Design of Self Compacting Concrete for Durability of Prescriptive vs. Performance-Based Specifications

摘要

At the beginning of 2000, a research and development program was begun to design and produce SCC using ternary blended cements with further additions of ground granulated blast furnace slag (GGBFS), silica fume or limestone filler, leading to the production and use of SCC in construction by 2001. SCC from actual construction works were evaluated, in fresh and hardened state, aimed at determining their compressive strength and some durability associated parameters, such as air permeability, chloride penetrability and sorptivity. SCC showed at least similar durability-related performance as compared to conventional concrete with similar compressive strength, although the latter had equal or lower W/C and higher cement content. Moreover, the special properties of the self-compacting concrete in the fresh state may lead to a significant reduction of compaction defects, thus improving the overall durability of the structure. The applicability of Codes and standards that impose limits for the W/C on a prescriptive basis for durability come into question. These limits should consider the actual durability related properties of SCC that show better performance than conventional concrete for a given W/C or cement content. Performance-related Codes could be more appropriate if they take into account the actual behaviour of this new concrete.