Collaborative Research: 3D Printing of Civil Infrastructure Materials with Controlled Microstructural Architectures

该合作项目将使用增材制造（3D打印）来设计水泥基材料的微观结构，并制造水泥基结构，以其他方式无法实现，控制材料的局部成分及其组件的空间排列。该研究的目标是了解控制水泥基材料3D打印过程的主要因素，以及如何设计打印的长丝层之间以及长丝夹杂物和固体基质相之间的界面相互作用。通过使用增材制造，拟议的研究项目有可能通过提供表现出范式转变特性的材料，实现现有材料无法实现的新功能，从而在高性能基础设施材料领域取得重大进展。最终，3D打印工艺将能够制造轻质和模块化结构和建筑物，以便在自然灾害和水泥基材料以前没有竞争力的产品应用中快速部署。教育部分将利用三个机构中每个机构的现有项目，包括为本科生和研究生开发教学材料，以及为不同的本科生群体提供研究机会。这项合作研究的目标是从根本上了解（1）化学，印刷长丝层固化，和3D打印连续分层沉积工艺条件以及（2）控制结合机制的打印层之间的界面相互作用。预计3D打印将通过功能组件中的连续梯度实现材料特性的受控空间变化。细丝层固化过程和界面特性的实验研究将与计算分析相结合，包括分子尺度结构的分子动力学模拟，能量学和细丝间和界面的机械性能，以揭示支撑结构材料的加工/制造微结构性能关系的物理-化学-机械机制。该研究将（1）提供细丝层之间以及细丝夹杂物和基质界面之间的化学机械相互作用的分子到纳米尺度的图片，（2）确定界面处结构的关键方面，以实现表面和打印介质化学的细化，以及（3）为理解和开发水泥系统的新方法的开发提供见解。

This collaborative project is to use additive manufacturing (3D printing) to engineer the microstructure of cement-based materials and fabricate cement-based structures with otherwise unachievable, controlled local composition of the material and spatial arrangement of its components. The goal of the research is to understand the major factors controlling the 3D printing process of cement-based materials and how to design interfacial interactions between printed filament layers and between filament inclusions and solid matrix phases. Though the use of additive manufacturing, the proposed research project has the potential to enable significant progress in the fields of high-performance infrastructure materials by providing materials that exhibit paradigm-shifting properties allowing new functionalities that are not achievable with existing materials. Ultimately, the 3-D printing processes will enable the fabrication of light-weight and modular structures and buildings for rapid deployment in cases of natural disasters and product applications wherein cement-based materials have not previously been competitive. The educational component will leverage existing programs of each of the three institutions and includes the development of instructional materials for undergraduate and graduate students and research opportunities for a diverse group of undergraduate students.The goal of this collaborative research is to fundamentally understand (1) the intertwined mechanisms between chemistry, printed filament layer solidification, and 3D printing successive-layering-deposition process conditions and (2) the interfacial interactions between printed layers that control the bonding mechanism. 3-D printing is anticipated to enable the controlled spatial variation of material properties through continuous gradients in functional components. Experimental investigations of the filament layer solidification process and of the interfacial characteristics will be integrated with computational analysis, including molecular dynamics simulations of the molecular scale structure, energetics, and mechanical properties of the inter-filament and interfaces to unravel the physico-chemo-mechanical mechanisms that underpin the processing/manufacturing-microstructure-property relationship of the architectured materials. The research will (1) provide a molecular to nanoscale picture of the chemo-mechanical interactions between filament layers and between the filament inclusions and matrix interfaces, (2) identify key aspects of the structure at interfaces necessary to enable refinement of surfaces and printing media chemistry, and (3) provide insights into the development of a new approach to understanding and developing cementitious systems.