Title:
Workability, Testing, and Performance of Self-Consolidating Concrete
Author(s):
K. H. Khayat
Publication:
Materials Journal
Volume:
96
Issue:
3
Appears on pages(s):
346-353
Keywords:
bleeding (concrete); consolidation; high-performance concrete; rheological properties; segregation; stability; viscosity; workability
DOI:
10.14359/632
Date:
5/1/1999
Abstract:
Self-consolidating concrete is a new category of high-performance concrete that exhibits a low resistance to flow to insure high fallibility and a moderate viscosity to maintain a homogeneous deformation through restricted sections, such as closely-spaced reinforcement. Self-consolidating concrete is used to improve the productivity of casting congested sections and insure the proper filling of restricted areas with minimum or no consolidation. Such concrete can improve the homogeneity of highly fellable concrete that is necessary to insure good bond development with reinforcing steel, adequate structural performance, and proper durability. This paper reviews the benefits of using self-consolidating concrete to facilitate the casting of densely reinforced sections and improve productivity and on-site working conditions. Workability requirements necessary to secure self-consolidation and the principles involved in proportioning such highly fellable concrete are discussed. Field-oriented tests are useful to evaluate the deformability, filling capacity, and stability of self-consolidating concrete are presented. The performance of concrete mixes proportioned according to two main approaches needed to insure high deformability, low risk of blockage during flow, and proper stability are compared. Such approaches involved the proportioning of concrete with moderate water-to-cementitious material ratios of 0.35 to 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.