Collaborative Research: Engineering Fracture Response and Transport Behavior in Additively Manufactured, Layered Concrete Materials

合作研究：增材制造的层状混凝土材料的工程断裂响应和传输行为

• 批准号: 2129566
• 负责人: Reza Moini
• 金额: $ 35.89万
• 依托单位: Princeton University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2129566&HistoricalAwards=false
• 关键词: Collaborative; Research; Engineering; Fracture; Response

This research focuses on the development of a new generation of 3D-printed cementitious materials with enhanced performance. Layered, 3D-printed concrete components are being developed in infrastructure and housing construction. However, broad adoption of these components by the construction industry is impeded by less-than-satisfactory mechanical properties and durability. As such, there is an urgency to better understand and improve performance of 3D-printed concrete materials. This research will gain fundamental understanding of the internal arrangements of 3D-printed concrete at the micron scale and explore layer deposition to tailor the internal structure of these novel materials and enhance mechanical and fracture properties, as well as the long-term durability and safety. This research will push forward the boundaries of knowledge, leading to transformative engineering solutions, broad implications, and recommendations transferable to large-scale applications where concrete is used, such as homes, buildings, roads, and bridges. Findings from this research has the potential to improve conventional concrete infrastructures, such as advancing curing and slip-form construction. The educational and outreach activities will provide opportunities for students (including graduate, undergraduate, and K-12 students) to learn about new directions and career prospects in civil engineering. The research will achieve a foundational understanding of the physics of 3D-printed concrete in several temporal and spatial scales. Material characterization will be conducted during extrusion, 3D-printing, and hardening stages using neutron radiography, micro-computed tomography, X-ray diffraction, and elemental mapping of interfacial zones and filaments. The research will answer fundamental questions about the mechanisms involved in the extrusion process, such as the formation of a so-called “lubrication layer”. The research will examine the hypothesized ways in which this water-rich layer can de-homogenize and control the spatial water distribution within the tube/barrel prior to deposition, after deposition (during the knitting/bonding), and the spatial morphology and connectivity of the pore network and hydrated compounds surrounding the interfaces. The knowledge will then be used to inform designs of the internal architecture of the material with the goal of tailoring fracture response and transport behavior. By engineering the weak attributes of the interfaces with internal helical architectures, this research will enhance mixed-mode fracture toughness in 3D-printed cementitious materials based on linear elastic fracture mechanics principles. By engineering intentional flaws and tailoring the morphology of the pore network, the fluid-transport behavior in these materials will be controlled.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

本研究的重点是开发具有增强性能的新一代3d打印胶凝材料。分层的3d打印混凝土组件正在基础设施和住房建设中得到开发。然而，由于机械性能和耐久性不太令人满意，建筑行业对这些部件的广泛采用受到阻碍。因此，迫切需要更好地了解和提高3d打印混凝土材料的性能。本研究将在微米尺度上对3d打印混凝土的内部结构有基本的了解，并探索层沉积，以定制这些新材料的内部结构，提高机械和断裂性能，以及长期耐久性和安全性。这项研究将推动知识的边界，导致变革性的工程解决方案，广泛的影响和建议，可转移到使用混凝土的大规模应用中，如房屋，建筑物，道路和桥梁。这项研究的发现有可能改善传统的混凝土基础设施，如推进养护和滑模施工。教育和推广活动将为学生（包括研究生，本科生和K-12学生）提供机会，了解土木工程的新方向和职业前景。该研究将在几个时间和空间尺度上实现对3d打印混凝土物理的基本理解。材料表征将在挤压、3d打印和硬化阶段进行，使用中子射线照相、微计算机断层扫描、x射线衍射以及界面区和细丝的元素映射。这项研究将回答有关挤压过程中涉及的机制的基本问题，例如所谓的“润滑层”的形成。该研究将研究富水层在沉积前、沉积后（编织/粘合过程中）去均质化和控制管/桶内空间水分布的假设方式，以及孔隙网络和界面周围水合化合物的空间形态和连通性。然后，这些知识将用于材料内部结构的设计，目标是定制断裂响应和传输行为。本研究将基于线弹性断裂力学原理，通过对具有内螺旋结构界面的弱属性进行工程化处理，提高3d打印胶凝材料的混合模式断裂韧性。通过设计有意的缺陷和调整孔隙网络的形态，这些材料中的流体传输行为将得到控制。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。