La conception des bétons fluides à rhéologie adaptée (BFRA) à haute performance, notamment le béton autoplaçant (BAP), nécessite une optimisation du système cimentaire composé et des adjuvants compatibles. Ceci est nécessaire pour améliorer la rhéologie, faciliter la mise en place et la pompabilité, mais aussi réduire la pression latérale exercée sur les coffrages et améliorer la qualité de surface des éléments en béton. Cette étude vise le développement d’une approche de formulation multiéchelles afin de mieux maitriser la rhéologie des BFRA. En utilisant les indices de Carr, une méthode innovante a été proposée pour déterminer les caractéristiques rhéophysiques des poudres cimentaires sèches. La connaissance de ces propriétés a permis d’identifier les propriétés rhéophysiques clés des poudres affectant leur comportement dans les suspensions, mais aussi la rhéologie de la matrice. Ainsi, différents systèmes cimentaires composés sont optimisés et leur comportement rhéologique est validé dans des suspensions inertes et réactives. Ceci a permis de dissocier, pour la première fois, les effets physiques et chimiques des poudres sur la rhéologie des suspensions cimentaires. Par ailleurs, l’étude a mis en évidence l’existence des interactions physico-chimiques complexes entre les particules multipolydispersées en présence des polymères dispersants. De plus, l’exploitation des modèles théoriques et empiriques a permis d’identifier l’effet des caractéristiques morphologiques des poudres sur la rhéologie de la suspension. Les systèmes cimentaires optimisés sont validés à l’échelle de béton et les résultats obtenus montrent qu’ils répondent adéquatement aux exigences rhéologiques et mécaniques des BAP selon les normes en vigueur. ; Abstract : The number of structures using high-performance concrete (HPC), including self-consolidating concrete (SCC), has been increasing from year to year and became essential in construction industry, especially in North America. SCC was developed initially to ensure proper consolidation in several applications where durability and service life were the main concern of the industry. For adequate filling of restricted areas and high surface quality, SCC was used in concrete repair applications (e.g.: bridge abutments and pier caps, retaining walls, tunnel sections, etc.), precast and cast-in- place residential applications. However, the biggest challenge is to maintain a highly flowable and non-segregating concrete, hence it can spread into place, fill the formwork, and properly encapsulates reinforcement without any mechanical consolidation. The key for this balance is through an adequate control of its rheology. The performances of the flowable concrete relies on the fundamental understanding of its flow behavior. This study is one of the main themes of the NSERC Industrial Research Chair on Development of Flowable Concrete with Adapted Rheology (FCAR). The design of different types of FCAR requires more knowledge on their rheological behavior, which affects the placement method, resistance to segregation, pumpability, formwork pressure, and surface quality. The main objective of this study is to evaluate the physio-chemical characteristics of cement, supplementary cementitious materials (SCM), and alternative binders, and evaluate their effects and their interactions with admixtures on the properties of different types of FCAR. Limited knowledge exists on the potential benefits of these materials in very flowable matrices, especially in the case of moderate water-to-binder ratios (w/b) that incorporate superplasticizers (SPs). It has been found that the performance of blending cementitious matrices is a function of their synergetic effect. At the powder scale, classical parameters, including particle-size distribution, fineness, and morphology of powder used in flowable concrete greatly affect their flow behavior in suspension. An experimental investigation was undertaken to determine the physical characteristics of dry cementitious binders using Carr measurements and evaluate their coupled effects on rheology of cement-based suspensions. Cement, glass pozzolans, limestone filler, fly ash-F, and ground granulated blast-furnace slag were investigated. New Carr measurements, including the angles of repose, fall, and spatula, compressibility, and cohesion, are introduced. The experimental results showed that dry flowability of blended systems are correlated to their particle-size distribution, Blaine specific surface area, morphological characteristics, packing density, specific gravity, and cohesion. The mean average diameter, fineness, and morphological properties showed the most significant effects on dry flowability of the investigated dry powders. On the other hand, the yield stress and plastic viscosity values of the suspensions were found in good agreements with the Carr’s angles and dispersion indicators of the investigated systems. Selected ternary systems are, therefore, chosen based on their dry flowability improvement of the general use cement and the industrial conventional ternary cement. At the inert suspension scale, as particle-liquid interaction, the flowability of blended-cementitious suspensions depends on the physical properties as well as packing of solid particles. These coupled physical effects of various single and blended cementitious materials on the flow behavior of inert suspensions was evaluated. The blending effect on the wet packing and flowability of the investigated systems was highlighted. The overall dry flowability of the single powders and blended systems depends on the angles of repose (αF) and spatula (αS), which reflect their specific surface area. The dry physical parameters were in good agreement with their performance in suspension. The decrease of angles of repose and spatula resulted in higher maximum wet packing. All the investigated single powders showed higher relative alcohol demand and lower wet density than GU cement. The dry packing, morphology, and cohesion of blended cementitious materials influenced the minimum and relative liquid demand. Particles with higher aspect ratio and lower circularity increased the alcohol demand to initiate the flow of suspensions. Powders