What recycled plastic can do: Blocks made from biocomposites for the "Classrooms of Hope" in Indonesia

There is much discussion these days about the circular economy, and the means for incorporating plastics into this model. Recycling a used plastic bottle back into a clean, new bottle has some obvious environmental advantages. But a much more impactful model, in many cases, would involve turning tons of discarded plastics into products with a very long lifespan.

Using recycled plastics in construction or in roadways, for example, helps to take those materials out of circulation for many years. And there can be additional benefits – such as leveraging plastics' light weight, durability and elasticity to enhance the final products.

Two groups in very different parts of the world – Finland's Block Solutions Oy and Costa Rica's Center for Regenerative Design and Collaboration – are doing just this.

Block Solutions is combining mixed recycled polypropylene (PP) and other plastics with wood-fiber byproducts from Finland’s forest industry to produce a biocomposite. It then is injection molding this material to produce large, patent-pending, Lego-like blocks that snap together and can be used to construct low-cost buildings. The firm says it can also use plain recycled plastics to make the blocks.

For its first major project, the company used its beige Eco-Blocks to rebuild a five-classroom school in a small, earthquake-devastated village in Lombok, Indonesia.

In a recent interview with social enterprise news outlet Pro Bono Australia, Duncan Ward, the Indonesia-based founder of Classroom of Hope Ltd., said of Eco-Blocks: "It took six days to build the school with these things. It would usually take around three to six months [to build a school], but these blocks are fully interlocking and come in groups of two, four, and eight, which makes things quicker."

The lightweight blocks have a degree of elasticity, thanks to the plastic in them, which makes them less likely to cause significant harm in earthquake-prone areas. The weight of the Eco-Block wall is only one-tenth that of a conventional cinder-block wall.

An Eco-Block building also costs much less to construct compared with typical methods. "A standard government classroom in Southeast Asia costs on average US$14,000," Ward said. "An Eco-Block classroom costs about $7,000. Plus, it only takes around five hours to build."

The Classroom of Hope team has now ordered enough Eco-Blocks to rebuild eight schools previously destroyed in the earthquake – making the startup of a factory to make the blocks in Indonesia vitally important. Block Solutions hopes to have the plant up and running by mid-2022.

"Once the factory is built, Classroom of Hope will become a major customer and we'll launch a program to build the additional 200 Lombok schools that were lost in the 2018 earthquake," Ward said. Additionally, the South African-born Ward told Pro Bono Australia, "For every classroom we can build with Eco-Blocks, we’re also removing two to three tonnes of plastic waste from the environment."

Block Solutions CEO Sanna Silfverberg explained in an email interview that her firm collects its plastic feedstock from "normal household waste or other sources with safe and traceable origins." The firm's recycling partners "provide us with proof of origin for the material," she said. "This is really to make sure that the blocks are safe to build with."

The resulting biocomposites contain 50 to 70 percent plastic, and the firm currently does not incorporate any additives into the compounds. She said the company can use waste PP, polyethylene (PE) and PET, and continues to investigate other resins.

Outside of Finland, Block Solutions says it expects to use alternate fibers for its product, such as bamboo, sugarcane, acacia and rice husk. "The carbon footprint of our product is close to zero," the company claims.

The Eco-Blocks are joined together using a rubber hammer, and can be modified with normal woodworking machines, for example, to cut out holes for electrical sockets. "A 30-square-meter building can be built in 2.5 hours by two persons without any professional experience in construction," the company says on its website.

"PP is the most suitable resin for processing and gives good quality finishing and strength," Silfverberg noted. "PE is also very close in performance to PP, but a little softer. PET has a slight disadvantage with the weight and processing, but it is working nicely in the production."

Compared to typical, 5-inch cinder blocks, Eco-Blocks offer roughly double the load capacity. Block Solutions notes that an extensive set of tests have been performed by an external accredited institute to verify the product's characteristics. This includes thermal conductivity (U-value determination), fire testing, load-bearing and tensile-strength testing. The blocks do need to be covered with gypsum board or concrete, the company noted, in order to reach the needed fire-resistance requirements.

While Block Solutions currently operates only three injection presses in Finland, the company is preparing to set up numerous factories in the next six to nine months, in Indonesia, Ghana, Rwanda, Uganda, Egypt and Kenya, with additional plants also in the works. The firm says it is making progress in Australia, Brazil, New Zealand, Vietnam and Malaysia.

The company typically uses 650-tonne injection presses, but Silfverberg says they are investigating using 1,200-tonne machines with dual-cavity molds. China-based Haitian is one of the firm’s main suppliers. But In Europe, it also is looking at KraussMaffei and Engel machines.

The first factory outside of Europe will be in Ghana, within a recycling facility that already has more than 10 injection molding machines with clamping forces that exceed 600 tonnes. Production is expected to begin there by the end of this year.