Investigation into Recycled Rubber Aggregates and Steel Wire Fiber for Use in Concrete Subjected to Impact Loading

This study investigated the potential use of tire derived rubber aggregates, particularly powdered rubber, and recycled steel-wire fibers in concrete subjected to impact loading. The fibers are approximately 0.4 mm in average diameter and 25 mm in length on average. There are two main portions to this study. The first phase of this study involved small-scale batching to investigate the fresh and hardened properties of concrete mixtures with powdered rubber up to 50% replacement of sand volume and recycled steel fibers up to 0.25% by mixture volume. Additional mixtures containing powdered rubber, crumb rubber, and tire chips were evaluated for their mechanical performance. Based on fresh concrete properties, compressive strength, modulus of rigidity, and impact resilience, mixtures were selected for a second investigative phase. In this phase, static and impact testing were performed on two sets of scaled beams. One beam set was produced with concrete containing 40% powdered rubber as a sand replacement and another beam set with a combination mixture incorporating rubber products of varying sizes (10% powdered rubber, 10% crumb rubber, and 10% tire chip) and 0.25% recycled steel fiber. Flexural performance improved initially with the inclusion of powdered rubber but decreased with increasing concentrations. Mixtures including recycled steel fibers at 0.25% outperformed industrial steel fiber mixtures in both flexural strength and impact resistance. For both the static and impact beams with the recycled powdered rubber and steel fibers in the combination demonstrated improved load distribution and load-carrying capacity, acting as a sufficient replacement for industrial steel fiber reinforcement.

A Study of Rubber-REOB Extender to Produce Sustainable Modified Bitumens

Thanks to greater attention to the environment and the depletion of non-renewable resources, the sustainability and the circular economy have become crucial topics. The current trend of pavement engineering is to reduce the use of standard bitumen by replacing it with more sustainable materials such as industrial residues and by-products. In this regard, the present study aims to characterize innovative extended bitumen using recycled materials. Due to promising preliminary results as bitumen modifiers, the powdered rubber from end-of-life tires and the re-refined engine oil bottom (REOB) have been investigated as feasible components of bitumen extenders. Nevertheless, several variables strongly affect the performance of the resulting binder, which cannot be neglected. Hence, this research focuses on the rubber–REOB interaction in order to evaluate their optimum ratio, which may maximize the use and advantages of both recycled materials as suitable partial replacements for bitumen. Various rubber–REOB ratios were considered and investigated by means of low and high frequency nuclear magnetic resonance (NMR) spectrometers and scanning electron microscope (SEM).

Largely enhanced mechanical properties and heat distortion temperature of β-nucleated isotactic polypropylene by adding ultrafine full-vulcanized powdered rubber

Large enhancement in toughness is observed in β-iPP with a small amount of EA-UFPR, which is mainly attributed to the decreased size of supermolecular units and formation of an interconnected structure.

Mechanics and Pavement Properties Research of Nanomaterial Modified Asphalt

Nanomaterials (nano powdered rubber VP401, VP501 and sepiolite and CaCo3 composites) were selected to improve the high-temperature and low-temperature performance of asphalt binder. Nanomaterial modified asphalt was prepared using the high shear machine. Laboratory experiments of asphalt binder and asphalt mixture were conducted to evaluate the properties of modified asphalt binder, including the penetration, ductility, softening point, viscosity, and etc. Also, asphalt mixture tests were carried out, such as the cleavage strength test, resilient modulus test, rutting test, water stability test and etc. Based on the test results, asphalt binder modified by 1% nano powdered rubber VP401 has better performance resistance to low temperature crack and rutting, compared to other nanomaterial modified asphalt binder.