Polymer modified bitumen (PMB) mixes are nothing new to the asphalt industry. But many traditional polymer additives for asphalt require high energy and high temperatures for blending, which can be taxing on environmental resources and production costs. Roads & Infrastructure Australia took a closer look at Sripath’s PGXpand®, a specially engineered molecule and bitumen-friendly polymer additive that works across a variety of applications. 

 

PGXpand is intentionally designed to enhance high temperature performance without affecting low temperature properties. “We wanted to create a product that could deliver roadways with outstanding rutting resistance, fatigue properties, high temperature performance, as well as durability, while also being easy to process and use,” explained Krishna Srinivasan, President, Sripath Technologies.  

 

The result is a polymer additive for asphalt that is also highly dosage efficient and can contribute to contractor sustainability efforts by lowering mixing times, energy consumption, and paving temperatures. PGXpand can be used across PMB hot mixes, hybrid PMB mixes, hot spray applications, and repair and maintenance applications. All of this can be achieved while helping contractors potentially reduce costs through dosage efficiency.  

 

Independent testing has included work by the Royal Melbourne Institute of Technology (RMIT) in Melbourne, Victoria, Australia, which has analyzed PGXpand’s performance in PMB hybrid mixes across a variety of Australian aggregates, binders, and additive blends. “This PMB can be sprayed at lower temperatures, is easier to manufacture, and shows better adhesion to aggregates,” commented Dr. Filippo Giustozzi, Associate Professor, RMIT.  

 

With Australia striving to meet a net zero emissions goal by 2050, sustainability in asphalt paving has become a more pressing issue. “Because of the lower energy requirements for using PGXpand and its compatibility with crumb rubber and other polymers in bitumen, it’s gaining traction from an environmental aspect,” explained Ravi Rajagopalan, General Manager, Sripath Asia-Pac.  

 

Read the full article to learn more about how PGXpand is being evaluated and used in the Australian paving industry.