Engineered Concrete through Tailored Cementitious Materials by Tribochemistry, Surface Treatment and Activation

通过摩擦化学、表面处理和活化定制水泥材料的工程混凝土

• 批准号: RGPIN-2016-05985
• 负责人: TagnitHamou, Arezki
• 金额: $ 3.06万
• 依托单位: Université de Sherbrooke
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=616030
• 关键词: Engineered; Concrete; through; Tailored; Cementitious

The production of cement—the world’s most widely used construction material—causes about 5% of the total CO2 caused by human activity. The cement/concrete industries have committed to reduce their greenhouse emissions by reducing the amount of cement clinker in concrete. One such means is using supplementary cementitious materials (SCMs) from industrial by-products (silica fume, slag, fly ash) and alternative SCMs (ASCMs: glass powder, metakaolin, calcined clays) that can partially or totally replace cement in concrete. Although concretes with SCMs can yield equivalent or higher properties than plain concrete, their potential has yet to be fully be exploited. In any cases, low early strength, long setting time, poor dispersion, slow reactivity, chemical shrinkage, and concrete cracking are reported. This research program focuses on optimizing SCM properties with tribochemistry, surface chemical activation, dispersion, and packing-density tools to design durable, sustainable concrete structures. The grinding of solid-like cement and SCMs generates complex transformations. The mechanical energy disrupts the materials’ atomic and molecular structures, producing cracks, micro-defects and new surfaces. The energy in the micro-defects of the crystalline structure can modify and complexify solid-particle reactivity and rheology. This effect is more complex when different materials (clinker, SCMs, ASCMs) are interground. Chemical activation can also be used to increase SCM and ASCM hydration. In this program, SCMs will be tailored through grinding and surface treatment to engineer concretes with high particle-packing densities. The milled surface-treated mixtures will be analyzed with microscopic and spectroscopic techniques. Tribochemical effects of SCMs will be investigated on binder hydration and activation of portland cement-free binders through calorimetry, nano-indentation, and electron-microscopic measurements. Understanding the effect of material grinding on particle surfaces (tribochemistry) and surface treatment coupled with an optimized packing density of the binder will provide better mastery over the hydration process. These synergetic effects will be modulated to tailor a concrete with optimized rheology, mechanical performances, and durability. Results obtained from this modeling will be validated on pilot-scale and in situ experimental concretes. In addition to train HQP readily available for the Canadian construction industry, the outcome will be a major database and model accessible to the concrete industry for building durable and sustainable infrastructures in Canada.

水泥（世界上使用最广泛的建筑材料）的生产产生的二氧化碳约占人类活动产生的二氧化碳总量的 5%。水泥/混凝土行业致力于通过减少混凝土中水泥熟料的用量来减少温室气体排放。其中一种方法是使用来自工业副产品（硅粉、矿渣、粉煤灰）的补充胶凝材料（SCM）和替代性SCM（ASCM：玻璃粉、偏高岭土、煅烧粘土），可以部分或全部替代混凝土中的水泥。尽管含有 SCM 的混凝土可以产生与素混凝土相同或更高的性能，但其潜力尚未得到充分开发。在任何情况下，都会出现早期强度低、凝结时间长、分散性差、反应性慢、化学收缩和混凝土开裂等问题。该研究项目的重点是通过摩擦化学、表面化学活化、分散和堆积密度工具优化 SCM 性能，以设计耐用、可持续的混凝土结构。 固体状水泥和 SCM 的研磨会产生复杂的转变。机械能会破坏材料的原子和分子结构，产生裂纹、微观缺陷和新表面。晶体结构的微观缺陷中的能量可以改变和复杂化固体颗粒的反应性和流变性。当不同材料（熟料、SCM、ASCM）相互研磨时，这种影响会更加复杂。化学活化也可用于增加 SCM 和 ASCM 水合作用。在此计划中，SCM 将通过研磨和表面处理进行定制，以设计具有高颗粒堆积密度的混凝土。研磨后的表面处理混合物将通过显微镜和光谱技术进行分析。将通过量热法、纳米压痕和电子显微镜测量来研究 SCM 对粘合剂水合和无波特兰水泥粘合剂活化的摩擦化学效应。 了解材料研磨对颗粒表面（摩擦化学）和表面处理的影响以及优化的粘合剂堆积密度将有助于更好地掌握水合过程。这些协同效应将被调节以定制具有优化流变性、机械性能和耐久性的混凝土。 从该模型获得的结果将在中试规模和现场实验混凝土上进行验证。 除了为加拿大建筑业提供随时可用的 HQP 培训之外，成果还将是一个可供混凝土行业使用的主要数据库和模型，用于在加拿大建设耐用和可持续的基础设施。