钠或苯甲酸钠时的防腐效果。比较得出,单独加入苯甲酸钠防腐效果最好。

The corrosion of rebar in concrete was studied by 4×4 liner wire - beam electrode. The corrosion potential distribution of wire - beam electrode in different depth was obtained by testing corrosion potential in 1.9 mol/L NaCl solution. The effect of different additive on cement was also studied. The results showed that the corrosion of iron wires in ordinary concrete was asymmetrical, and the corrosion potential value was scattered, and with the immersion time increased, the corrosion potential move to negative; adding 0.25% sodium lignosulphonate, the negative move of corrosion potential reduced and the corrosion of iron wires obviously lightened; adding 0.34% benzophenone, the negative move of corrosion potential and corrosion rates reduced more; adding 0.25% sodium lignosulphonate and 0.34% benzophenone together, the negative move of corrosion potential slowed down, but couldn＇ t reach the extent of that of adding the additive respectively. The result is that for corrosion prevention 0.34% benzophenone as additive was the best.