Comportement mécanique et durabilité du béton vert à base de ciment vert renforcé de plastique recyclé fonctionnalisé

机械性能和耐用性与水泥基性能和塑料回收功能

• 批准号: 571557-2021
• 负责人: Zimmermann, Elizabeth
• 金额: $ 3.28万
• 依托单位: McGill University
• 依托单位国家: 加拿大
• 项目类别: Alliance Grants
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=729185
• 关键词: Comportement; canique; et; durabilit; du

Background: Each year, value created by the Canadian construction industry totals over $250 billion USD. Here, reinforced concrete is an important technology because it can be formed into complex shapes and resists corrosive environments better than steel or wood. However, concrete's lifecycle has negative environmental effects, with cement production alone accounting for 5% of global CO2 emissions. Our long-term goal is to develop concrete with similar mechanical properties as current technology but with a lower carbon footprint and greater sustainability: green concrete. Our approach uses green cements reinforced with recycled plastic. Reinforcement with single-use plastics (polypropylene (PP), polyethylene terephthalate (PET)) can help manage plastic waste, while improving corrosion resistance and strength. To date, the success of plastic-cement composites has been very limited because plastic hydrophobicity prevents interaction with hydrophilic cements. Biological materials, such as seashells and bone, stem their excellent mechanical properties not only from their combination of biominerals and organic polymers, but also from the strong integration between these components. Inspired by these observations, we demonstrated that modifying the surface chemistry of plastic fibers by adding phosphate binding sites improves their integration with inorganic cements and subsequently increases the fracture toughness. These surface chemistry modifications are achieved using diazonium treatments, which we have shown to be extremely versatile with the ability to covalently bind phosphate and carboxylate moieties to a wide range of plastics.Our hypothesis is that cements with a lower carbon footprint reinforced with surface-treated recycled plastics will result in concrete with competitive mechanical behavior and improved sustainability compared to current standards. Our aims are to optimize diazonium treatments to functionalize plastic waste, examine and optimize mechanical behavior by varying cement composition and the geometry of plastic reinforcement, analyze material sustainability through artificial accelerated aging and perform a lifecycle assessment to investigate sustainability and environmental impact.Methods & Expertise: Green concrete will be fabricated from Portland and magnesium cements and reinforced with recycled plastic (PP, PET). Plastic surfaces will be treated with diazonium chemistry to introduce phosphate and carboxylate groups. Surface interactions will be investigated with electron microscopy and x-ray photo-electron spectroscopy. Mechanical properties will be measured in terms of compressive strength, bending strength and fracture toughness. Material sustainability will be assessed with artificial accelerated aging through fatigue testing, thermal cycling, and exposure to corrosive environments. A lifecycle assessment will analyze the full impact of the product from raw materials through disposal to determine the costs per year and the environmental impact in comparison to current technology.The team has complementary expertise in materials design, mechanical characterization in multi-scale materials, material surface modification and interface phenomena in materials, development of inorganic cements, and lifecycle analysis. Expected outcomes: If successful, the development of green concretes will reduce carbon emissions from the construction industry, promote the use of recycled materials, and increase sustainability of building materials.

背景：加拿大建筑业每年创造的价值总计超过 2500 亿美元。在这里，钢筋混凝土是一项重要的技术，因为它可以形成复杂的形状，并且比钢材或木材更能抵抗腐蚀环境。然而，混凝土的生命周期会对环境产生负面影响，仅水泥生产就占全球二氧化碳排放量的 5%。我们的长期目标是开发具有与当前技术相似的机械性能但碳足迹更低且可持续性更强的混凝土：绿色混凝土。我们的方法使用由再生塑料增强的绿色水泥。使用一次性塑料（聚丙烯 (PP)、聚对苯二甲酸乙二醇酯 (PET)）进行增强可以帮助管理塑料废物，同时提高耐腐蚀性和强度。迄今为止，塑料-水泥复合材料的成功非常有限，因为塑料的疏水性阻止了与亲水性水泥的相互作用。贝壳和骨骼等生物材料的优异机械性能不仅源于其生物矿物质和有机聚合物的结合，还源于这些成分之间的牢固结合。受这些观察的启发，我们证明，通过添加磷酸盐结合位点来改变塑料纤维的表面化学性质，可以改善它们与无机水泥的结合，从而提高断裂韧性。这些表面化学改性是通过使用重氮处理来实现的，我们已经证明重氮处理的用途极其广泛，能够将磷酸盐和羧酸盐部分与多种塑料共价结合。我们的假设是，与现行标准相比，用表面处理的再生塑料增强碳足迹较低的水泥将产生具有竞争力的机械性能和更高的可持续性的混凝土。我们的目标是优化重氮处理，使塑料废物功能化，通过改变水泥成分和塑料增强材料的几何形状来检查和优化机械行为，通过人工加速老化分析材料的可持续性，并进行生命周期评估以调查可持续性和环境影响。方法和专业知识：绿色混凝土将由波特兰和镁水泥制成，并用再生塑料（PP、 宠物）。塑料表面将经过重氮化学处理以引入磷酸盐和羧酸盐基团。表面相互作用将通过电子显微镜和 X 射线光电子能谱进行研究。机械性能将通过压缩强度、弯曲强度和断裂韧性来测量。将通过疲劳测试、热循环和暴露于腐蚀性环境中，通过人工加速老化来评估材料的可持续性。生命周期评估将分析产品从原材料到处置的全部影响，以确定每年的成本以及与现有技术相比对环境的影响。该团队在材料设计、多尺度材料的机械表征、材料表面改性和材料界面现象、无机水泥的开发以及生命周期分析方面拥有互补的专业知识。 预期成果：如果成功，绿色混凝土的开发将减少建筑行业的碳排放，促进再生材料的使用，并提高建筑材料的可持续性。