Influence of nano silica and crumb rubber on the physical and durability characteristics of concrete

The global challenge of waste tire disposal poses a significant environmental threat, driving exploration into sustainable solutions. The study investigates rubberized concrete (RC) as a promising method to repurpose discarded tires, incorporating recycled rubber aggregates (RA). The aim is to reduce waste and address tire waste accumulation. To enhance RC properties, nano silica (NS) is introduced, exploring its impact on the interplay between rubber content and concrete durability. Despite advancements in concrete enhancement through nanomaterials, significant research is not done to understand the behaviour of NS-treated RC. The investigation varies rubber content (5, 10, and 15%) and NS incorporation (0–3%) for sustainability and structural integrity. The mixing process ensures proper integration of components, including natural aggregates (NA), rubber particles, and NS. Specimens undergo testing to evaluate RC's physical properties and durability. The experiment showed the best results when using a composition consisting of 5% rubber and 3% nano-silica. This particular combination resulted in a reduction of 20.95% in workability and 4.94% in density of the concrete. The acid resistance test resulted in a mass loss of 4.8% and a compressive strength loss of 6% after 28 days when exposed to H₂SO₄. When exposed to HCl, the mass loss was 0.7% and the compressive strength loss was 6.6%. The RCPT value experiences a decrease of 10.34%, while the sorptivity value undergoes a decrease of 3.49%. Life cycle assessment (LCA) study showed that when RA increases CO2, NS reduces it; combining at 3% NS yields CO₂ reductions, emphasizing environmental benefits. The research aims to optimize RC properties, impacting the construction industry's need for alternative aggregates while addressing tire waste's environmental impact.