Experimental investigation and numerical modelling of macro-synthetic fibre reinforced concrete materials

Fibre Reinforced Concretes are innovative composite materials covering a plenty of structural applica-tions. The mechanical behaviour of these materials has been studied by many researchers, and many official guidelines cover their usage. Nevertherless, many aspects are still under investigation above all its long term performance and time dependent phenomena. The whole research project is aimed at un-derstanding which ascpets, that could be represented by the material properties or external factors, could affect the mechanical behaviour. The investigation is carried on by means of experimental tests on FRCs characterized by different strengths of the matrix, different fibre dosages and different fibre types. The experimental part is the starting point for the elaboration of a numerical predictive model because the prediction of the cracking mechanisms evolution typical of FRCs is the key for the design with fibre reinforced concrete materials. On the other side, the time dependent phenomena affect the behaviour and the serviceability state of the material. The time and the environmental conditions play an important role in the deformations evolution over time. In a first step, the experimental investigation is carried analysing the effect of compressive, tensile and flexural load aimed at studying the separated contribu-tions. The hetereoneneity of the concrete mixed with the discontinuity of the reinforcement need to be accounted. For this reason, based on the experimental results achieved, a numerical predictive model is going to be elaborate. It is straightforward to think that the composite nature makes necessary the char-acterization of the fibrous reinforcement, concrete matrix and their mechanical bond interaction. The present work shows a part of the entire research project. In particular, it discusses the effect of macro-synthetic fibres in cementitious matrixes analysing their short term mechanical performance. Three concrete strength classes, from 33 MPa to 55 MPa are combined with 2 kg/m3 and 4 kg/m3 of fibre dosages. The experimental results are used to calibrate a numerical predictive model based on the Lat-tice Particle Discrete Model constitutive law.