Green’ fly ash could be a viable alternative in development

research from the University of Alberta has put a B.C.-based company one step closer to ‎developing a green alternative to fly ash used in cement.‎

Progressive Planet, a mineral exploration company with its flagship Z1 zeolite Quarry in B.C., ‎announced its project with the university to modify the rheology of its zeolite mixture has been ‎successful. Rheology, or slump, refers to the flow of something, a key aspect of properly pouring ‎cement.‎

Researchers found the mixture, which includes zeolite, recycled glass that has been pulverized and ‎other proprietary ingredients, has been able to achieve a slump better than targeted. Now the team is ‎working to get CSA testing conducted so the product can be ready for commercial use as a ‎supplementary cementing material.‎

Steve Harpur, CEO of Progressive Planet, said he not only sees an opportunity to fill in a gap as the ‎coal plants that supply fly ash are phased out, but also put a dent in one of the globe’s worst ‎sources of pollution.‎

Large amounts of glass end up in landfills that could easily be used in a cement mix. And the ‎cement making process is less polluting as well.‎

Harpur explained that traditional fly ash must be heated to over 1,000 degrees several times, ‎requiring a large amount of energy and releasing almost half of the fly ash material as carbon ‎dioxide.‎

‎“This is the main reason that the production of Portland cement is the second biggest man-made ‎cause of CO2 pollution,” said Harpur. “It’s absolutely monstrous. It’s a tremendously destructive ‎force in global warming.” ‎

Harpur explained natural pozzolans like zeolite are volcanic in origin and have already been rapidly ‎heated and cooled. This makes them amorphous in structure rather than crystalline. They only need ‎to be ground into a fine powder to be used in a cement mixture rather than heated.‎

The material’s use in construction is ancient. Harpur explained pozzolanic ash was famously used ‎in the roman concrete that makes up the Parthenon’s dome. The structure remains the world’s ‎largest and oldest unreinforced concrete dome.‎

Harpur said he anticipates being able to soon sell a product that could be used to reduce the amount ‎of Portland cement in a mix by 20 per cent.‎

But first the product must go through several CSA tests that measure compressive strength, alkali-‎silica reaction, sulphate resistance and freeze-thaw resistance. In addition, one American Society ‎for Testing and Materials test will be completed to analyze air voids.‎

The company will be targeting the 2021 construction season to have a commercial product that it ‎can offer as a competitive alternative to fly ash to the ready mix and pre-cast concrete industries in ‎B.C. and Alberta.‎

Harpur explained traditional fly ash is already becoming scarce. Coal plants that produce electricity ‎and fly ash are already starting to get phased out and by 2029 they won’t be allowed in some ‎provinces.‎

Harpur hopes the technology can go even further than just a supplementary material. Progressive ‎Planet is already in the early stages of researching a geopolymer mix without any Portland cement ‎and even developing a way to reverse the cement making process to sequester carbon.‎

‎“Concrete is the most consumed building material in the world,” said Harpur. “We don’t have a ‎perfect solution but it’s a better solution. Our corporate values are to continue to find better ‎solutions. That’s why we were so excited to be taking a product, glass, that is basically single use ‎and it can be involved in structures for decades.”‎