Multi-parametric flowability classification of self-compacting concrete containing sustainable raw materials: An approach to real applications

Adding sustainable raw materials to Self-Compacting Concrete (SCC) modifies its flowability behavior. Furthermore, the use of these raw materials may at the same time even improve one fresh property while worsening another. An accurate flowability description of SCC containing sustainable raw materials therefore requires a multi-parametric classification that simultaneously covers all fresh properties (slump flow, viscosity, and blocking ratio) for an accurate description of its potential applications. Existing classifications consider each fresh property independently. In this paper, a multi-parametric flowability classification of SCC containing sustainable raw materials is proposed. The effects of multiple sustainable raw materials on SCC flowability are compiled in a dataset serving as a knowledge base with information on 663 SCC mixes containing sustainable aggregates and binders. The statistical analysis of the dataset led to the definition of three types of flowability zones. Firstly, the overall-flowability zones, in which SCC flowability is described in absolute terms: the better the in-fresh properties, the better the overall-flowability zone. Secondly, the flowability-balance zones reflect the balance between free flow (slump flow and slump-flow viscosity) and flow around obstacles (V-funnel emptying time and L-box blocking ratio). Finally, SCC is classified within flowability-predominance zones, which define the main characteristic of SCC flowability, rate of flow (viscosity) or uniformity of flow (spreading). The variability of the effect of each sustainable raw material on the flowability of SCC makes this classification useful, in so far as it offers a complete picture of the fresh behavior of SCC in which all fresh properties are simultaneously considered. Furthermore, based on the description in the proposed classification of overall flowability and the balance between free flow and flow around obstacles, the application fields are defined for which the use of each SCC mix with sustainable raw materials is recommended.