Frost Resistence Of Reinforced Concrete Beam

The frost resistance of concrete has become the unignorable factor in durabilityproblems of concrete. Studies on the effects of freeze-thaw cycles on the properties ofconcrete materials have made great progress in recent years. However, few studies on thefrost resistance properties of concrete structures or members were made. This articlefocused on the frost resistance properties of concrete beams and did following research.1) Based on the fast freeze-thaw test, the deterioration laws of axial compressivestrength and static elastic modulus were studied;2) The axial compressive strength andstatic elastic modulus decreased,making the bearing capacity of concrete and mid-spandeflection changed.;3) Analyze tensile area and compression area of the beam underfreeze-thaw cycles and effects of decrease of freeze-thaw deterioration with depth ondeflection of concrete simple supported beams and reinforcement stress were studied byfinite element methodAccording to the research results, the axial compressive strength and static elasticmodulus decreased linearly under the condition of freeze-thaw cycles. Through theregression analysis of experimental data the relationships of axial compressive strength,static elastic modulus and times of freeze-thaw cycles were given.The axial compressive strength and static elastic modulus decreased under thecondition of freeze-thaw cycles, so the bearing capacity of concrete beams declined andmid-span deflection increased. Even may lead structure to reach bearing capacity limit stateor normal use limit state. Hereby, this way can determine the concrete freez-thaw cycle life.The deflection and reinforcement stress of concrete beams increased under thecondition of freeze-thaw cycles. However, the increase of deflection and reinforcement ofthe beam in compression area is larger than that in tensile area.