Research On Mechanical Properties And Durability Of Geopolymer Concrete Application In Poles

With the development of science and technology and the progress of society,the demand for electricity in production and life is increasing,and the demand for power supply quality is also increasing.However,the climatic and working conditions faced by the power grid in the operation process are too complex,which makes it difficult for traditional concrete poles to meet the corresponding structural and functional requirements.With the in-depth research on geopolymer materials,it is found that geopolymer concrete has excellent properties such as high strength,early strength and corrosion resistance.However,due to the lack of perfect preparation specifications and insufficient research,it has not been widely promoted.To solve the problem that the power system has increasing requirements for towers,a metakaolin-based polymer concrete with excellent mechanical properties was prepared and applied to the design of conical poles.The main research contents and results are as follows:(1)Through the orthogonal test and slump optimization test,the optimal mix ratio was determined as 3.5 bone cement ratio,40%sand ratio,1.25 solid-liquid ratio.Through formula derivation and parameter analysis,the stress-strain curve equations of geopolymer concrete at different ages were constructed based on the concrete constitutive model proposed by Guo Zhenhai,and the fitting results were consistent with the test results.(2)Carbon fiber(0.1%,0.2%,0.3%)and steel fiber(1%,2%,3%)were mixed into geopolymer concrete,respectively.The effects of different fiber types and dosage on the basic mechanical properties and impact resistance of geopolymer concrete were studied,and the action mechanism of fiber was revealed.The results show that under the action of fiber crack resistance mechanism,the performance of steel fiber with 2%volume content is the best.At this time,the compressive strength,split tensile strength,flexural strength and impact toughness are 76.27MPa,11.92MPa,9.405MPa and 7133.83N m.(3)The effects of three different admixtures,VAE,APAM,and CPAM on the dry shrinkage properties of geopolymer mortar under normal temperature curing conditions were explored.The results show that under the effect of strengthening and toughening the mortar by the reaction of VAE to form a polymer film,4%VAE admixture can significantly improve the dry shrinkage of geopolymer mortar.Due to its film-forming properties,PAM can hinder the movement of water molecules,thereby improving its dry shrinkage.2.5%APAM admixture and 1.5%CPAM admixture can improve the dry shrinkage performance of geopolymer mortar within a certain range.(4)Based on the optimal ratio and the optimal fiber type and dosage,the geopolymer concrete with or without fiber(2%steel fiber)under three different alkali activator modulus of 1.3,1.5,and 1.8 was designed in different freeze-thaw cycles.The frost resistance(surface damage,mass loss rate and relative dynamic elastic modulus loss rate)under the number of times and the damage and deterioration model of geopolymer concrete was established.The results show that:under the influence of water glass modulus and fiber,the frost resistance of geopolymer concrete is 1.3M>1.5M>control group>1.7M,with fiber>without fiber in descending order.