Title:
Fracture Mechanics of Tough and Ductile Nacre-like Cementitious Composites
Author(s):
Gupta
Publication:
Web Session
Volume:
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
11/3/2024
Abstract:
Enhancing fracture toughness and ductility of brittle materials such as concrete remains a challenge. Nature offers numerous solutions to enhance fracture toughness without sacrificing strength using purposeful designs of materials architecture. Here, we propose a bioinspired “nacre-like” brick-and-mortar arrangement from mollusk shells, enabled by laser processing and periodic tabulating of cement paste laminated with limited amounts of elastomeric interlayers. These new “nacre-like” architected composites reproduce tablet sliding and interlayer deformation toughening mechanisms that are present in natural nacre and promote higher fracture toughness but absent in human-made brittle and quasi-brittle materials such as cement paste and concrete. By engineering laser-induced defects and tabulated arrangements of hard-soft materials, we produce interlayer deformation, tablet sliding, and tortuous crack propagation as toughening mechanisms such that both fracture toughness and ductility are significantly enhanced, by one order of magnitude, compared to the constituent brittle cement paste. These toughening mechanisms also promote rising R-curves in “nacre-like” composites compared to the flat brittle response of monolithic cement paste. We leverage bio-inspired design principles to program toughening into internal schemes of these hard-soft cementitious composites. The findings of this research can help develop a strategy to enhance the toughness of concrete materials by harnessing internal flaws and incorporation of small amounts of soft hyperelastic materials. This approach could lead to generate flaw-tolerant and impart crack-resistant characteristics in brittle cementitious material at large scale, for example using largescale lamination or additive manufacturing techniques.