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

这个小型企业创新研究(SBIR)第二阶段项目的更广泛的商业影响是寻求增加混凝土行业建筑轻集料(LWA)的可及性，使用热力学指导的技术在当地从废弃的燃煤灰渣(W-CCA)中生产具有成本效益的工程轻集料(W-CCA)。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点和州提供，因此，一些地区的LWA客户(如预拌混凝土供应商)需要支付超过LWA价格的70%，才能将LWA运送到数百英里外的工厂。与此同时，火山灰垃圾填埋场资源丰富，分布在全国各地。根据EPA的数据，由于垃圾填埋场建设和管理不当，500多个W-CCA垃圾填埋场正在向地下水中淋洗有毒物质，其水平超过了联邦安全标准。这些污染的后果是对环境、地下水和人类健康的持续破坏。通过在当地实施这项技术以W-CCA为原料生产工程化的LWA，将缓解LWA的供应链问题和W-CCA在垃圾填埋场积累的环境破坏。该项目的目标是扩大生产基于废燃煤灰渣(W-CCA)的轻集料(LWA)，通过热力学指导技术进行设计。该产品将通过两步法生产，以展示LWA在轻质混凝土生产中的成功使用。这项技术解决了从W-CCA生产LWA的主要挑战，即从一个垃圾填埋场到另一个垃圾填埋场的原料中化学成分的差异。工程LWA是基于原始W-CCA的化学成分和形成多孔LWA所需的条件。该项目将考虑形成最适量的熔融相，部分熔融的火山灰的适当粘度，以及从火山灰中释放出形成气孔的气体。为了实现该项目的目标，将开发和测试批量LWA制造，并将根据相关的美国测试与材料协会(ASTM)标准对产品的性能进行评估，以证明其合规性。该产品LCA将用于结构轻质混凝土的制备和表征，该团队将开发一种连续生产系统，用于吨位规模的LWA生产。最后，现场规模的混凝土将使用生产的吨位规模的LWA进行浇注和表征。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。

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.