SBIR Phase II: Developing scale-up manufacturing of engineered waste coal ash based lightweight aggregate for concrete applications

这项小企业创新研究（SBIR）第二阶段项目的更广泛/商业影响是，通过使用热力学指导技术，在当地从废煤燃烧灰（W-CCA）中生产具有成本效益的工程化轻骨料（LWA），为混凝土行业增加建筑轻骨料（LWA）的可及性。由于制造商对原材料的依赖，传统的LWA制造商只能在美国的少数几个地方和州使用，因此，一些地区的LWA客户（例如，预拌混凝土供应商）支付超过70%的LWA价格，将LWA运输数百英里到他们的工厂。与此同时，煤灰填埋场丰富，分布在全国各地。据美国环保署称，由于垃圾填埋场建设和管理不当，超过500个W-CCA垃圾填埋场正在将有毒物质浸入地下水，其含量超过联邦安全标准。这些污染的后果是对环境、地下水和人类健康的持续破坏。通过将该技术应用到本地，以W-CCA生产工程化的LWA，既可以缓解LWA的供应链问题，也可以缓解W-CCA在垃圾填埋场积累的环境破坏。该项目的目标是扩大基于废煤燃烧灰（W-CCA）的轻质骨料（LWA）的生产规模，该骨料是通过热力学指导技术设计的。该产品将通过两步方法生产，以展示轻质混凝土生产中LWA的成功使用。该技术解决了从W-CCA生产LWA的主要挑战，即从一个填埋场到另一个填埋场的原料的化学成分变化。设计的LWA是基于原料W-CCA的化学成分和形成多孔LWA所需的条件。该项目将考虑最佳熔融相的形成量，部分熔融灰的适当粘度，以及灰中释放的气体形成孔隙。为了实现该项目的目标，将开发和测试批量生产的LWA，并根据相关的美国材料测试协会（ASTM）标准评估产品的性能，以证明其合规性。LCA产品将用于结构轻质混凝土的制备和表征，该团队将开发一个吨位级LWA生产的连续制造系统。最后，现场规模的混凝土将浇筑和表征使用生产的LWA在吨位规模。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。

The broader/commercial impact of this Small Business Innovation Research (SBIR) Phase II project seeks to increase the accessibility of construction lightweight aggregate (LWA) for the concrete industry using a thermodynamics-guided technology to locally produce a cost-effective and engineered LWA from waste coal combustion ash (W-CCA). The traditional LWA manufacturers are only available in few locations and states in the U.S. due to the manufacturers’ raw materials dependency, and therefore, LWA customers (e.g., ready-mix concrete suppliers) in some regions pay more than 70% of the LWA price to transport the LWA hundreds of miles to their plants. At the same time, coal ash landfills are abundant and are scattered around the country. According to the EPA, more than 500 W-CCA landfills are leaching toxic substances into the groundwater at levels exceeding federal safe standards due to improper landfill construction and management. The consequence of these contaminations is continuous damage to the environment, groundwater, and human health. By implementing this technology to produce an engineered LWA from W-CCA locally, both the supply chain issue of LWA and the environmental damage of W-CCA accumulated in the landfills will be alleviated.This project’s goal is to scale up manufacturing of a waste coal combustion ash (W-CCA) based lightweight aggregate (LWA), designed through a thermodynamics-guided technology. The product will be produced through a two-step approach to demonstrate the successful use of the LWA for lightweight concrete production. This technology addresses the main challenge of LWA production from W-CCA which is chemical composition variability in the feedstock from one landfill to another. The engineered LWA is based on the chemical composition of the raw W-CCA and the required conditions for the formation of a porous LWA. The project will consider formation of the optimal amount of molten phase, the appropriate viscosity for partially molten ash, and the gas release from the ash to form the pores. To achieve this project’s goal LWA manufacturing at batch scale will be developed and tested and the properties of the product will be assessed according to relevant American Society for Testing and Materials (ASTM) standards to demonstrate compliance. The product LCA will be used for structural lightweight concrete preparation and characterization and the team will develop a continuous manufacturing system for LWA production at tonnage scale. Finally, field scale concrete will be cast and characterized using the produced LWA at tonnage scale.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.