In modern asphalt mix design, the use of high-quality asphalt additives has become essential to improve performance, sustainability, and long-term durability. Whether the goal is to incorporate higher amounts of Reclaimed Asphalt Pavement (RAP), reduce production and compaction temperatures, or optimize polymer-modified bitumen (PMB) blends, additives can help producers achieve these objectives without compromising pavement life. Sripath has developed a suite of innovative additives including ReLIXER®, PGXpand®, and ButaPhalt® that demonstrate measurable benefits across global roadway and roofing applications.
Unlocking the Benefits of Asphalt Additives
Asphalt additives developed by Sripath offer multiple advantages that directly enhance mix performance and longevity:
- Increased RAP Utilization: Traditional mixes often limit RAP to 20-30% due to concerns over aging and binder compatibility. Additives like ReLIXER rejuvenate aged binder allow high-RAP content of 30-100% while maintaining functional properties. This can reduce costs and support sustainable construction practices by reusing materials while retaining long-term performance.
- Improved Binder Performance: Asphalt additives such as PGXpand enhance high temperature PMB properties while anchoring low temperature properties. This can help ensure the asphalt can resist rutting in hot climates while maintaining native flexibility in colder conditions.
- Optimized PMB Blends: Crosslinking additives like ButaPhalt can help optimize the viscoelastic and stability properties of PMB blends. These modified binders can maintain their intended performance and give producers confidence in durability.
Proven RAP Performance with ReLIXER
ReLIXER has been extensively tested and used in pavements worldwide, demonstrating the ability of rejuvenate aged asphalt to maintain durability across various climates and binder types. For example:
- Illinois Tollway, USA: 40% RAP + ReLIXER with regular binder
- City of Gold Coast, Australia: 40% RAP + ReLIXER with PMB binder
- Dublin, Ireland: 60% RAP + ReLIXER with regular binder
- New York City, USA: 100% RAP + ReLIXER with no additional binder
Laboratory testing and field trials have confirmed that properly rejuvenated mixes provide equivalent fracture toughness and aging performance compared to low-RAP or no-RAP mixes, even after extended aging. This allows for cost-effective high-RAP applications while ensuring long-term roadway durability.
Enhanced Binder Properties with PGXpand
Bitumen-friendly additives like PGXpand help optimize binder properties across a wide temperature range. Key findings include:
- Increasing PGXpand content raises the softening point and improves high-temperature performance while maintaining low-temperature flexibility.
- Storage stability tests show minimal top-to-bottom differences in the binder after holding at elevated temperatures, demonstrating superior thermal properties.
- In practice, PGXpand enables consistent PMB properties for applications ranging from heavy-traffic roadways to durable roofing systems.
By improving binder performance, PGXpand can help reduce the risk of rutting, cracking, and premature failure to support longer-lasting asphalt roadway pavements.
For roofing applications, PGXpand helps optimize binder and membrane properties across a wide temperature range. PGXpand improves the performance of bitumen membranes by raising the softening point without sacrificing tack, adjusting penetration characteristics for better mechanical behavior, and lowering viscosity in filled compounds for easier handling. It enhances seam welding and tack, permits higher filler loading, and increases formulation flexibility, all while maintaining excellent storage stability and compatibility with SBS and a range of bitumen types.
In testing, roofing compounds with PGXpand showed higher softening points, improved peel strength, and nearly three times more WOM cycles before failure, demonstrating both superior field performance and enhanced manufacturability.
ButaPhalt and PMB Crosslinking
ButaPhalt is a specially formulated crosslinking additive designed to improve PMB blend performance. Testing results highlight:
- Enhanced G/sinδ values* at elevated temperatures, improving bitumen high temperature grade, many times with reduced SBS contents
- Improved MSCR performance at 64°C, 70°C, and 76°C, indicating superior elastic recovery and long-term resilience
- Stable PMB properties after extended aging periods (2-20 hours)
- Lower hydrogen sulfide emissions during PMB production
These benefits allow engineers and producers to use modified binders with increased confidence while achieving more consistent performance.
Real-World Applications and Global Impact with Sripath
Sripath additives have been successfully applied in diverse regions, demonstrating their adaptability and benefits across different products and applications:
ReLIXER: High-RAP Roadway Mixes (Select Examples)
- Australia: 40-100% RAP mixes in Brisbane, Gold Coast, and New South Wales
- United Kingdom: 50% RAP mixes in England
- United States: 40-100% RAP projects in Illinois, New Jersey, Virginia, and New York City
- India: 50% high-RAP base courses
PGXpand: Enhanced PMB and Roofing Performance
- Roadway surfaces: VG-30 highway blends with PGXpand in India showed improved rutting resistance with a softening point increase from 64.1°C to 84°C and maintained low penetration for flexibility.
- Roofing membranes: Higher softening points, improved peel strength, and threefold increase in WOM cycles before failure, enhancing durability and manufacturability
ButaPhalt: Improved PMB Productivity and Stability
- Manufacturing trials with PG64 binder + 3-5% SBS showed reduced reaction times when ButaPhalt was used, improving production efficiency.
- Crosslinking benefits allow consistent PMB properties, enhanced elastic recovery, and long-term resilience in roadway applications.
By enabling higher RAP utilization, better PMB and roofing performance, and optimized production efficiency, these additives help reduce environmental impact, improve worker safety, and extend the lifespan of pavements and membranes globally.
Sripath Asphalt Additives: Long-Term Durability for Roadways and Roofing
The integration of asphalt additives such as ReLIXER, PGXpand, and ButaPhalt allows producers to create durable, high-performing asphalt mixtures while supporting sustainability goals. By enabling higher RAP content, improving binder properties, and optimizing PMB performance, these additives ensure long-term durability for roadways and roofing applications worldwide. For engineers and contractors seeking cost-effective and reliable solutions, Sripath additives offer a proven path to enhanced performance without compromise.
For more information about asphalt additives from Sripath, contact info@sripath.com.
