关键词: 稀硫酸;水泥砂浆;附面层效应;表观扩散系数

Abstract: A product layer will be formed on the surface of specimen during the process of the cement mortar attacked by the sulfuric acid , which will bring a blocking effect to the corrosion process and so as to decrease the reaction rate .To investigate the blocking effect , two batches of long time immersion tests of cement mortar with 2300 h were carried out .To compare and eliminate the accumulation of the product layer, one batch of the specimens were cleaned the surfaces and replaced immersion liquid periodically . The corrosion amounts at different time were recorded in term of the consumption of sulfuric acid .The apparent diffusion coefficients of mortar at different immersion time were calculated by the model of dissolution reaction and experiment datum .The changing of the apparent diffusion coefficients in different batch and at different soaking time was obtained .The result shows that the apparent diffusion coefficients observed in both batches will decrease according to the power law of immersion time because of the influence of the product layer .However , the influence of the product layer effect can be reduced by changing the soaking solution and removing the adhesive layer periodically .

Key words: sulfuric acid;cement mortar;product layer;apparent diffusion coefficient