Study investigates capillary-induced deformations in cement’s porous structure.

Although it is used to construct some of the world’s largest structures, it turns out that cement actually has something in common with a sponge.A highly porous material, cement tends to absorb water from precipitation and even ambient humidity. And just as the shape of a sponge changes depending on water saturation, so too does that of cement, according to recent work conducted at MIT. In a paper published in the Proceedings of the National Academy of Sciences, researchers at the MIT Concrete Sustainability Hub (CSHub), French National Center for Scientific Research (CNRS) and Aix-Marseille University discuss just how the material’s porous network absorbs water and propose how drying permanently rearranges the material a...

The way streets and buildings are arranged makes a big difference in how heat builds up, study shows.

When you deform a soft material such as Silly Putty, its properties change depending on how fast you stretch and squeeze it. If you leave the putty in a small glass, it will eventually spread out like a liquid. If you pull it slowly, it will thin and droop like viscous taffy. And if you quickly yank on it, the Silly Putty will snap like a brittle, solid bar.

Scientists use various instruments to stretch, squeeze, and twist soft materials to precisely characterize their strength and elasticity. But typically, such experiments are carried out sequentially, which can be time-consuming.

Now, inspired by the sound sequences used by bats and dolphins in echolocation, MIT engineers have dev...

The aim of Cement and Concrete Research is to publish the best research on cement, cement composites, concrete and other allied materials that incorporate cement.

In doing so, the journal will present: the results of research on the properties and performance of cement and concrete; novel experimental techniques; the latest analytical and modelling methods; the examination and the diagnosis of real cement and concrete structures; and the potential for improved materials. The fields which the journal aims to cover are:

• Processing: Cement manufacture, mixing and rheology, admixtures and hydration. While the majority of articles will be concerned with Portland cements, we encourage articles on other cement systems, such as calcium aluminate.
• Structural and Microstructural Cha...

April 13th, 2018, M.I.T. McGovern Institute, Cambridge, MA.

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Bringing together experts from physiology, sports medicine, engineering and physics to explore current and future directions in this newly emerging interdisciplinary field. The workshop is open to scientists from academia and industry, and interested runners. All participants must register on this website before April 6, 2018. The scope of this interdisciplinary workshop is to bring together experts from physiology, sports medicine, engineering and physics. With the rapid development of wearable technologies that can monitor a plethora of biomechanical and physiological data during exercise, an en...

The way streets and buildings are arranged makes a big difference in how heat builds up, study shows.

The arrangement of a city’s streets and buildings plays a crucial role in the local urban heat island effect, which causes cities to be hotter than their surroundings, researchers have found. The new finding could provide city planners and officials with new ways to influence those effects. Some cities, such as New York and Chicago, are laid out on a precise grid, like the atoms in a crystal, while others such as Boston or London are arranged more chaotically, like the disordered atoms in a liquid or glass. The researchers found that the “crystalline” cities had a far greater buildup of heat compared to their surroundings than did the “glass-like” ones. The study, published today in the journal Phy...

MultiScale Material Science for Energy and Environment research partnership could reduce the carbon footprint of materials such as concrete.

MIT President L. Rafael Reif joined a high-level delegation of French officials at MIT on Friday to sign an agreement extending the research partnership behind MultiScale Material Science for Energy and Environment (MSE2), an international joint unit, or UMI (reflecting the French term "unité mixte internationale"), that has produced groundbreaking research into such complex materials as concrete and shale rocks. Reif signed the agreement with Alain Fuchs, president of the French National Center for Scientific Research (CNRS), and Yvon Berland, president of Aix-Marseille University, extending the...

New understanding of concrete’s properties could increase lifetime of the building material, decrease emissions.

An MIT-led team has defined the nanoscale forces that control how particles pack together during the formation of cement “paste,” the material that holds together concrete and causes that ubiquitous construction material to be a major source of greenhouse gas emissions. By controlling those forces, the researchers will now be able to modify the microstructure of the hardened cement paste, reducing pores and other sources of weakness to make concrete stronger, stiffer, more fracture-resistant, and longer-lasting. Results from the researchers’ simulations explain experimental measurements that have confused observers for decades, and they may guide the way to other improvements, such as adding polym...

