A novel biomimetic design of a 3D vascular structure for self-healing in cementitious materials using Murray's law

Abstract

Nature has always been a source of inspiration in engineering applications and vascular networks, as in human skin and in a tree leaf, are one attribute that has received attention in the design of resilient structures. A vascular system houses healing agents within its hollow channels or interconnected networks which are incorporated within a cement matrix. It is the only self-healing approach that has the capability to address different scales of damage in cementitious materials. The main aim of this work is to develop a novel vascular network inspired by nature for self-healing in cementitious systems. To achieve this, a biomimetic three-dimensional (3D) vascular network was designed and generated following Murray's law for circulatory blood volume transfer. The designed structures were constructed through 3D printing and assessed in a cement-based matrix. One-dimensional (1D) and two-dimensional (2D) models were also designed, printed and embedded into cement prisms to compare with the 3D vascular system. Load recovery was used to assess recovery in mechanical properties after the sample was cracked and pumped with sodium silicate for 28 days. Mechanical testing assessed the compatibility of the system with the surrounding matrix as well as the functionality of the network in delivering and releasing the healing agent at the location of damage. This initial proof of concept work confirmed the ability of all vascular systems to deliver the healing agent after a damage event, and the 3D vascular system demonstrated a significantly enhanced healing performance. Keywords: Vascular networks, Biomimetic structures, 3D printing, Self-healing, Cementitious materials