Correlation Between “Very Early” Age Fracture Performance and Evolution of Rheological Properties of High Performance Fiber Reinforced Cementitious Composites with Adapted Rheology

The tremendous advances in concrete technologies our society is witness of, do not only provide the construction industry with new advanced materials and processing/ manufacturing techniques, but also require the performance of cement based materials to be investigated not only in its structural service state, but also throughout its very early and early age life. Tailored successful placement and development of mechanical performance, even in the first hours of life, can affect the structural durability and discriminate about the successful accomplishment of the structural performance throughout the service life. In this paper reference is made to a High-Performance Fibre-Reinforced Cementitious Composite, formulated with adapted rheology to ease its placement and most of all to achieve a tailored alignment of the fibres through the casting flow. The development of tensile and shear fracture properties in the first hours (up to three) after the first contact between cement and water has been studied with an ad-hoc designed test set-up. The knowledge of such properties is of the utmost importance to foster the use of these kind of advanced cement based materials with adapted rheology in precast construction, where the design of transient situations, including demoulding and handling, may play a crucial role, also in the sight of optimizing the productivity. In a quality control framework, the development of tensile and shear fracture properties of the investigated materials in the considered time frame have been also correlated to the evolution of rheological properties, so far evaluated through a mini-slump flow tests