Development of Sustainable Perspective of Carbon Fibers Recycling and Reusing for Construction Materials

The development of sustainable methods is a demanding challenge posed by Global civilizations for improving the life quality in many ways. A key role in achieving sustainability goals could be the implementation of the new building materials models for the future environmental requirements. The presented process deals with the recycling of carbon fibers wastes deriving from automotive industry and the reusing within a building system, increasing in value the approach of circular economy and providing a solution to many negative economic and environmental impacts. To quantify potential benefits, in this work the behavior of cement-matrix composites containing short carbon fibers is described. An experimental campaign, starting from a specific surface treatment of the “pre peg” composite material sheets and an accurate study of the dimensional distribution of the carbon fibers, is presented. The aim is the evaluation of the influence of the percentage and length of fibers usage on the mechanical performance of cement based carbon fibers-reinforced mortars, following different approaches of mixture. The results show a good increase in stiffness and in flexural strength up to 11% and 20% respectively, for the samples characterized by fibers in percentage of 6.4% by volume of mixture and of 2–5 mm length and by a reduced amount of cement. A strong connection between the mixture workability and fibers size is observed. Finally, the assessment of the entire life cycle of the product is discussed for quantifying effective environmental impacts.