A Study On The Concret Slab Crack Resistance Of Pumped Storage Power Station In Clod Region

The concrete face rockfill dam is a dam type in which the upstream dam table is set up with a concrete panel as a seepage resistant material and a rockfill body as a supporting material.At present,the concrete face slab of rockfill dam is mainly controlled by strength,considering the safety and practicability of the dam structure under load.However,little consideration is given to the deterioration of material structure safety and applicability due to the long-term effects of environmental factors.China's northeast cold region has been built or under construction engineering practice shows that by the northeastern region of special climate,hydrogeological conditions,construction and other factors of interference,concrete panels in the operation period,especially during the construction period prone to deterioration of concrete performance,corrosion problems,Mainly including early and late concrete cracking,steel corrosion,concrete freeze-thaw,dissolution,environmental chemical erosion,alkali aggregate reaction failure.Among the many problems mentioned above,concrete panel cracks are one of the most important factors in reducing the durability and safety of concrete.It determines the permeability of concrete,and cracks are coupled with other problems,so that the deterioration of concrete panel performance accelerated and accelerated damage.Therefore,how to improve the durability and safety of concrete panel rockfill dam and avoid the crack of concrete face slab is one of the important problems that need to be solved urgently.There are many causes of concrete slab cracks,such as concrete raw materials,their own factors,structural factors,construction factors,natural conditions and so on.According to the relevant literature,it is learned that the concrete block cracking is mainly from optimizing the concrete mix ratio,strengthening the construction quality management of the panel,rationally dividing the joints and reinforcement,optimizing the division of the main rockfill and the downstream rock-fill to improve the compaction of the rock-fill density and other aspects of the conduct.In view of this,according to the Heilongjiang Mudanjiang region climate,geography,hydrology,geological conditions,considering the concrete panel temperature and dry shrinkage under the conditions of sensitivity.Starting from the angle of concrete raw materials,optimization of concrete mix ratio deeply,make concrete with low shrinkage and autogenous volume deformation,and adopt surface spraying technology to protect the concrete panel appearance,as far as possible to avoid the cracking of concrete panel,which is a practical concrete panel cracking technology.Through the study of this project,it can minimize the impact of concrete raw material factors on the cracking of concrete panels,and provide technical guarantee for the optimization design and site construction of concrete panels.The main contents and achievements are as follows:?1?Study on mix proportion design of cement concrete for plate crack resistanceBased on the particle size analysis of cement,fly ash and silica fume,combined with the close accumulation theory,a high performance cement based material was calculated.When the maximum density of the mixing system reaches 95.83%,the best ratio of high performance cementitious materials is 80%of cement,15%of fly ash and5%of silica fume.?2?Based on the cement-based materials mix design and the experimental research on the related properties,the optimum combination dosage of multi component composite multifunctional shrinkage reducing crack micro expansion cementitious material was determinedl:cement 74.7%,fly ash 15%,micro silica powder 5%,expansion agent 5.3%,0.6kg/m³ polypropylene fiber.?3?Study on mix proportion design and performance of anti cracking micro expansion panel concreteAfter cementing material close packing theory analysis and test,the performance of mortar?mechanical properties,deformation properties and microscopic properties?,the deployment and performance of concrete?fresh properties,mechanical properties,deformation properties,frost resistance,impermeability,anti corrosion properties and microstructure analysis of the test,etc?are recommended the multi-component micro expansion mix to meet the design requirements of C40F400W10 face concrete crack resistance.