An experimental study on the post-cracking behaviour of Hybrid Industrial/Recycled Steel Fibre-Reinforced Concrete

This paper investigates the mechanical behaviour of FRC made with both Industrial and Recycled Steel Fibres recovered from waste tyres. Specimens of various mixtures, characterised by the same volume fraction of fibres, but different proportions of industrial and recycled reinforcement were tested both in compression and bending. The results highlighted a fairly negligible influence of fibres in terms of compressive strength, whereas a significant decay in the post-cracking behaviour was observed in specimens with higher fractions of recycled fibres. However, a significant enhancement in the bending response was observed with respect to the case of plain concrete, even for specimens reinforced by recycled fibres only

Studio sperimentale sulle proprietà meccaniche di calcestruzzi rinforzati con fibre metalliche riciclate

In the last decade, sustainability has become one of the key drivers in any human activity and industrial process. Being characterised by a significant demand of raw materials and energy, the construction sector is fully concerned by the challenge of reducing the environmental impact for preserving the limited natural resources employed for producing construction materials. As part of this widespread effort, the present paper deals with the possible use of Recycled Steel Fibers (RSFs) in the production of Fiber-Reinforced Concrete (FRC). Particularly, it investigates the mechanical behaviour of FRCs made with both industrial and recycled steel fibers, the latter being obtained from waste pneumatic tyres. Particularly, it is aimed at quantifying the expected decay in terms of post-cracking toughness induced by the substitution of increasing amounts of the former with an equal quantity of the latter. Therefore, an experimental campaign was carried out at the Laboratory of Materials testing and Structures (LMS) of the University of Salerno (Italy): specimens of four different mixtures, characterised by the same nominal amount of fibers and different relative proportions of the two kinds of fibers under consideration, were tested both in compression and four-point bending. As expected, no significant influence of fibers emerged in terms of compressive strength, whereas a significant decay of the post-cracking behaviour was observed for higher replacement ratio of RSFs. Particularly, a significant enhancement of the response in bending was generally observed with respect to reference plain concrete specimens, even in the case of all RSF replacement. Further investigations, both experimental and theoretical in nature, are encouraged by the results reported in this paper which is intended as a first contribution to pave the way towards understanding, controlling and predicting the behaviour of concrete with recycled fibers

Hormigón con agregados reciclados para ser utilizado como hormigón estructural

Este trabajo es acerca de Hormigón con Agregados Reciclados (RAC) en el cual una parte o la totalidad de los agregados gruesos naturales son reemplazados por agregados reciclados obtenidos a partir de hormigón endurecido triturado. La utilización de este material favorece la preservación de canteras naturales reduciendo el consumo de energía asociado al proceso de explotación pero además, permite reutilizar hormigón de desecho. Los agregados de hormigón reciclado poseen una mayor porosidad que los naturales la cual produce una degradación en las propiedades elásticas y resistentes del hormigón en comparación con aquellas de hormigón estándar. En este trabajo se presentan los resultados de una amplia campaña experimental desarrollada en las universidades de Salerno, Italia y de Buenos Aires, Argentina, con el objeto de identificar las propiedades fundamentales del material y los parámetros a tener en cuenta en la modelación constitutiva del mismo. Luego, se muestran las conclusiones a las que se arribó en base al análisis de los resultados experimentales y algunas recomendaciones a tener en cuenta para poder utilizar este material como hormigón estructural