Analytical Study Of Temperature Field And Temperature Stress Of Concrete Structure Under Freezing And Thawing Environment

Concrete under freezing and thawing environment suffers from cyclical temperature stress because of the change of temperature distribution, the temperature stress will damage the concrete internal structure and will effect its normal use, finally, will lead to the deterioration of bearing capacity of structural members, even hazard the safety of whole structure. Therefore, the research on temperature field and temperature stress of concrete structure under freezing and thawing environment has vital actual value.This dissertation based upon the research findings of the concrete temperature field and concrete temperature stress, comprehensively considered the process of heat transmission caused by freezing and thawing action, researched the change rule of temperature field and temperature stress of concrete structure and reinforced concrete structure under freezing and thawing cycles through both ways of measurement in laboratory and finite element analysis, improved the damage mechanics of freezing and thawing from the role of heat transfer procedure, gave the damage criterion of freezing and thawing cycles to predicate whether concrete cracks through comparing the principal tensile stress with concrete tensile strength.In the experiment cylinder concrete specimens of three different durability grades were designed which were used to measure temperature change rule during freezing and thawing cycles under two state of no water and water-saturated. The temperature of the testing point of every group of specimens under freezing and thawing action was measured through the built-in electric thermo-couple in specimens, and the effect of different concrete temperature distribution due to the different durability grades and the temperature change rule of different testing point in the same specimen in the procedure of freezing and thawing cycles were obtained. Further, we found that the degradation of concrete thermodynamic property because of its inner damage occurring with the increasing of the freezing and thawing cycle results in the change of temperature distribution under freezing and thawing action. In order to promote the research to reinforced concrete structure this dissertation also researched the problem of...