Circular construction: making bricks from industrial waste

Firing bricks and making mortar and cement can be costly, but organic chemists at Flinders University are working on more sustainable alternatives — focusing on building materials made from waste products.

In another move into the circular economy, researchers from the Flinders Chalker Lab have used low-cost feedstocks to make lightweight but durable polymer building blocks which can be bonded together with an adhesive-free chemical reaction.

Their latest study tested the strength of these materials and explored ways they can be reinforced in construction.

Matthew Flinders Professor of Chemistry Justin Chalker said the need to develop sustainable building materials is increasingly important, with cement, iron and steel production accounting for more than 15% of global CO₂ emissions each year.

“In this study, we tested a new type of brick we can make from waste cooking oil, mixed with sulfur and dicyclopentadiene (DCPD). Both sulfur and DCPD are by-products of petroleum refining.

“The bricks bond together without mortar upon application of a trace amount of amine catalyst.

“All the starting materials are plentiful and can be classified as industrial waste.

“This research is part of a larger effort to move towards a sustainable built environment,” said project leader Chalker.

The Chalker Lab’s new polymer research team at Flinders University’s College of Science and Engineering is collaborating with Clean Earth Technologies for further development scale-up and possible commercialisation.

Chalker Lab research associate Dr Maximilian Mann said as well as repurposing waste materials into value-added construction materials, the polymer bricks’ sulfur–sulfur bond means they can be bound together without mortar.

By applying an amine catalyst, the bricks bond together and become a single monolith. Image credit: Flinders University

“The bonding in this novel catalytic process is very strong, producing a sustainable construction material with its own mortar which will potentially streamline construction,” Mann said.

First author Paris Pauling said the research is an excellent example of new scientific developments in sustainable materials science.

The latest research tested the new bricks’ mechanical properties and looked at ways to reinforce them in construction, including with carbon fibre fillers. The findings are published in the journal Macromolecular Chemistry and Physics.

Top image credit: iStock.com/Eoneren