| In bridge engineering,the application of high performance concrete is more extensive,and its durability problem has become more and more important.Air-entraining agent is one of the admixtures of concrete,which has a great effect on improving the performance of concrete.Based on the engineering practice of Yingshou Bridge,Combining concrete related theory,this paper systematically studies the construction of air-entrained concrete bridges and winter anti-corrosion measures from the aspects of mix design,performance and durability of air-entrained concrete and quality control.The article first introduces the engineering geological overview of Yingshou Bridge and analyzes the applicability of the air entraining agent for Yingshou Bridge.Three kinds of strength cement concrete were used for the test.Then,the composition materials of the air-entrained concrete and the influencing factors were analyzed.Finally,the water-to-binder ratio,water consumption,cement content and sandstone amount were calculated by the strength formula to determine the reference mix ratio.The physical properties and durability of three different strength(C35,C40,C50)cement concrete were tested.The compressive strength test was carried out by using a pressure tester to obtain the compressive strength of the concrete.The slump was measured by the slumping cylinder.The bleeding rate of the concrete mixture was tested to obtain the bleeding rate.All the tests were verified to meet the requirements of the specification.After that,the characteristic parameters of the concrete bubble are measured to verify the effect of the air entraining agent.Freeze resistance refers to the ability of concrete to withstand multiple freeze-thaw cycles without being destroyed under water saturation.It indirectly reflects the ability of concrete to resist the invasion of ambient water and ice crystal pressure.Therefore,Frost resistance is often used as a concrete durability indicator.In addition,the permeability of concrete to chloride ions is also one of the key indicators of concrete durability.The chloride ion permeability of concrete directly affects the service life of concrete.Therefore,using antifreeze and chloride ion permeability as durability evaluation indexes,three kinds of concrete of different strength were tested.The results show that the antifreeze level of all three kinds of concrete is greater than F300,and the anti-chloride ion permeability coefficient also satisfies the requirements.This paper expounds the construction procedures and technological process of the air-fed concrete T-beam bridge,and analyzes its construction technology,completion and testing according to the three aspects of the foundation,pier and superstructure of the air-fed concrete bridge of Yingshou Bridge.It was found that there will be more bubbles on the surface of masonry during the construction process,which will affect the durability of the use of the Yingshou Bridge.After the determination of various test indicators,It is determined that the construction quality of Yingshou Bridge is controlled by the parameters of gas content test,freeze-resistance,chloride ion permeability and surface quality.In view of the structural durability of the Yingshou Bridge,it has been found through fieldinvestigation that the deicing salt has a great effect on the concrete,and it has a great influence on the durability of the bridge.Therefore,the deicing salt is applied to the aerated concrete from the perspective of physics and chemistry.The mechanism of the bridge is proposed,and the method of impregnating silane is adopted to prevent salt corrosion in water.The specific quality inspection and construction process are introduced according to Yingshou Bridge.After investigation,it was found that the impregnated silane method can prevent the salt corrosion of the air-entrained concrete of Yingshou Bridge.It also proves the feasibility of applying silane impregnation and anti-corrosion method to concrete bridges in cold regions. |
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