Performance investigation of ecoconcrete with recycled aggregates enhanced by nanoparticles

Abstract

In the context of sustainable development and the urgent need to reduce the environmental footprint of the construction industry, the reuse of recycled concrete waste in mortar formulations has emerged as a promising strategy. However, the incorporation of such waste materials typically leads to diminished mechanical performance, primarily due to the reduced chemical activity of the recycled aggregates. To address this drawback, nanoparticles have gained attention as functional additives capable of restoring or even enhancing the structural integrity of cement-based composites. This preliminary study investigates the effect of two types of nanoparticles, Nano-Silica Powder and Multi-Walled Carbon Nanotubes on the mechanical properties of mortars incorporating recycled concrete waste at two different dosages. The prepared specimens were subjected to standardized compressive strength and flexural tensile strength tests to evaluate the reinforcing effects and variability induced by these nanomaterials. Experimental results demonstrated a significant improvement in compressive strength, particularly in mixtures containing nano-silica, which can be attributed to its pozzolanic activity, filler effect, and refinement of the pore structure. In contrast, flexural strength results exhibited considerable variability, likely stemming from challenges in achieving homogeneous nanoparticle dispersion and the complex interactions between nanoparticles and the cementitious matrix. Beyond their physical and chemical contributions, nanoparticles exhibit behaviors that stem from quantum-scale phenomena, including quantum confinement, surface energy effects, and tunneling. These characteristics, while not yet fully understood in the context of cementitious materials, are believed to play a role in modifying the hydration kinetics and bonding mechanisms at the nanoscale. Such effects open new avenues for manipulating material behavior at a fundamental level. The findings of this study suggest that nanoparticles can act as effective reinforcement agents in ecoconcrete, providing a pathway to partially or fully recover the mechanical properties lost due to the use of recycled components. This work provides a foundational basis for future research that aims to leverage nanotechnology and, potentially, quantum-scale interactions to engineer sustainable and high-performance construction materials.