A team of Chinese researchers has created a low-carbon building material from brick waste, sand and other mineral grains. The inspiration for their breakthrough came from an unlikely source: sandcastle worms.
Also referred to as honeycomb tube worms, the diminutive marine species build reefs by secreting sand particles combined with a glue-like substance, creating small ecosystems and cover for sandworm colonies and other small sea creatures.
Now, scientists from the Beijing-based Chinese Academy of Sciences (CAS) Technical Institute of Physics and Chemistry, say they have developed an environmentally friendly alternative to traditional building materials using a similar technique.
Their work, published in the September issue of Matter, details the “urgent” need to find substitutes for resources, including steel, aluminium, brick and concrete, all of which have a significant carbon footprint.
The production and manufacturing of construction materials accounted for an estimated 9 per cent of the Earth’s total energy-related greenhouse emissions for 2021, according to a recent report by the Global Alliance for Building and Construction.
The research team noted that while natural materials, such as cork, strawbale and sandbags, are kinder to the planet, they are less resilient and have “weaker mechanical properties”.
Keen to find a more suitable alternative, the researchers, led by CAS scientist, Professor Wang Shutao, looked to sandcastle worms that secrete a protein-based bio-adhesive combined with sand and shell fragments to build the protective, tube-shaped structures they inhabit.
The roughly 7.5-centimetre-long marine worm is predominately found off the coast of southern California and Baja, Mexico, where it lives in massive colonies.
Wang and his peers discovered the glue-like substance created by the worms consists of both positively and negatively charged polyphenolic proteins. While the specific biological mechanism for the process remains unclear, the researchers noted a “strong charge attraction” between the oppositely charged proteins.
The CAS team attempted to recreate this by using bio-polymers as a binding agent for building materials. Unlike cement and steel, its production does not use any heat or pressure, requiring less energy in the process.
In their findings, the team noted the materials created with the novel substance were resilient enough to reach and surpass the minimum standards building materials are required to meet to be considered safe.
Wang and his partners also found that it maintained its integrity even after prolonged exposure to the elements. In addition, the bio-adhesive is versatile and can be combined to effectively produce building materials from desert sand, sea sand, rubble, coal particles and concrete slag.
Notably, the material possesses a “unique recyclability” and can be used and re-used several times over, while maintaining its strength and elasticity.
As the developing world seeks to build infrastructure, the demand for raw materials has skyrocketed, with demand for concrete, steel and brick expected to double by 2060.
Wang and his colleagues are hopeful their more environmentally friendly, worm-inspired option can provide a more natural alternative for developers in the future.