# Activation Efficiency and Restoration Effects of SBS Network-Repairing Regenerators on Aged Asphalt

## TL;DR

A new regenerant with epoxy groups can restore aged asphalt by repairing polymer networks, improving its performance at different temperatures.

## Contribution

A novel epoxy-group-containing regenerant is shown to effectively restore aged SBS-modified asphalt by repairing its polymer network structure.

## Key findings

- Regenerants with epoxy groups can restore fractured polymer chains in aged SBS-modified asphalt.
- The regenerant improves high and low-temperature performance and viscoelastic properties of recycled asphalt.
- An 8% dosage of the regenerant provides optimal repair of the SBS cross-linked network.

## Abstract

What are the main findings?
Regenerants containing epoxy groups can effectively restore the fractured polymer chains of SBS following thermal-oxidative aging.The high and low-temperature performance of the recycled asphalt has been improved following the restoration of the fractured SBS polymer chains during aging.This regenerant is capable of restoring the viscoelastic properties of aged asphalt.Compared with commercially available regenerants, this regenerant exhibits a superior penetration effect.

Regenerants containing epoxy groups can effectively restore the fractured polymer chains of SBS following thermal-oxidative aging.

The high and low-temperature performance of the recycled asphalt has been improved following the restoration of the fractured SBS polymer chains during aging.

This regenerant is capable of restoring the viscoelastic properties of aged asphalt.

Compared with commercially available regenerants, this regenerant exhibits a superior penetration effect.

What are the implications of the main findings?
The recoverable aging of the SBS network structure indicates that the reclaimed asphalt pavement (RAP) from SBS-modified asphalt pavements can be reused in the original pavement or in high-performance layers requiring SBS-modified asphalt, without necessitating downgraded application.Improved permeability enables a greater quantity of regenerant to penetrate into aged SBS-modified asphalt during actual construction, thereby facilitating more extensive restoration of the degraded SBS modifier and significantly enhancing the performance of the recycled asphalt.

The recoverable aging of the SBS network structure indicates that the reclaimed asphalt pavement (RAP) from SBS-modified asphalt pavements can be reused in the original pavement or in high-performance layers requiring SBS-modified asphalt, without necessitating downgraded application.

Improved permeability enables a greater quantity of regenerant to penetrate into aged SBS-modified asphalt during actual construction, thereby facilitating more extensive restoration of the degraded SBS modifier and significantly enhancing the performance of the recycled asphalt.

Although extensive research has been conducted on the regenerants for unmodified and SBS-modified asphalt, in-depth studies on the activation of regenerants to restore the SBS cross-linked network while preserving their diffusion performance have not yet been reported. This study quantitatively evaluated the activation effect of self-healing regenerants on SBS cross-linked networks by testing the activation degree of 6%, 8%, and 10% cross-linked networks with self-healing regenerants; the phase structure of SBS-modified asphalt before and after regeneration was examined using fluorescence microscopy (FM); the underlying mechanism of the reactive regenerant was elucidated by Fourier Transform Infrared Spectroscopy (FTIR) and Gel Permeation Chromatography (GPC); furthermore, the rheological response characteristics of the reactive regenerant and conventional regenerant were comparatively analyzed. The findings indicated that the SBS cross-linked network self-healing regenerant exhibited a more pronounced activation effect on aged asphalt. Specifically, when the dosage of the regenerant reaches 8%, its repairing effect on the cross-linked network becomes particularly significant. Reconstructing the cross-linked network structure of SBS-modified asphalt enabled the recovery of the viscoelastic properties of the recycled asphalt. Nevertheless, an excessive dosage of the regenerant failed to further enhance the cross-linked structure in a meaningful way and might even exert an adverse impact on the high-temperature performance of the recycled asphalt.