Studies on the mechanical properties of rubber concrete reinforced with high-temperature stirred pretreated waste rubber particles.

Using waste rubber particles to replace fine aggregates in the production of rubber concrete not only promotes the recycling of waste rubber but also reduces the consumption of natural sand. The difference in bonding interfaces between waste rubber particles and the concrete matrix leads to a loss of concrete strength, which has prompted many researchers to investigate surface pretreatment methods for waste rubber particles. However, these studies have been limited by low production efficiency, inconspicuous strength enhancement, and the generation of chemical waste. This study proposes a new method of pretreating waste rubber particles through high-temperature mixing, with temperature (100°C, 150°C, 200°C, 250°C, 300°C) and mixing time (15 minutes, 30 minutes, 45 minutes) as variables. The treated waste rubber particles were then subjected to thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray (EDS), and water contact angle (WCA) tests.The results show that, compared to untreated waste rubber particles, the waste rubber particles after high-temperature stirring pretreatment form a hard oxide film on the surface under high-temperature oxidation, which enhances the elastic modulus of the particles. At the same time, surface small molecular organic compounds and loose impurities are removed under the effects of stirring and friction, greatly improving the surface cleanliness.The mechanical properties of rubber concrete prepared with high-temperature stirred pretreated waste rubber particles show an initial increase followed by a decrease with the rise of temperature.In comparison, rubber concrete prepared with pretreated waste rubber particles (Stirred for 30 minutes at 250°C) shows a 38.58 % increase in cubic compressive strength, a 67.79 % increase in shear strength, a 44.45 % increase in axial compressive strength, and a 38.06 % increase in static compressive elastic modulus after 28 days of curing, compared to rubber concrete prepared with untreated waste rubber particles. • We had pretreated scrap rubber with heat stirring to boost rubber concrete strength. • We had proposed a mechanism for oxide film formation on scrap rubber surfaces. • Heating from 100℃ to 250℃ had improved rubber concrete's interfacial bonding. • Heated from 100℃ to 250℃, rubber concrete's mechanics had steadily improved. • The high-temperature stirring pretreatment process had been simple and effective. [ABSTRACT FROM AUTHOR]