Study On The Durability Of Concrete Structures Blended With Solid Waste Under The Combined Action Of Load And Environment

With the acceleration of urbanization and infrastructure construction, concrete durability issues have been paid more and more attention. This paper relies on transportation projects:"Durability and reliability design method of marine concrete structures under load and environment coupling effects" studies concrete durability under the combined action of load and frozen salts. For loads, freeze-thaw cycles, concrete specimens under multivariate coupling sodium chloride solution, applying four different load levels, bending loads of different admixtures, axial compression load test specimens were freeze-thaw, at the same environment measure their percentage of chloride ions, combined with Fick second law. Analysis the raw of concrete durability deterioration under the combined action of load and frozen salts.And the conclusions were drawn from the above work:Bending load will accelerate the migration of chloride ion diffusion in concrete, chloride ion diffusion coefficient of concrete specimens with increased levels of bending stress increases, between chloride diffusion coefficient and the stress level is approximately exponential function as D0/Dη=A·e-Bη,At 56 days of age A=1.02, B= 1.363, durability design of concrete structures should be considered in the bending load on chloride ion diffusion coefficient.Bending loads and pressure loads will not only produce concrete aggregate and paste interfacial transition zone on crack, but also cause changes in the pore structure of the slurry, which is the root cause of the load caused by concrete chloride ion diffusion coefficient of variation.Freezing and thawing of concrete specimens from the exposed surface of the chloride ion concentration at the same depth as improve the bending stress level increases, and chloride ions in the concrete penetration depth increases with the stress level increases. Specimens from the surface after exposure to chlorine ion concentration at the same depth with increasing pressure to reduce the stress level increases, freezing and thawing, and load coupling effect will affect the concrete distribution of chloride concentration.In the bending load and freeze-thaw coupling between different levels of bending stress of concrete chloride ion diffusion coefficient was approximate exponential runction as D0/Dη=A·e-Bη, where A,B are parameters reated to the composition of the cementing material for axial compression load and coupling of freezing and thawing concrete specimens,the relationship between different levels of stress and the diffusion coefficient is ,and Dd0=k·Do,the impact of freezing and thawing of concrete specimens factor chloride ion diffusion coefficient is a parameter related to the composition and cementitious materials:without admixture k=1.72; mixed 30% of the fly ash when k=5.95；60% when mixed with slag k=1.29; complex when fly ash and slag k=1.0.