Polymer Modified Membranes have a long history in the roofing and building materials industries. In addition to improving high temperature properties, they provide superior crack resistance, particularly in cold conditions, where they have a high strain capability to cope with thermal shrinkage stresses. Additionally, they offer superior fatigue resistance and durability over standard bitumen.
More recently, polymers have found widespread use and acceptance with paving material manufacturers and contractors. Utilizing Polymer Modified Bitumens (PMB) in roadway mixes results in a variety of performance and property improvements. The high temperature grade can be increased, with beneficial effects on stiffness and deformation. More importantly, the rutting resistance and damage tolerance are all significantly improved, which leads to more durable roads able to withstand increased traffic loads.
As a plastomeric polymer, Sripath’s PGXpand® is a unique, highly bitumen-compatible, specially engineered polymer. Used for bitumen modification in both the roofing and paving industries, extensive testing and real-world applications since 2015 have proven its effectiveness and cost-saving benefits.
PGXpand does not confer elastic recovery properties to the bitumen. While elastic recovery and MSCR recovery may be indicative of elastomeric polymer presence in bitumen, many leading experts now question the validity of the alleged relationship between these properties and performance. From a roadway performance standpoint, PGXpand confers outstanding, durable property profiles to the roadway for targeted weather and traffic conditions.
PGXpand modifies the key performance qualities of bitumen, such as, softening point, true high grade, and rutting performance, while reducing or eliminating the need for elastomer content. While boosting the high temperature performance, it has no impact on the low temperature performance of the bitumen. The use of PGXpand in hot spray seal applications is also growing as a solution to mitigating difficulties encountered with the use of crumb rubber.
For all these reasons, choosing a specially engineered polymer modifier like PGXpand is the right choice for both roofing and paving applications.
More information on PGXpand can be found in our detailed technical overview.