A Carbon Negative Self-Healing Enzymatic Construction Material

混凝土是仅次于水的地球上消耗最多的材料。每年，建筑产生的废弃混凝土以及水泥生产和运输产生的二氧化碳排放量都在增加，现在仅混凝土一项就占总二氧化碳排放量的9%。此外，混凝土天生就是易碎的，需要经常维修和更换，这在经济上是昂贵的，而且还会产生大量二氧化碳。几十年来，科学家们一直在努力寻找环境友好、成本低廉的混凝土替代品。该奖项的目标是利用建模和实验相结合的框架创建一种新的廉价、碳负向、自我修复的建筑材料。这种材料利用一种安全、普遍存在的生物酶，可以在生产过程中有效地捕获二氧化碳。使用这一新的范例，将产生一种自我修复的酶构建材料。这种酶建筑材料在捕获碳的同时，可以显著延长民用基础设施的使用寿命。据预测，一立方码的酶建筑材料大约可以储存18磅二氧化碳。相比之下，一立方码的混凝土排放约400磅二氧化碳。除了研究任务，还将培训研究生和本科生，并制定一个项目，帮助贫困女孩学习建筑和工程。受到酶在细胞内高效运输二氧化碳的启发，引入了一种新的范例来创造具有自我修复性能的酶结构材料。碳酸酐酶催化碳酸钙结晶沉淀，沿着聚合物支架建立矿物桥，将聚集体结合在一起。因此，材料的固化可以在短时间内在低温下进行。这种材料的平均强度值是水泥砂浆最低要求的三倍，而且还能够在骨折后持续多次愈合。该项目的科学贡献包括以下几点。(1)酶促结晶沉淀法合成新型建筑材料。通过酶机制的结晶沉淀速度比细菌方法快四个数量级，使其可扩展到工业应用中。(2)酶机理为碳负材料的发展提供了一种手段，最终取代混凝土。(3)一种新的基于涨落的半正则蒙特卡罗模拟方法将被用作酶建筑材料热力学行为的建模技术。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Second only to water, concrete is the most consumed material on earth. Every year, waste concrete from construction and carbon dioxide excretion from cement production and transport is increasing, and concrete alone now contributes to 9 percent of the overall CO2 emissions. Additionally, concrete is inherently brittle, and it requires frequent repair and replacement, which are economically expensive and further generate large volumes of carbon dioxide. Scientists have been trying to find environmentally friendly and low-cost substitutes for concrete for decades. The goal of this award is to create a new class of inexpensive, carbon-negative, self-healing construction materials using a combined modeling and experimental framework. The material utilizes a safe, ubiquitous, biological enzyme that can efficiently capture CO2 during its production. Using this new paradigm, a self-healing Enzymatic Construction Material will be produced. This Enzymatic Construction Material can significantly lengthen the service life of civil infrastructure while capturing carbon. It is predicted that one cubic yard of Enzymatic Construction Material will approximately store 18 pounds of CO2. In contrast, one cubic yard of concrete emits around 400 pounds of CO2. The research tasks will be complemented by training both graduate and undergraduate students and developing a program to help inspire underprivileged girls to learn about construction and engineering. Inspired by the efficient process of CO2 transport in cells by enzymes, a new paradigm is introduced to create the Enzymatic Construction Material with self-healing properties. The enzyme, carbonic anhydrase, catalyzes calcium carbonate crystal precipitation, establishing mineral bridges along the polymer scaffolding that bonds the aggregate together. Hence, curing of the material can be performed at low temperatures in a short timeframe. The material exhibits an average strength value that is three times as high as the minimum requirement for cement mortar and is also capable of sustaining many cycles of healing after fracture. The scientific contribution of the project includes the following. (1) The formulation of a new class of construction materials through enzymatic crystal precipitation. The rate of crystal precipitation through the enzymatic mechanism is four orders of magnitude faster than bacterial methods making it scalable to industrial applications. (2) The enzymatic mechanism provides a means for the development of carbon-negative materials to ultimately replace concrete. (3) A novel fluctuation-based Semi-Grand Canonical Monte Carlo simulation method will be used as a modeling technique for the thermodynamic behavior of the Enzymatic Construction Material.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.