Properties of Lightweight Self Consolidating Concrete

轻质混凝土(LWC)和自固结混凝土(SCC)在建筑业中得到了广泛的应用。SCC是一种高流动性、高性能的混凝土，无需使用振动器即可在自身重量下轻松展开，并实现所需的固结。LWC已在许多不同的应用中使用，并以其性能和耐用性而闻名。虽然两者的经济、实用和技术效益都是众所周知的，但由于轻集料和正常重量砂的密度不同，将LWC和SCC结合起来可能会导致严重的流动性和自密性问题。本建议的目的是研究一系列轻质自固结混凝土(LWSCC)混合料的流变性(流动特性)、力学性能、结构性能、耐久性和剪切性能。已有许多关于SCC和LWC的研究，但缺乏关于LWSCC特性的数据。因此，有必要进行理论和应用研究，以帮助开发一种将结构轻集料混凝土(减少恒载、高绝缘容量、提高耐久性、耐火和化学侵蚀)与自密实混凝土性能相结合的低密度混凝土，该性能提供良好的填充和通过能力以及高抗偏析能力。建议的LWSCC混合物将包含偏高岭土、硅灰、飞灰和/或这些的二元混合物作为辅助胶凝材料。浮石、膨胀页岩和/或人造轻骨料将被用来取代粗骨料，以减少混凝土的质量。LWSCC混合料将进行新鲜(流动性/充填能力、粘度/流动性、通过能力和抗偏析)和硬化(抗压强度)性能测试。这项研究成果--性能更好的下一代LWSCC，将扩大我们对LWSCC的了解，并对其未来在加拿大混凝土生产和建筑行业的应用产生重大影响。该计划有可能通过减少桥梁等结构的尺寸和减少材料需求而对环境产生影响，并对加拿大混凝土行业的竞争力产生影响。

Lightweight (LWC) and self-consolidating concrete (SCC) are finding widespread use in the construction industry. SCC is a highly flowable, high-performance concrete that spreads readily under its own weight without the use of vibrators and achieves the desired consolidation. LWC has been used in many different applications and is known for its performance and durability. While the economic, practical and technical benefits of both are well known, combining LWC and SCC might lead to serious problems in flowability and self-compactability due to the difference in density between lightweight aggregate and normal weight sand. The objective of this proposal is to investigate the rheological (flow characteristics), mechanical, structural, durability and shear performance of a range of lightweight self-consolidating concrete (LWSCC) mixtures. Numerous studies have been performed on SCC and LWC but there is a lack of data on the properties of LWSCC. Therefore there is a need for theoretical and applied research to help develop a LWSCC that combines the advantages of structural LWC (reduced dead loads, high insulation capacity, improved durability, resistance against fire and chemical attack) with SCC properties that offer good filling and passing ability with high segregation resistance. The LWSCC mixtures proposed will contain metakaolin, silica fume, fly ash, and/or binary blends of these as a supplementary cementing material. Pumice, expanded shale, and/or artificial lightweight aggregate will be used as a replacement of coarse aggregate in order to reduce the mass of concrete. The LWSCC mixtures will be tested for fresh (flowability/filling ability, viscosity/ flowability, passing ability, and segregation resistance) and hardened (compressive strength) properties. The research outcome - a better performing, next generation LWSCC, will expand our knowledge of LWSCC and make a significant impact on its future application in the Canadian concrete production and construction industries. The program has the potential to make impacts both on the environment through reduced size of structures such as bridges and reduced materials needs; and on the competitiveness of Canada's concrete industry.