Asphalt Made with Olive Oil Byproducts Used to Pave a Highway in Spain

Local officials said the experimental asphalt is more environmentally friendly to manufacture, safer for workers and could provide new revenue for producers.
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By Daniel Dawson
Aug. 10, 2023 15:15 UTC

Officials in north­ern Spain are test­ing a new type of asphalt man­u­fac­tured using tra­di­tional petro­chem­i­cals mixed with mate­ri­als derived from the olive oil refin­ing process, accord­ing to local media reports.

Authorities in Castile and León will pave a 40-meter sec­tion of heav­ily tran­sited high­way con­nect­ing the autonomous community’s two largest cities – Valladolid and Segovia – with the exper­i­men­tal asphalt. Another 40-meter sec­tion of the high­way will be paved with con­ven­tional asphalt.

The exper­i­men­tal asphalt is made with a mix­ture of semi-hot bitu­men, a byprod­uct of the petro­leum refin­ing process, byprod­ucts from the olive oil refin­ing process and recy­cled veg­etable oil.

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For every 1,000 liters of semi-hot bitu­men, the new man­u­fac­tur­ing process requires 300 liters of olive oil refin­ing byprod­uct and 400 liters of recy­cled veg­etable oil.

The offi­cials plan to com­pare the per­for­mance of the two sec­tions over time. They hope the exper­i­men­tal asphalt, which is less energy-inten­sive to pro­duce and emits fewer toxic fumes dur­ing its appli­ca­tion, will prove to be as durable as the tra­di­tional for­mu­la­tion or even bet­ter.

Previous research has indi­cated that asphalt made with byprod­ucts from olive oil pro­duc­tion may be more resilient than tra­di­tional asphalt.

A 2021 study con­ducted by the Olive Oil Commission of California found that adding olive pomace to asphalt binder enhanced the resilience of the paving mate­r­ial to crack­ing and other forms of weath­er­ing.

According to local author­i­ties in Castile and León, the exper­i­men­tal asphalt can be pro­duced at tem­per­a­tures 40 degrees (Celcius) cooler than tra­di­tional asphalts, which would greatly reduce the amount of energy required to man­u­fac­ture them and result in fewer green­house gas emis­sions.

Furthermore, the offi­cials sug­gested that the exper­i­men­tal asphalt for­mu­la­tion would improve work­ing con­di­tions since it emits less smoke and odor while being poured than nor­mal asphalt. Workers are also less likely to be burned since it pours at a lower tem­per­a­ture.

For olive oil pro­duc­ers, more wide­spread adop­tion of the exper­i­men­tal asphalt would cre­ate another stream of rev­enue and help off­set ris­ing pro­duc­tion costs.

Since 2020, researchers in Spain have been look­ing for ways to cre­ate value from the waste cre­ated dur­ing olive oil pro­duc­tion

According to Ainia, a non-profit focused on agribusi­ness, 80 per­cent of the bio­mass of olives trans­formed into oil is con­verted into waste prod­ucts. Removal and treat­ment of these prod­ucts are a sig­nif­i­cant cost for mills but could also pro­vide a com­ple­men­tary stream of rev­enue.


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