Preparation technology and toughening mechanism of a bionic high-toughness cement-based composite
To enhance the toughness of the concrete matrix,based on the unique"brick-mortar"structure of shell nacre,a bionic high-toughness cement-based composite material with"brick-bridge-mortar"structure was prepared using cement stone and organic polymers.The flexural strength,toughness,and toughening mecha-nism of bionic cement-based materials were studied by three-point bending test,scanning electron microscopy and finite element simulation.The results indicate that compared with the brittle fracture mode observed in con-ventional cement,bionic toughened cement-based materials exhibit evident ductile fracture properties,including a gradual reduction in the post-peak curve and a significant augmentation in mid-span deflection.Based on the multi-scale bridging-stretching effect of organic polymers,the bionic toughened cement-based materials exhibit clear crack deflection and branching phenomena internally,which reflects the internal and external collaborative toughening mechanism of the bionic"brick-bridge-mortar"structure.These materials can increase the toughness of the cement matrix by 179.45％,while ensuring 95％flexural strength.This finding offers new technique route to solve the problem of enhancing toughness and reducing brittleness in concrete materials.
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