# Mechanical and Dynamic Performance of a High-RAP Half-Warm Asphalt Polymeric Composite for Rapid Pavement Repair

## TL;DR

This study develops a high-RAP half-warm asphalt mixture with additives to enable low-temperature production while maintaining mechanical performance for pavement repair.

## Contribution

A dual-additive system enables high-RAP HWMA mixtures to be produced at low temperatures without compromising mechanical and durability performance.

## Key findings

- The optimized mixture achieved 5.84 kN Marshall stability and 80% retained stability after moisture conditioning.
- Dynamic stability reached approximately 1100 passes/mm, and stability increased from 4.50 kN at 50 °C to 9.20 kN at 90 °C.
- The dual-additive strategy stabilizes high-RAP mixtures at low production temperatures (≈60–70 °C).

## Abstract

High reclaimed asphalt pavement (RAP) half-warm mix asphalt (HWMA) mixtures provide a low-energy alternative for pavement repair but often suffer from insufficient binder activation and reduced mechanical performance at low production temperatures. This study develops a high-RAP (73.8%) half-warm repair mixture using a dual-additive system comprising a rejuvenator and a low-temperature composite additive. The mixture was designed to enable effective mixing and compaction at temperatures as low as 60 °C. The optimized formulation achieved a 5.84 kN Marshall stability, 7.0% voids in total mixture, 80% retained Marshall stability after moisture conditioning, and approximately 1100 passes/mm dynamic stability. Temperature sensitivity analysis showed that stability increased from 4.50 kN at 50 °C to 9.20 kN at 90 °C with corresponding VTM reduction from 15.2% to 4.8%. The results demonstrate that a high-RAP HWMA repair mixture can satisfy mechanical and durability requirements while being produced at substantially reduced temperatures, supporting practical and sustainable pavement maintenance applications. The study further provides mixture-scale evidence that a dual-additive strategy can stabilize high-RAP mixtures under very low half-warm production temperatures (≈60–70 °C), which are representative of rapid repair conditions and remain insufficiently investigated in existing WMA–RAP research.