# From Pre-Swelling to Performance Enhancement: Mechanisms and Effects of an Instant Ultra High-Performance Bituminous Material Modifier

## TL;DR

A new method for making high-performance bitumen is shown to be as effective as traditional methods but much faster and simpler.

## Contribution

The study introduces an instant ultra-high-performance bitumen modifier (SHVE-M) that achieves wet-process performance with a simplified preparation method.

## Key findings

- SHVE-MB requires only 10 minutes of shearing and matches the performance of traditional wet-process bitumen.
- SHVE-MB exhibits excellent viscoelastic properties and pavement performance comparable to conventional high-viscosity modified bitumen.
- The modifier forms a stable bitumen-polymer spherical structure with a large molecular size content of 43%.

## Abstract

What are the main findings?
Pre-swelling via 120 min shearing with 3 h maturation forms a distinct bitumen-polymer spherical structure.SHVE-MB preparation is highly efficient, requiring only 10 min shearing without extra swelling or maturation.The bituminous material prepared by SHVE-M exhibits performance equivalent to that of wet-process.

Pre-swelling via 120 min shearing with 3 h maturation forms a distinct bitumen-polymer spherical structure.

SHVE-MB preparation is highly efficient, requiring only 10 min shearing without extra swelling or maturation.

The bituminous material prepared by SHVE-M exhibits performance equivalent to that of wet-process.

What are the implications of the main findings?
The proposed method significantly simplifies the production process of high-performance modified bitumen.It effectively bridges the performance gap between instant and traditional wet-process modified bitumen.The findings provide a more time-efficient and robust solution for road engineering materials.

The proposed method significantly simplifies the production process of high-performance modified bitumen.

It effectively bridges the performance gap between instant and traditional wet-process modified bitumen.

The findings provide a more time-efficient and robust solution for road engineering materials.

To elucidate the modification and pre-swelling mechanisms of instant bituminous modifiers and their contribution to bituminous materials’ performance, this study investigates an instant ultra-high-performance bitumen modifier (SHVE-M). Fluorescence microscopy (FM), gel permeation chromatography (GPC), physical property tests, viscoelastic properties tests, dynamic shear rheometer (DSR), and mixture pavement performance tests were employed to systematically characterise the instant modified bitumen (SHVE-MB) and its mixture (SHVE-MBM). The results indicate that SHVE-M forms a stable “bitumen phase–polymer spherical phase” structure. ImageJ-win64 analysis revealed that SHVE-M exhibits a modifier area fraction of 46.68% and an average area fraction of 0.22‰, while SHVE-MB achieves a modifier area fraction of 17.54% and an average area fraction of 0.18‰. This morphology is supported by a large molecular size (LMS) content of 43% in SHVE-M. In terms of physical properties, the SHVE-MB (prepared via 10 min shearing) exhibited a penetration of 46.2 dmm, a softening point of 91.7 °C, and a ductility of 34.3 cm. These values are highly comparable to the conventional wet-process HVE-MB (prepared via 4 h maturation), with negligible differences of 0.5 dmm, 1.7 °C, and 1.4 cm, respectively. Quantitatively for viscoelasticity, SHVE-MB achieved a dynamic viscosity of 425,283.4 Pa·s at 60 °C and an elastic recovery rate of 92.1%, paralleling the 414,623.7 Pa·s and 93.6% of HVE-MB. Regarding mixture performance, the high-temperature dynamic stability (DS) of SHVE-MBM reached 7974 times/mm, approaching the 8256 times/mm of HVE-MBM. The water stability was excellent with a splitting tensile strength ratio (TSR) of 97.4% (vs. 98.0% for HVE-MBM). Furthermore, the low-temperature fracture toughness (KIC) reached 39.8 N/mm1.5, significantly outperforming SBS-MBM (27.9 N/mm1.5) and remaining close to HVE-MBM (43.9 N/mm1.5). These findings indicate that SHVE-MB effectively bridges the performance gap between instant and traditional high-viscosity modified bitumen, and the pre-swelling mechanism of SHVE-M is well characterized in this study.