Scientists have managed to create new cement. more sustainable and with greater resistance.
Researchers at Northwestern University, USA, reinforce the material with graphene nanoparticles and find improvements in fracture and infiltration problems
The study, published in Philosophical Transactions of the Royal Society A, says it is a smarter, more durable and highly functional cement.
As cement is the most consumed material globally and the industry that produces it is responsible for 8% of human-caused greenhouse gas emissions, civil and environmental engineering professor Ange-Therese Akono turned to the nano-reinforced version in search of a solution.
Akono, lead author of the study and a researcher at the Faculty of Engineering, says that nanomaterials reduce the carbon footprint of cement, but until now, little was known about their impact on the fracture behavior of infrastructure.
“As an expert in fracture mechanics, I wanted to understand how to change cement production to improve the response to this problem,” she says.
She explains that traditional fracture testing, in which a series of light beams is thrown into a large block of material, involves a lot of time and components and rarely leads to the discovery of new raw materials. Akono then developed a new method, called the scratch test, which assesses the crack response by applying a conical probe with increasing vertical force against the surface of microscopic pieces of cement.
According to the researcher, this requires fewer materials and accelerates discoveries.
“I was able to see many different materials at the same time,” she says.
“My method is directly applied to the micrometer and nanometer scales, which saves a considerable amount of time. So, based on that, we can understand how materials behave, how they crack and ultimately predict their fracture toughness.”
Predictions obtained through scratch testing also allow engineers to make changes to materials that improve their performance.
In the article, graphene nanoplates, a carbon structure that is rapidly gaining popularity in the formation of smart materials, were used to improve the fracture resistance of common cement.
Incorporating a small amount of nanomaterial also improved water transport properties, including pore structure and resistance to liquid penetration, with reported relative decreases of 76% and 78%, respectively.
Akono says the study's implications span many fields, including building construction, road maintenance, optimizing sensors and generators, and monitoring structural integrity.
She points out that smart materials allow cities to meet the needs of growing populations in terms of connectivity, energy and multifunctionality.
The engineer says she is excited by the prospect that her research could influence other teams. She says that she is already working on proposals aimed at using construction waste to form new concrete and is considering going even further, increasing the fraction of nanomaterial that cement contains. “I want to look at other properties, like understanding long-term performance. For example, if you have a building made of carbon-based nanomaterials, how can you predict the strength in 10, 20 or 40 years?”