Response Relationship Between The Micro Environment And The External Environment Of Recycled Concrete

Not only natural aggregate is saved,but also the environmental pollution caused by waste concrete is reduced due to the research and application of recycled concrete and it is of great significance to the sustainable development and environmental protection and energy saving.Concrete response relationship between the internal micro environment and the external environment has important influence on the durability deterioration process and service life in the research of the normal concret.To ensure that the recycled concrete structure durability life,response relationship of recycled concrete between internal environment and micro environment is necessarily studied.Recycled concrete pore water saturation,thermal conductivity,laws of surface wetness positive diffusion and influence of micro environment on the corrosion of steel bar in recycled concrete were studied by the method of recycled coarse aggregate instead of natural coarse aggregate.In this paper, the main research work and research results are:(1)The influence rules of pore water saturation in concrete recycled under artificial climate environment was studied.Weight change of recycled concrete under the test conditions was mainly measured for the value of pore water saturation.The influence rules about the temperature,water cement ratio,recycled coarse aggregate replacement ratio and relative humidity of recycled concrete pore water saturation were obtained and the prediction model of recycled concrete pore water saturation within the range of certain conditions was fitted.(2)The influence rules of the thermal properties of recycled concrete was studied.The thermal conductivity of recycled concrete under different pore water saturation conditions was measured and influence rules of the thermal conductivity about water cement ratio, pore water saturation and recycled coarse aggregate replacement ratio were obtained and the prediction model of the recycled concrete thermal conductivity within the range of certain conditions was fitted.(3)The influence rules on positive humidity diffusion coefficient of surface layer recycled concrete under artificial climate environment was studied. To analyse influence rules on the relative humidity in recycled concrete of temperature, water cement ratio and replacement ratio of coarse aggregate,change rules of relative humidity response of recycled concrete were measured under conditions of test environment. According to the test results,calculation formula of positive humidity diffusion coefficient was fitted and calculated values of positive humidity diffusion coefficient in a certain range of relative humidity were obtained.The influence of temperature,water cement ratio,the replacement ratio of recycledcoarse aggregate and relative humidity on positive humidity diffusion coefficient of surface layer recycled concrete and prediction model of positive relative humidity diffusing coefficient of the surface layer recycled concrete was fitted under certain conditions.(4)The influence rules of internal micro environment of recycled concrete on corrosion rate of steel bar were studied under artificial climate environment.Steel corrosion current density of recycled concrete were mainly measured under various test conditions and influence on the steel corrosion current density of temperature, water cement ratio, recycled coarse aggregate replacement ratio and relative humidity.