# Mechanical Performance of Basalt Fiber-Reinforced Fully Recycled Concrete Using Triple-Modified Recycled Aggregates

## TL;DR

This paper introduces a triple modification method to enhance the mechanical performance of fully recycled concrete using basalt fibers and modified recycled aggregates.

## Contribution

A novel triple synergistic modification method combining calcium ion treatment, dopamine polymerization, and nanofiber reinforcement is proposed.

## Key findings

- The 28-day compressive strength of the concrete increased by 56% after modification.
- Splitting tensile strength improved by 129% due to the optimized interfacial transition zone structure.
- Microscopic analysis revealed gradient strengthening via pore filling, chemical bonding, and fiber bridging.

## Abstract

Aiming at the critical problem that recycled concrete aggregate (RCA) has more cracks and severe defects on its surface than natural aggregate, resulting in an excessively weak interfacial transition zone (ITZ) between RCA and cement paste, this paper proposes a triple synergistic modification method combining calcium ion accelerating solution treatment, dopamine polymerization treatment and nanofiber reinforcement to improve the properties of recycled aggregate. Through in-depth research on the mechanical properties of basalt fiber-reinforced fully recycled concrete after triple modification, it is found that the triple modification technology can significantly optimize the structure of the recycled aggregate-cement paste ITZ. The 28-day compressive strength of the fully recycled concrete is increased by 56% (reaching 27.7 MPa), and the splitting tensile strength is improved by 129% (reaching 5.32 MPa). Microscopic analysis shows that the modified system realizes gradient strengthening of the ITZ structure through the synergistic mechanism of “pore filling, chemical bonding and fiber bridging”. This research provides a new idea for the high-performance modification of fully recycled concrete, and has important significance for promoting the sustainable development of the construction industry.