Research On Mechanical Properties Of CF120 High-toughness Hybrid Fiber Concrete Shaft Lining

With the popularization and application of ultra-high-strength concrete in the shaft wall structure,the brittleness problem becomes more and more obvious.As a new type of composite high-performance material,hybrid fiber concrete has obvious toughening and crack resistance effects.Hybrid fiber toughening and reinforcement are used in mine shafts.Wall concrete research has not yet been carried out.In this paper,CF120ultra-high-strength and high-toughness concrete suitable for vertical shaft wall was successfully prepared,and different fiber mixing methods（rows of long steel fibers-copper-plated micro-wire short steel fibers and rows of long steel fibers-polypropylene fibers were studied Hybrid）,fiber content,etc.on the physical and mechanical properties of concrete and bending toughness,to obtain the mechanical properties of hybrid fiber concrete shaft wall,the main research results are:1)Adopting conventional technology,by mixing high-performance water-reducing agent and ultra-fine active mineral admixture,selecting high-strength and high-quality aggregate,the strength of concrete is 105MPa～130MPa,strength grade is CF95～CF130,high strength,high toughness High-flow concrete provides basic technical support for the application of ultra-high-strength and high-toughness concrete in deep well engineering.2)The use of different lengths of fiber size（rows of long steel fibers-copper-plated microfilament short steel fibers hybrid）,steel fibers and flexible fibers（rows of long steel fibers-polypropylene plastic fibers hybrid）hybrid,mixed The influence of the method and its content on the workability,compressive strength,splitting tensile strength,flexural strength,and bending toughness of the concrete,and the compressive strength,splitting tensile strength,flexural strength,and bending toughness of the concrete were obtained.law.When a row of long steel fibers（35kg/m³ content）-copper-plated microfilament short steel fibers（20kg/m³ content）is combined,the bending toughness indexes I₅,I₁₀,I₂₀ are 5.12 times,7.55 times,respectively,of plain concrete.8.87 times,and increased by 31.3%,53.1%and 77.8%compared with single-row long steel fiber concrete.The blending of hybrid fibers obviously improves the brittleness of concrete,and hybrid fibers concrete with high strength and toughness with excellent properties are obtained.3)A large-scale physical simulation test of the shaft wall was carried out,and the deformation behaviors of two types of shaft walls,such as rows of long steel fiber-copper-plated microfilament short steel fiber concrete and rows of long steel fiber concrete were studied,and hybrid fibers were obtained.Mechanical properties of ultra-high-strength concrete shaft wall.The research results of this paper lay a theoretical foundation for improving the toughness of ultra-high-strength concrete shaft wall and promoting the application and development of ultra-high-strength and high-toughness hybrid fiber concrete in mine shaft wall.The paper has 77 pictures,30 tables and 83 references.