Study On The Performance Of Self-compacting Concrete And Engineering Applications In CA20 Large Modules

The rapid development of the nuclear power industry can bring huge energy supplements to the national economy.The development and application of nuclear energy as a green clean energy has become the focus of worldwide attention.The current nuclear power construction method has reached the level,which firstly the integrated prefabrication of large-scale module in the factory and then the rapid installation with large cranes on site.Modular construction can minimize the construction period,however,large-scale modules have strict safety and seismic grade requirements in design,and its large size and complex special internal and external structures make it difficult to meet the design requirements for ordinary concrete pouring inside the module.To solve this construction problem,high-performance new concrete is needed to replace ordinary concrete,which leads to the research and application of self-compacting concrete.Since there is no precedent for the construction of self-compacting concrete applied to the third-generation advanced pressurized water reactor technology AP1000 nuclear power,it is important and has engineering significance to study the performance of self-compacting concrete and the application feasibility in large-scale modules pouring.This paper has carried on the experimental research to the mix ratio and the performance of the self-compacting concrete,has optimized the pouring construction process according to the simulation experiment result,and has carried on the engineering practical application in the super large-scale structural module CA20 construction of a nuclear power plant.The main research contents of the paper are as follows:According to the properties of self-compacting concrete raw materials(including sand,stone,fly ash,cement,water reducer,air entraining agent,etc.),three kinds of mix ratio design methods(fixed sandstone volume method,improved total algorithm method and parameter method)are used to design the properties of self-compacting concrete.Through concrete mixing experiment with different raw material contents,the formula was verified and compared by testing,and then the optimal formula was selected.The influence of sand content and slurry content on the performance of self-compacting concrete was also studied.Through the one-to-one simulation experiment,the slump expansion of self-compacting concrete obtained from the selected proportioning formula was tested,and the results show that the self-compacting concrete meets the slump expansion requirements.Based on the structural features of super-large structure module CA20,the necessity of applying self-compacting concrete was analyzed.The pouring method and process were studied through engineering simulation experiments.The process of self-compacting concrete perfusion was controlled by cyclic casting to meet the requirements of concrete curing parameters as well as and the control for whole process module anti-deformation.This paper carried out four times solid self-compacting concrete pouring for CA20.The first three times were based on sufficient simulation experiments to further verify the actual engineering practice,and the fourth was the final pouring.Anti-deformation control experiments have verified the feasibility of the cyclic continuous pouring principle applied to the pouring of large modules such as CA20 with complex structures and special requirements.The results of the engineering verification experiments show that the nuclear power plant can control the quality of self-compacting concrete pouring for CA20.The optimized proportioning formula and the perfusion process can be widely used in other similar projects of nuclear power plants to create more value.