Novel cement-based sandwich composites engineered with ground waste tire rubber. Design, production, and preliminary results

The challenge of making a structure as light and eco-friendly as possible without sacrificing strength is fundamental in the current construction design. Sandwich technology is well-established in lightweight design since the separation of two thin face sheets by a lightweight core allows for outstanding excellent mechanical properties combined with a high strength-to-weight ratio. The aim of this study was to design and characterize newly developed cement-based sandwich structured composites using rubber-concrete mixes as a core layer and stiff face sheets made of ordinary concrete. It was attempted to combine the high mechanical strength and stiffness of the outer cementitious layers with the technological characteristics of the rubberized core to achieve a final product having optimized properties in terms of acoustic damping, toughness, and load-bearing capacity. The sandwiches were made by two different rubberized cores, involving the use of selected rubber particles from waste tires as a total aggregate fraction of the mix. Static and dynamic mechanical testing revealed better performance of sandwich composites in terms of flexural strength, stiffness, energy absorption, and ductility with respect to the monolithic rubberized concrete materials. Acoustic insulation test highlighted very good noise damping characteristics in the high-frequency range. The physical-mechanical characteristics of the core greatly influenced the technological behavior of sandwich samples due to the significant impact of the rubber size gradation on the rubber-concrete's characteristics. Based on the discovered performance, sandwich composites were suggested for low-load paving unit applications, combining reduced weight with satisfactory mechanical and acoustic properties.