Study On Durability Of Panel Concrete Considerring The Influence Of Ultraviolet Radiation In Alpine Area

With the further development of the concrete face rockfill dam,the durability of the concrete slab has been paid more and more attention by the engineering circles. The research show that the durability of face concrete in cold region is mainly affected by freeze-thaw cycle,while the ultraviolet radiation in high altitude is another impotant factor that affects the durability of concrete. At present. the research on the influence of ultraviolet radiation on the durability of concrete slab is still at the initial stage in the engineering field, and the limited research has not considered the joint action of freeze-thaw cycles and ultraviolet radiation.Therefore, it is very necessary to study the mechanism of the influence of ultraviolet radiation on the durability of face concrete on the basis of the interaction between freeze-haw cycle and ultraviolet radiation.This paper focuses on the following research work:(1) Based on the results of previous studies, this paper systematically analyzes the influence mechanism of ultraviolet radiation and freeze-thaw cycles on the durability of face concrete. Then, according to three kinds of samples with different water cement ratios.ultraviolet radiation test at differenl ages, and set the spec,imen without ultraviolet radiation as the control group, measuring the compressive strength of concrete and the dynamic modulus of elasticity on the same conditions of lest lime of radiation and total curing time. The test results show that: 1) The water cement ratio is smaller. the compressive strength of concrete is higher.2) Ultraviolel radiation effects on the compressive strengih of early age concrete is more obvious than the old concrete, compressive strength of high strength concrete of low strength concrete is more obvious. 3) Ultraviolet radiation can make concrete’s relative dynamic elastic modulus decreases slightly,and the ultraviolet radiation for early age concrete relative dynamic clastic modulus effect is more remarkable.(2) Based on ultraviolet radiation test for the three kinds of different water cement ratio of concrete panel, still set control group which without ultraviolet radiation, under the condition that the radiation time of each specimen was the same, the freeze-thaw cycle test was carried out for each group, test the quality and dynamic elastic modulus of the specimens after a certain number of freeze-thaw cycles, the flexural strength of the specimens was determined after the freeze-thaw cycle test. The test results show that: 1) In a certain number of freeze-thaw cycles,the greater the water cement ratio, the mass loss rate increases, and the relative dynamic elastic modulus is higher, the frost resistance of concrete is better. 2) Compared to the control group,after UV irradiation of the specimen after a certain number of cycles of freezing and thawing,the mass loss rate is greater. 3) The effect of ultraviolet radiation on the mass loss rate of low strength concrete is mainly manifested in the early stage of freeze-thaw cycle, but high strength concrete is only in the later stage of freeze-thaw cycle. 4) UV radiation has no obvious effect on the flexural performance of concrete after freeze-thaw cycles. Under the same conditions, the lower the water cement ratio is, the higher the flexural strength of concrete is.(3) According to the experimental results, this paper through the fitting analysis,considering the UV radiation freeze-thaw damage model, the results show that the freeze-thaw damage model can well reflect the evolution of freeze-thaw damage of concrete slab subjected to ultraviolet radiation.The research content and research results of this paper have some reference for the future research and it can provide reference for practical engineering.