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.

水泥是世界上使用最广泛的建筑材料，其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/混凝土行业已承诺通过减少混凝土中水泥熟料的数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（硅灰、矿渣、粉煤灰）的补充胶凝材料（SCMs）和替代胶凝材料（ascm：玻璃粉、偏高岭土、煅烧粘土），这些材料可以部分或完全取代混凝土中的水泥。虽然具有SCMs的混凝土可以产生相当于或高于普通混凝土的性能，但它们的潜力尚未得到充分利用。在任何情况下，早期强度低，凝结时间长，分散性差，反应性慢，化学收缩，混凝土开裂。本研究项目侧重于利用摩擦化学、表面化学活化、分散和填充密度工具来优化SCM性能，以设计耐用、可持续的混凝土结构。