Jiangsu Key Laboratory of Construction Materials, School of Materials Science and Engineering, Southeast University, Nanjing 211189, China.
Laboratoire Navier, IFSTTAR / CNRS / ENPC, Université Gaustave Eiffel, Champs-sur-Marne 77420, France.
ACS Appl Mater Interfaces. 2020 Nov 25;12(47):53297-53309. doi: 10.1021/acsami.0c15313. Epub 2020 Nov 10.
Because of the inherent quasibrittleness and heterogeneity, matrix-directed toughening of concrete and cement composites remains to be a huge challenge. Herein, inspired by nacre materials, a novel biomimetic bulk cement composite is fabricated via a facile and efficient process based on compacting prefabricated multisized cement-polymer hybrid prills. This method combines with the three-dimensional "brick-bridge-mortar" structure design and synchronously the intrinsic and extrinsic toughening strategies. Such an approach shows the remarkable maximum toughness enhancement of 27-fold with 71% increase in flexural strength via cooperation with only 4 wt % organic matter. More attractively, it alters the traditional brittle fracture of cement composites to a distinct ductile fracture. In addition, such a biomimetic composite demonstrates the long-term ever-increasing strength and toughness, performing the excellent ductile-fracture retention ability. The hierarchical toughening mechanisms are further revealed with the synergy of microscopic characterizations and simulation methods. This strategy provides a new route for the development of high toughness biomimetic cement-based materials for potential applications in civil engineering domain.
由于混凝土和水泥基复合材料固有的准脆性和异质性，基于基体的增韧仍然是一个巨大的挑战。受珍珠母材料的启发，本文通过一种简单有效的方法制备了一种新型仿生整体水泥复合材料，该方法基于压缩预制的多尺寸水泥-聚合物杂化颗粒。该方法结合了三维“砖-桥-砂浆”结构设计和内在及外在增韧策略。通过与仅 4wt%的有机物协同作用，这种方法显示出显著的最大韧性增强 27 倍，弯曲强度提高 71%。更吸引人的是，它将水泥复合材料的传统脆性断裂转变为明显的韧性断裂。此外，这种仿生复合材料表现出长期持续增加的强度和韧性，具有优异的韧性断裂保持能力。通过微观表征和模拟方法的协同作用，进一步揭示了分层增韧机制。该策略为开发用于土木工程领域的高韧性仿生水泥基材料提供了新途径。
