Study On Cement Mortar For Repair Used In The Environment Of Corrosion With Chloride And Sulfate

As the development of economy, the concrete buildings of our country become more and more complex. The reinforced concrete or pre-stressed concrete in the coast and cross areas, the harmful ion of the environmental caused the steel corrosion, and make the concrete protective layer bursting, causing the durability problem of marine concrete structures, it would be very troublesome to repair, or impossible to repair, so, the repair of cement concrete structures under the marine environment was extremely urgency.Based on the study to the performance of different systems of cementitious materials, the paper determined the ratio of cementitious materials, then chose suitable additives of dry mixed mortar, confected the polymer repair mortar used in the environment of sulfate and chloride.Then research the influence of the ratio of sand and lime, defoamer and redispersible powder to the basic mechanics performance of repair mortar. The results showed that: defoamer could improve the compressive strength and flexural strength of repair mortar significantly. With the increase of C/S, the compressive strength, flexural strength and bond strength were increased gradually. With the increase of the amount of redispersible powder, the bond strength of repair mortar was increased. Compared the redispersible powder at the same level, we found that: The effects of different redispersible powder on bond strength of repair mortar were b> a.Research different of kinds and amount of redispersible powder resistence the chloride ion penetration with the method of ASTM C1202,NEL and RCM, resistence sulfate and marine erosion performance, The results showed that: redispersible powder and cellulose ether can both improve the performance of resistence the chloride ion penetration of repair mortar, and improve the performance of resistence sulfate and marine erosion in short period.The mix of repair mortar: In the rich Portland cement system, when the proportion of sulphoaluminate cement, Portland cement, fly ash was respectively 8%, 77% and 15%, the amount of anhydrous gypsum and CSA Expansive Agent was 0.4% and 8% of the content of Sulphoaluminate and Portland cement, and the proportion of redispersible powder, Cellulose ether and triethanolamine was respectively 4%, 0.2% and 3%, the properties of repair mortar were the best.