Study On Mechanical Properties And Durability Of Doped Fiber Reinforced Microporous Concrete

Since the 14 th Five Year Plan period,in the context of China’s implementation of the "dual carbon strategy" goals,consumption reduction and carbon reduction actions,and the promotion of new building industrialization,lightweight aggregate concrete itself has the characteristics of lightweight,high-strength,energy conservation,and environmental protection,and has begun to be applied in load-bearing structural buildings.This paper adopts the orthogonal experimental design method and conducts mechanical performance and durability tests to study and analyze the compressive strength,size effect,relationship between cube compressive strength and axial compressive strength,static compressive modulus of elasticity,and durability performance,including frost resistance,permeability resistance,and shrinkage performance,of ceramsite lightweight aggregate concrete for LC 35 structure.This paper first conducts experiments on the physical and mechanical properties of shale ceramsite.Based on the experimental results and orthogonal experimental mix design,it is concluded that the main influencing factors on the strength of ceramsite lightweight aggregate concrete include the water cement ratio,fly ash content,ceramsite content,and sand ratio.By using range and variance analysis,the influence of various factors on the strength of the 28 day cube compressive strength of ceramsite lightweight aggregate concrete was determined to be as follows: ceramsite content>water cement ratio>sand ratio>fly ash content,with a ceramsite content of 480 Kg,a water cement ratio of 0.36,a fly ash content of 20%,and a sand ratio of 42% as the optimal plan,and the water cement ratio,fly ash The addition of ceramic particles and the sand ratio will not have any difference in the 28 day compressive strength of ceramic lightweight aggregate concrete(LAC).Determine the optimal mix ratio: water cement ratio: 0.36,cement: 360 Kg,fly ash: 90 Kg,ceramsite: 480 Kg,sand: 775 Kg,water reducing agent: 4.5 Kg.The ceramsite lightweight aggregate concrete mixed with the best mix proportion optimized by orthogonal test design has good homogeneity.Statistical analysis of the compressive strength shows that the cube compressive strength has little variability and conforms to the normal distribution law.The trend of strength change of ceramsite lightweight aggregate concrete indicates that the early strength increases quickly,while the later strength changes slowly.Moreover,a logarithmic model can be used to predict the 28 day strength,and the relative error of the prediction results is also very low.The ratio of cube compressive strength to axial compressive strength is 0.984,which is in line with the safety of building structural design.After 150 freeze-thaw cycles,the relative dynamic elastic modulus and mass loss rate of ceramsite lightweight aggregate concrete will significantly decrease.Among them,when the freeze-thaw cycles reach 150,the relative dynamic elastic modulus of ceramsite lightweight aggregate concrete can reach 71.1%,and the mass loss rate is only 3.72%.As the strength grade of concrete increases,its impermeability will also improve,ultimately reaching P 12.The shrinkage rate of ceramsite lightweight aggregate concrete will rapidly increase in the early stage,but over time,the shrinkage rate will gradually decrease,and the FA content will also make the concrete shrinkage rate more obvious.When the curing period of ceramsite lightweight aggregate concrete reaches 60 days and the FA content reaches 20%,its shrinkage rate significantly increases,reaching 25%,and the shrinkage rate increases by 10%.