WORKABILITY, TESTING, AND PERFORMANCE OF SELF-CONSOLIDATING CONCRETE
WORKABILITY, TESTING, AND PERFORMANCE OF SELF-CONSOLIDATING CONCRETE
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作者：
K. Khayat
自固结混凝土（SCC）是一种新型高性能混凝土，它具有低流动阻力，可确保高流动性，并具有中等粘度，可在有限截面（如密集钢筋）内保持均匀变形。本文回顾了使用自密实混凝土的好处，以促进密集加强部分的铸造，提高生产率和现场工作条件。必要的工作性要求，以确保自我巩固和原则，在配比等高度流动性混凝土进行了讨论。现场定向测试有用的变形能力，填充能力，和SCC的稳定性进行了评估。混凝土混合物的性能进行了比较，根据两个主要的方法，以确保高变形能力，低风险的堵塞过程中流动，并适当的稳定性。这些方法包括以0.41的适度的水-胶凝材料比（w/cm）配料混凝土并使用粘度增强剂以增加稳定性，以及不使用任何粘度增强剂但具有0.35-0.38的较低w/cm的混合物以减少自由水含量并提供稳定性。混合物与中等和高含量的三元胶凝材料进行了评价。每种混凝土的性能进行了比较，与250毫米的坍落度的流动性混凝土。
Self-consolidating concrete (SCC) is a new category of high-performance concrete that exhibits a low resistance to flow to ensure high flowability and a moderate viscosity to maintain a homogeneous deformation through restricted sections, such as closely spaced reinforcement. This paper reviews the benefits of using SCC to facilitate the casting of densely reinforced sections and improve productivity and onsite working conditions. Workability requirements necessary to secure self-consolidation and the principles involved in proportioning such highly flowable concrete are discussed. Field-oriented tests useful in evaluating the deformability, filling capacity, and stability of SCC are presented. The performance of concrete mixes proportioned according to two main approaches needed to ensure high deformability, low risk of blockage during flow, and proper stability are compared. Such approaches involved the proportioning of concrete with a moderate water-to-cementitious material ratio (w/cm) of 0.41 and using a viscosity-enhancing admixture to increase stability, as well as mixes without any viscosity-enhancing admixture, but with lower w/cm of 0.35-0.38 to reduce free water content and provide stability. Mixes with both moderate and high contents of ternary cementitious materials were evaluated. The performance of each concrete was compared to that of a flowable concrete with 250-mm slump.