The Design Method Of Frost Resistance For Concrete Structure

In cold areas, concrete structures often are damaged because of freeze-thawing cycles. In the world ,the safety of concrete structures has been assured though standards in their serviceable life.In applicable codes and standards, however there is no connection between freeze-thawing cycles of quick freezing method and the structures'in cities.In the paper, it is investigated that different freezing temperature on the damage degree of concrete. The results showed that: amount of spalling increased with the raising water-cement ratio; it increased with the lower temperature in the same water-cement ratio.And the lower freezing temperature, the more badly frost damage of concrete produced. Secondly, the amount(-15℃) is twice that when the temperature is -10℃and roughly 6 times when -5℃.Based on the results and reference, "the effective freeze-thawing cycles," and"equivalent freeze-thawing cycles" were given. The paper proposes the statistical method of the freeze-thawing cycles for different cities. Besides,it proposes the design method of frost resistance for concrete structure.Specific to the concrete structures of the typical cities in China, this paper puts fowad a method to the concrete frost resistance durability designation on the basis of the code for durability design of concrete structures(GB/T50476-2008) and'equivalent freeze-thawing cycles'. This method makes it possible to design and test a concret structure by durability service life.