Bitumen quality and Covid-19.

Bitumen quality and Covid-19.

What is bitumen? - it is a byproduct of crude oil fractional distillation from the refining process with its parent feedstock crude oil and refining technology determining its quality. What then is bitumen quality? - this is the unique chemical fingerprint that is based on crude oil source which varies from well to well. Chemically, bitumen consists of different fractions of saturates, aromatics, resins and asphaltenes (SARA) which determine its behaviour when applied as a bituminous binder for roads. It does not end there, the modification of bitumen using polymers, crumb rubber, elastomers and other different types of additives depends on the SARA fractions. Hence, bitumen quality for reproducibility of results depends on its parent source and with the Covid-19 pandemic the impact on supply chain will definitely play a major role in the changes experienced when it comes to different applications of bitumen. This article will focus on the following aspects:

• What are the applications of bitumen?
• How does supply affect bitumen quality?
• What are the recommendations for avoiding shock results when it comes to applications?

What are the applications of bitumen?

There are different applications of bitumen and these include:

• binder for stone aggregate in asphalt for roads.
• phase component of bitumen emulsions used for roads and dust suppression.
• main component of bitumen rubber used for roads.
• main component of polymer modified bitumen used for roads.
• as a sealant in roofing applications.
• inner linings for doors in the motor vehicle industry

How does supply affect bitumen quality?

The bitumen fingerprint depends on its crude oil source. Different sources of crude oil also imply different bitumen fingerprints. The connection between source and application is cemented by understanding how source affects quality. The bitumen quality governs performance when it is mixed with different additives such as polymers, crumb rubber, elastomers, plastomers just to mention but a few. The moment the source of crude oil changes the bitumen chemistry also changes. So how is Covid-19 related to bitumen quality? A hold up in supply as a result of the pandemic can result in changing of sources of crude oil sources for refineries. Especially at peak times when the demand for bitumen is high but the usual suppliers are not able to meet the timelines as a result of Covid-19 disruptions. The variation in crude prices as well could fluctuate and it would make business sense to go for a cheaper crude given the losses incurred as a result of Covid-19. All these changes can definitely impact bitumen quality when used for different applications.

The moment a supplier changes your SARA fractions change which has a bearing on performance on the different applications. Stringent specifications regulate the use of bitumen products in different fields. For example in the inner linings for doors in the motor vehicle industry the emissions are critical to application of bitumen and a change in SARA fractions has a bearing on your volatiles in the emission standard testing hence supply of crude affects bitumen quality. In the road construction industry, the swelling behavior of polymers depends on the SARA fractions and again a change in supply of crude oil has a bearing on bitumen quality and overall performance when used as a binder.

What are the recommendations for avoiding shock results when it comes to applications?

• Understanding your SARA fractions is non-negotiable to build predictable performance based on the bitumen fingerprint which is unique to the parent crude source.
• A change in supplier of crude should be communicated downstream to the different applications of bitumen so that they can be prepared to deal with the changes from a formulation point of view.
• I can't emphasize enough the importance of binder-additive chemistry in the performance of bituminous binders. Chemistry governs performance of bitumen and more so when other additives are added to improve its qualities.

Bitumen quality and Covid-19 have highlighted a critical and yet often underestimated aspect of inconsistencies in material performance as a result of bitumen fingerprint. Binder fingerprinting is key before any application to formulate the different product streams with background understanding of the SARA fractions and how they are bound to affect the expected performance in service and over the life-cycle of the different applications.

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