INSTANTANEOUS AND TIME-DEPENDENT BEHAVIOUR OF REINFORCED SELF-COMPACTING CONCRETE SLABS

摘要

One of the developments in concrete technology is Self-Compacting Concrete (SCC). SCC refers to highly floivable, non-segregating concrete that can be spread into place, /illthe formwork, unci encapsulate the reinforcement without the aid of any mechanical consolidation. In this study, cracking in reinforced SCC and Fibre Reinforced Self-Compacting Concrete (FRSCC) slabs with particular emphasis on the development of flexural cracking have been investigated both experimentally and analytically. Two series of tests were conducted on the one-way reinforced SCC and FRSCC slabs to study the development of short-term and long-term flexural cracking under monotonically increasing loads and caused by the combined effects of constant sustained service loads and shrinkage, respectively. Defections, crack patterns, crack widths, steel strains and concrete surface strains at the steel level were recorded in the instantaneous cracking and post-cracking range for short-term tests and both immediately after loading and up to 240 days under sustained loads for long-term tests. Analytical models were developed to simulate SCC and FRSCC instantaneous and time-dependent flexural cracking. Also, available tension chord models for CC ami IRC were modified and used in the proposed model to study the SCC and FRSCC tension zone of a flexural member and the effect of creep and shrinkage with time. Moreover, the crack width and spacing calculation procedures of the available codes of practice were assessed and some deficiencies in the existing approaches exposed. Finally, a comprehensive parametric study for the instantaneous and time-dependent behaviour of the slabs by FEM analyses has been conducted.