Deicer-Scaling Resistance of Air Entraining Concrete with Different Strength

摘要

Deicer-scaling resistance of concrete subjected to the action of 4%CaCl2 solution and 5%Na2SO4 solution were investigated as well as permeability of chloride ion. A slow freeze-thawing method which simulates action of deicer salts was used in this paper: upper surface of concrete is covered by a layer of salt solution about 5mm depth and one cycle per day. The results show that deicer-scaling of concrete subjected to freeze-thawing cycles is severe in CaCl2 solution and light in Na2SO4 solution. Entraining air into concrete can improve the concrete durability subject to freeze-thawing cycles in CaCl2 solution obviously, but reduce compressive strength and resistance to chloride ion permeability when the air content of concrete increases. Concrete can have higher compressive strength and good deicer-scaling resistance when air is entrained into concrete properly, and the optimal air content of high strength concrete is about 4% but no more 5%, however, the air content should be more than 5% for the low strength concrete which has a good deicer-scaling resistance.