Civil and environmental engineering

Bloomberg reporter Akshat Rathi spotlights Sublime Systems, an MIT startup developing new technology to produce low-carbon cement. “Sublime’s solution involves splitting the cement-making process into two steps,” explains Rathi. “The first step is to make calcium—the key element in limestone—in a form that’s ready to chemically react with silicon—the key element in sand. Sublime reduces energy use and carbon emissions in this step by avoiding limestone and using electricity, rather than coal-fired heat.”

Prof. Admir Masic speaks with NPR host Scott Simon about the concrete blend used by the ancient Romans to build long standing infrastructures. “We found that there are key ingredients in ancient Roman concrete that lead to a really outstanding functionality property in the ancient mortar, which is self-healing,” explains Masic.

Reuters reporter Will Dunham writes that a new study by MIT researchers uncovers the secret ingredient that made ancient Roman concrete so durable and could “pave the way for the modern use of a replicated version of this ancient marvel.” Prof. Admir Masic explains that the findings are “an important next step in improving the sustainability of modern concretes through a Roman-inspired strategy.”

MIT researchers have discovered that ancient Romans used lime clasts when manufacturing concrete, giving the material self-healing properties, reports Katie Hunt for CNN. "Concrete allowed the Romans to have an architectural revolution," explains Prof. Admir Masic. "Romans were able to create and turn the cities into something that is extraordinary and beautiful to live in. And that revolution basically changed completely the way humans live."

Scientists from MIT and other institutions have uncovered an ingredient called quicklime used in ancient Roman techniques for manufacturing concrete that may have given the material self-healing properties, reports Jacklin Kwan for Science Magazine. When the researchers made their own Roman concrete and tested to see how it handled cracks, “the lime lumps dissolved and recrystallized, effectively filling in the cracks and keeping the concrete strong,” Kwan explains.

Fast Company reporter Adele Peters writes that researchers from MIT and other institutions have found that a technique employed by ancient Romans for manufacturing concrete contains self-healing properties and could be used to help reduce concrete’s global carbon footprint. The ancient concrete method could open the “opportunity to build infrastructure that is self-healing infrastructure,” explains Prof. Admir Masic.

Researchers at MIT and elsewhere have found that using ancient Roman techniques for creating concrete could be used to create buildings with longer lifespans, reports Nicola Davis for The Guardian. “Roman-inspired approaches, based for example on hot mixing, might be a cost-effective way to make our infrastructure last longer through the self-healing mechanisms we illustrate in this study,” says Prof. Admir Masic.

Researchers at MIT have found that applying ancient Roman techniques for developing concrete could be used to reduce concrete manufacturing emissions, reports Saul Elbein for The Hill. “Researchers said blocks treated with the method — in which concrete was mixed with reactive quicklime under continuous heat — knit themselves back together within a few weeks after being fractured,” writes Elbein.

Researchers at MIT have found indoor humidity levels can influence the transmission of Covid-19, reports Dennis Thompson for US News & World Report. “We found that even when considering countries with very strong versus very weak Covid-19 mitigation policies, or wildly different outdoor conditions, indoor — rather than outdoor — relative humidity maintains an underlying strong and robust link with Covid-19 outcomes,” explains Prof. Lydia Bourouiba.

MIT researchers have found that relative humidity “may be an important metric in influencing the transmission of Covid-19,” reports Sophie Mellor for Fortune, “Maintaining an indoor relative humidity between 40% and 60% – a Goldilocks climate, not too humid, not too dry – is associated with relatively lower rates of Covid-19 infections and deaths,” writes Mellor.

Wired reporter Matt Simon spotlights a study by researchers from MIT and other institutions that finds smartphones in cars could be used to track the structural integrity of bridges. The findings “could pave the way (sorry) for a future in which thousands of phones going back and forth across a bridge could collectively measure the span’s health, alerting inspectors to problems before they’re visible to the human eye,” writes Simon.

Researchers from MIT and elsewhere have found that brown carbon – released from burning biomass – could have a larger impact on the Earth’s climate than originally thought, write University of British Columbia student Nealan Gerrebos and University of British Columbia Prof. Alan Bertram for The Conversation. “The results show a warming effect on the climate from brown carbon that is twice that of the previous estimate,” write Gerrebos and Bertram.

A stamp-sized reusable ultrasound sticker developed by researchers in Prof. Xuanhe Zhao’s research group has been named one of the best inventions of 2022 by TIME. “Unlike stretchy existing ultrasound wearables, which sometimes produce distorted images, the new device’s stiff transducer array can record high-resolution video of deep internal organs (e.g. heart, lungs) over a two-day period,” writes Alison Van Houten.

Researchers from MIT’s Concrete Sustainability Hub discuss their research showing that increasing the reflectivity of paved surfaces could help lower air temperatures in U.S. cities by an average of 2.5 degrees. “If we reflect more energy back out, it’s the same as emitting less CO2,” says Randolph Kirchain, co-director of the Concrete Sustainability Hub.

Researchers at MIT have developed a silk-based biodegradable substitute for microplastics, reports Ysabelle Kempe for Scientific American. “This type of research is urgent for companies that face tightening regulations on deliberate use of microplastics,” writes Kempe.