with higher angle values exhibited lower flowability. Good correlations were established to evaluate the coupled effects of different physical characteristics of powders on the wet packing of suspensions. Higher wet packing of single and blended systems having coarser average diameter values can be achieved by simultaneously reducing their compressibility and average diameter-to-fineness (d502/SSA) ratio values. In deep, the study carried on development of rheological models for these selected binary and ternary systems for various solid fraction in alcohol suspensions. Theoretical and empirical models unveiled the complexity in describing the effect of morphological characteristics of powders on the rheology of suspension. Viscosity of suspensions proportioned with different liquid-to-binder ratios was investigated. Krieger - Dougherty and Mooney models were employed to predict the relative viscosity of the investigated suspensions considering the coupled physical characteristics and relative solid fraction of dry powders. The obtained test results showed that the intrinsic viscosity (η) and coefficient kE are in good agreement not only with morphological factors, but also with the new proposed particle-size indices, including particle-size ratio (d502/SSA) and fineness index (SSA × Gs). The existing models were modified to capture the new coupled-physical parameters, such as static (αR × αS), dynamic (αF × cohesion), and total flowability (ftotal) indices. The proposed models showed high prediction accuracy to describe the viscosity of concentrated cement suspensions. At the paste scale, in fact, not only physical but competitive physico-chemical interactions exist between multi polydisperse particles used in cementitious systems to proportion self-consolidating concrete. After the success of selecting the best dry-flowable ternary systems through the rheo-blending method of dry powders in predicting their rheology in a wet inert state, this study discusses the dominant contribution for each category of powders. At water-to-binder ratios of 0.40 and 0.50, and the presence of superplasticizers, including a poly-naphthalene sulphonates (PNS) and poly-carboxylates (PC), the rheological properties of blended paste mixtures, including yield stress and viscosity, were evaluated. The experimental results showed that their dry flowability, reflecting particle size, shape, and cohesion coupled effects, justified their yield value and plastic viscosity variations, especially for glass pozzolans with high alkali content. Based on the fundamental rheo physico-chemical understanding, the ternary blends with either slag or glass pozzolan enhanced the structuration kinetics of the investigated mixtures. The physico-chemical rheological method was therefore designed in terms of new competitive insights in order to predict the adequate rheology of the SCC application. In parallel, the viscoelastic properties and the build-up kinetics of cement-based mixtures are evaluated in this study as well. These mixtures correspond to those used to design SCC. Different blended binary and ternary paste mixtures were investigated. The viscoelastic properties of these systems in terms of their build-up kinetics and dispersion were evaluated. The investigated mixtures are proportioned with two different water-to-binder ratios (w/b) of 0.40 and 0.50, and two different types of superplasticizers, including poly-naphthalene sulphonates (PNS) and poly-carboxylates (PC). The maximum rigidity, rigidification rate, percolation time, and build-up index were evaluated. Based on the fundamental physico-chemical understanding, the ternary blends with either slag or glass pozzolan enhanced the structuration kinetics of the investigated mixtures. The build-up index was evaluated as a function of particle-size (SSA × Gs) and shape factor (AR × R), as well as cohesion of the particle-particle systems. The obtained results revealed that the maximum rigidification of the investigated mixtures as well as the shape factor and cohesion in the presence of dispersants were found in good agreement with the early compressive strength. At the concrete level, in comparison to conventional industrial blended binder, at a water-to-binder ratio of 0.40 and an adequate dosage of polycarboxylate superplasticizers, the three best ternary cementitious blends were validated in terms of the workability, rheological properties, and compressive strength of SCC for repair. These ternary blends incorporated GU cement blended with coarse glass pozzolan and fine limestone fillers, or fly ash F and fine glass pozzolans, or slag and fine glass pozzolans. The workability tests included slump flow, flow time (T50), j-ring test, L-box test, and rheological measurements, including yield stress and plastic viscosity, as well as compression at 1, 7, 28, and 56 days were evaluated. Moreover, after various trials, the three best-optimized blends were selected to improve the performance of SCC in terms of workability, rheology, and compressive strength development in comparison with the conventional ternary blend. These ternary blends were already selected from the perspective of their rheo physico-chemical synergy with the superplasticizers at a given water-to-binder ratio of 0.40, but up to the paste level. The results showed that the superplasticizer dosages for each concrete were identified by the physical properties of the ternary blends, especially their fineness Blaine index (SSA × Gs), and their total dry flowability and cohesion. Depending on the roughness and the packing of the dry binders, the flow time was attributed to the packing-morphological identification, where all the investigated blends improved the stability of the conventional blend. Rheological parameters were directly dependent on the cohesion and total dry flowability of the overall particles. Therefore, considering the systematic outcomes from dry blended powder to the concrete level, this study succeeded in formulating different blended powder systems, including cement, SCMs, new alternative binders, and fillers compatible with admixtures to meet the rheological requirements of SCC, through the physico-chemical synergy of its components.