Optimization of eco-friendly mixtures composed by granite-based crushed aggregates and inert fillers for structural applications

用于结构应用的由花岗岩碎骨料和惰性填料组成的环保混合物的优化

• 批准号: 530552-2018
• 负责人: MorettiSanchez, LeandroFrancisco
• 金额: $ 1.6万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=660190
• 关键词: Optimization; eco; friendly; mixtures; composed

Pressure is mounting in the civil construction industry to adopt more environmentally sustainable methods to reduce CO2 emissions. As the most commonly used construction material in the world, concrete has a particularly significant environmental impact, which continues to increase at a rapid rate. Global demand for concrete has increased by 400% between 1990 and 2002, and a 2.5-fold increase in global cement production is expected over the next 40 years. Portland cement often constitutes to more than two-thirds of the embodied energy of concrete, and its production generates 5% of global greenhouse gas emissions. A novel strategy to reduce Portland cement content in mixtures, without sacrificing performance, is the use of particle packing models and inert filler materials, which have lower or similar particle-size distribution than Portland cement. By reducing the volume to be filled by cement paste, Portland cement content can be significantly reduced by more than 50% in some cases. Moreover, the use of the bi index (i.e., the amount of binder required to produce 1 MPa of property, for example, compressive strength, has been used to quantify how environmentally friendly concrete mixtures may be, with typical values ranging from 10 to 15 [kg/m³.MPa] for standard conventional mixes. The embodied energy of concrete is also directly linked to extraction and transportation of aggregates and other raw materials that comprise concrete mixes. Furthermore, the use of river sand as a source of fine aggregates has led to the depletion of natural resources, lowering the water table, and posing other agricultural challenges. To address this concern, crushed stone waste, presenting particle-size distributions similar to sand (i.e. manufactured sand), or even lying between those of sand and Portland cement, has been proposed as an alternative to river sand. It has been shown that sources of good quality aggregates near construction sites can minimize transportation costs and energy use, while the fine residues generated during the crushing process (i.e. manufactured sand and inert fillers), may be used as a partial replacement for Portland cement. Hence, using coarse/fine aggregates (Particle Size>100 µm) and inert fillers (Particle Size<100 µm) from local quarries can be a novel strategy to produce eco-efficient concrete materials with a significantly reduced environmental footprint. Moreover, there is a lack of consistent and scientific mix-design procedures, especially addressing particle-packing model techniques, accounting for alternative fine residues in eco-friendly concrete. The proposed research project will focus on develop a new mix- design procedure including particle packing techniques to design low-cement concrete mixtures for structural applications, and evaluate the use of granite-based quarry processing materials and by-products, particularly crushed aggregates and inert fillers to produce eco-friendly low cement concrete with interesting short and long-term performance. The scientific benefit of this CRD include the development of a new performance-based design methodology for proportioning eco-friendly mixtures using locally available materials, which can significantly reduce the overall environmental impact of concrete suppliers and contractors across Canada. This result is expected to create new revenue streams for Fowler for fine granite-based aggregate production, which is not currently used for concrete applications, as well as a new opportunity for using quarry by-products.

土木建筑行业面临越来越大的压力，要求采用更环保的方法来减少二氧化碳排放，混凝土作为世界上最常用的建筑材料，对环境的影响尤为显着，全球对混凝土的需求持续快速增长。 1990 年至 2002 年间，混凝土用量增加了 400%，预计未来 40 年全球水泥产量将增加 2.5 倍，波特兰水泥通常占混凝土蕴含能源的三分之二以上。其生产产生的温室气体排放量占全球的 5%，在不牺牲性能的情况下减少混合物中波特兰水泥含量的新策略是使用颗粒填充模型和惰性填充材料，其粒度分布低于或相似于波特兰。通过减少水泥浆的填充量，在某些情况下，波特兰水泥含量可以显着减少 50% 以上，此外，使用 bi 指数（即生产 1 MPa 的水泥所需的粘结剂用量）。财产，例如，抗压强度已被用来量化混凝土混合物的环保程度，标准传统混合物的典型值范围为 10 至 15 [kg/m3.MPa]。混凝土的隐含能量也直接相关。此外，使用河沙作为细骨料的来源导致自然资源枯竭，地下水位下降，并带来其他农业挑战。这令人担忧的是，碎石废料的粒度分布与沙子（即机制砂）相似，甚至介于沙子和波特兰水泥之间，已被提议作为河沙的替代品。事实证明，其来源质量良好。建筑工地附近的骨料可以最大限度地减少运输成本和能源使用，而破碎过程中产生的细残留物（即机制砂和惰性填料）可以部分替代硅酸盐水泥，因此，使用粗/细骨料（颗粒）。来自当地采石场的颗粒尺寸>100微米）和惰性填料（颗粒尺寸<100微米）可以成为生产生态高效混凝土材料的一种新颖策略，同时显着减少环境足迹。此外，缺乏一致和科学的配合比设计。程序，特别是解决颗粒填充模型技术，考虑环保混凝土中的替代细残留物。拟议的研究项目将重点开发一种新的配合比设计程序，包括颗粒填充技术，以设计用于结构应用的低水泥混凝土混合物，和评估使用花岗岩采石场加工材料和副产品，特别是碎骨料和惰性填料来生产具有有趣的短期和长期性能的环保低水泥混凝土，该 CRD 的科学效益包括开发一种新的技术。基于性能的设计方法，使用当地可用的材料配制环保混合物，可以显着减少加拿大各地混凝土供应商和承包商的整体环境影响，这一结果预计将为 Fowler 的细花岗岩骨料生产创造新的收入来源。 ，即目前尚未用于具体应用，同时也是使用采石场副产品的新机会。