SusChEM: Environmentally sustainable concretes enabled by multiscale investigation of ancient Roman concretes

SusChEM：通过对古罗马混凝土的多尺度研究实现环境可持续混凝土

• 批准号: 1410557
• 负责人: Roya Maboudian
• 金额: $ 49.77万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2018-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1410557&HistoricalAwards=false
• 关键词: SusChEM; Environmentally; sustainable; concretes; enabled

NON-TECHNICAL DESCRIPTION: Production of concrete based on Portland cement hydration is an energy intensive process responsible for a staggering 5-8% of the annual global CO2 emissions. The concretes of ancient Roman monuments and seawater harbors, produced from volcanic rocks and hydrated lime, have a far smaller CO2 footprint than conventional Portland cement concretes, far greater chemical and mechanical resistance to decay, and take a smaller energy budget to produce. The secret to the environmental sustainability of the 2000-year old concretes is traced to the chemical nature of the mortar binder. The goal of the project is to gain a fundamental understanding of this chemistry. The broader impact of this work lies in its positive contributions to interdisciplinary science, society, and educational and outreach activities. The research will provide guideposts for greater sustainability of our resources (both energy and clean water) and future applications to high performance concretes, as well as to increased durability of Portland cement concretes blended with environmentally-friendly supplemental materials, and including seawater, which conserves fresh water resources. From a societal perspective, the research has the potential to transform traditional concepts of the concrete industry based on Portland cement hydration, to binding mechanisms inherent in naturally-occurring volcanic ash deposits. The results may also be of value in developing improved methods for conservation of ancient structures and more recent concrete structures. From an economic perspective, it will contribute to "green" construction, an important growth sector of the national economy. TECHNICAL DESCRIPTION: This project aims to gain a fundamental understanding of the hydration mechanisms, binding mechanisms, cation exchange properties, and nanoscale mechanical properties of 2000-year old cementitious components of Roman concretes. The research is based on a nanostructural approach that focusses on thin, intact slices of mortars, already prepared from the Baianus Sinus breakwater (first century BC) in Pozzuoli Bay near Naples, Italy, and reproductions of these materials prepared with Campi Flegrei volcanic ash. The primary analytical techniques include X-ray microdiffraction (to identify crystalline phases), Raman spectroscopy (for structural and vibrational properties and bonding environment characterization), nuclear magnetic resonance (for Si-O and Al-O bonding environments), high-resolution transmission electron microscopy (for detailed nanostructural studies), nanoindentation to assess mechanical properties of these phases (modulus, hardness, strength) with nanoscale resolution, and engineering strength and durability testing for the mortar reproductions. It is anticipated that this research will result in new formulations of high performance concretes with a lifetime improvement of over one order of magnitude, and in new processes designed specifically for reduced waste product, especially CO2 emissions, and for much higher energy efficiency than current processes. A significant impact of this project is in education, in particular by training graduate and undergraduate students in several disciplinary areas: materials science, earth science, archaeological science, and civil engineering.

非技术描述：基于波特兰水泥水化的混凝土生产是一个能源密集型过程，其二氧化碳排放量占全球年度二氧化碳排放量的惊人5-8%。古罗马古迹和海港的混凝土由火山岩和熟石灰制成，其二氧化碳排放量远小于传统的波特兰水泥混凝土，具有更强的化学和机械抗腐蚀性，并且生产所需的能源预算更少。 2000年历史的混凝土的环境可持续性的秘密可以追溯到砂浆粘合剂的化学性质。该项目的目标是获得对这种化学的基本了解。 这项工作的广泛影响在于它对跨学科科学、社会、教育和外联活动的积极贡献。该研究将为我们的资源（能源和清洁水）的更大可持续性和未来高性能混凝土的应用提供指导，以及增加与环保补充材料混合的波特兰水泥混凝土的耐久性，包括海水，这将节省淡水资源。从社会的角度来看，这项研究有可能改变传统的概念，混凝土工业的基础上波特兰水泥水化，在自然发生的火山灰沉积固有的约束机制。研究结果也可能是有价值的，在开发改进的方法，保护古代结构和更近的混凝土结构。 从经济角度看，将有助于“绿色”建设这一国民经济的重要增长板块。技术说明：该项目旨在对2000年前罗马混凝土的水泥基成分的水化机制、结合机制、阳离子交换性能和纳米级机械性能有一个基本的了解。这项研究是基于一种纳米结构的方法，重点是薄，完整的砂浆片，已经准备从拜亚努斯窦防波堤（公元前世纪）在波佐利湾附近的那不勒斯，意大利，和复制品的这些材料准备与坎皮Flegrei火山灰。主要的分析技术包括X射线微衍射（用于识别晶相）、拉曼光谱（用于结构和振动特性以及键合环境表征），核磁共振（Si-O和Al-O键合环境），高分辨率透射电子显微镜（用于详细的纳米结构研究），纳米压痕以评估这些相的机械性能（模量、硬度、强度），以及砂浆复制品的工程强度和耐久性测试。预计这项研究将导致高性能混凝土的新配方，其寿命提高超过一个数量级，并在专门为减少废物，特别是二氧化碳排放量而设计的新工艺中，以及比当前工艺高得多的能源效率。该项目对教育产生了重大影响，特别是通过培训几个学科领域的研究生和本科生：材料科学，地球科学，考古学和土木工程。