聚羧酸系和萘系减水剂对钢筋腐蚀影响的对比研究

A Comparative Study of Effectiveness of Polycarboxylic and Naphthalene Superplasticizer on Corrosion of Rebar Steel

用电化学方法研究聚羧酸系和萘系减水剂对模拟混凝土孔隙液中钢筋和混凝土试样中钢筋腐蚀行为的影响.结果表明,两种减水剂对模拟孔隙液中钢筋的腐蚀基本没有明显的抑制作用,但适量的减水剂可以提高混凝土的致密性,从而抑制钢筋腐蚀.通过对浸泡在2.5 mol/L NaCl溶液中的混凝土试样进行比较得知,0.1%～0.3%的聚羧酸系减水剂对混凝土中钢筋腐蚀的抑制作用大于0.2%含量的萘系减水剂,并对其抑制机理进行了初步探讨.

The effect of polycarboxylic and naphthalene superplasticizer on the corrosion behavior of rebar steel in simulated concrete pore solutions and concrete was studied by electrochemical techniques. The results indicated that two kinds of water reducer have little effect on the corrosion inhibition of rebar steel in the simulated concrete pore solutions. However, the decrease of corrosion rate of the rebar within reinforced concrete may be resulted from the decrease of porosity and the increase of density of the concrete due to the addition of proper amount of water reducer. It was found that the addition of polycarboxylic type water-reducer in a range of 0.1% to 0.3% was more effective than that of 0.2% naphthalene water reducer in reducing the corrosion rate of reinforcing steels within reinforced concrete immersed in 2.5 mol/L sodium chloride solution. The mechanism of this phenomenon was preliminarily discussed.