About half of humanity lives in urban environments today and that number will grow to 80% by the middle of this century; North America is already 80% in cities, rising to 90% by 2050. Cities have to be efficient, resilient, and sustainable, and they must address quality of life issues for their citizens. To achieve these goals, one has to understand the various processes  and phenomena that determine the functioning of cities. Examples to be addressed in this workshop include climate, traffic, energy and resource conservation. We expect that concepts from statistical physics can take us beyond today’s imperfect and often anecdotal view of cities. Today, new technologies provide opportunities for sensors to acquire a plethora of data with high spatial and temporal resolution, including light, temperature, wind...

Findings may guide development of formulas to make the material more durable, less CO2-intensive.

Concrete is the world’s most widely used construction material, so abundant that its production is one of the leading sources of greenhouse gas emissions. Yet answers to some fundamental questions about the microscopic structure and behavior of this ubiquitous material have remained elusive.  

Concrete forms through the solidification of a mixture of water, gravel, sand, and cement powder. Is the resulting glue material — known as cement hydrate, or calcium silicate hydrate (CSH) — a continuous solid, like metal or stone, or is it an aggregate of small particles?

As basic as that question is, it had never been definitively answered. In a paper published this week in the Proceedings of t...

Nanopores may be trapping oil and gas in the ancient hydrocarbon instead of allowing them to flow.

The dark-colored hydrocarbon solid known as kerogen gives rise to the fuels that power many of our daily activities: Petroleum is the source of gasoline and diesel fuels, and natural gas is used for cooking, heating, and increasingly for producing electricity. And yet, kerogen’s basic internal structure has remained poorly understood — until now. A new analysis, by a joint team of researchers at MIT, the French government research organization CNRS, and elsewhere, has revealed kerogen’s internal structure, in detail down to the atomic level. Their results were just published in the journal Nature Materials in a paper by MIT postdoc Colin Bousige, visiting scientist Benoit Coasne, senior research scientist Roland J.-M...

New research shows concrete is a strong choice for the long-term confinement of nuclear waste.

One of the main challenges faced by the nuclear industry is the long-term confinement of nuclear waste. Concrete is one of the barrier materials commonly used to contain radionuclides, both in nuclear reactors and nuclear waste-storing facilities. For this reason, it is extremely important that researchers and industry professionals understand the chemical and structural stability of cement (the basic binding ingredient in concrete) containing radioactive materials.

A new study by researchers from the...

Franz-Josef Ulm explores the physics of dirty materials and messy systems to advance sustainable infrastructure and clean energy technology.

Franz-Josef Ulm works on big issues such as concrete manufacturing, urban architecture, and gas shale recovery. All involve “the physics of what many consider dirty materials and messy systems,” he says. His intent is to make each of these more efficient, durable, and environmentally sound. While the vision is grand, the approach is anything but. The civil and environmental engineering professor and co-director of the MIT MultiScale Material Science for Energy and Environment international joint unit (MIT-CNRS-UMI), a venture between the Institute and France’s National Center for Scientific Research, wo...

Analysis of material's molecular structure leads to a new formula that could cut greenhouse-gas emissions.

Concrete is the world’s most-used construction material, and a leading contributor to global warming, producing as much as one-tenth of industry-generated greenhouse-gas emissions. Now a new study suggests a way in which those emissions could be reduced by more than half — and the result would be a stronger, more durable material.

The findings come from the most detailed molecular analysis yet of the complex structure of concrete, which is a mixture of sand, gravel, water, and cement. Cement is made by cooking calcium-rich material, usually limestone, with silica-rich material — typically clay — at temperatures of 1,500 degrees Celsius, yielding a hard mass called “clinker.” This...

Franz-Josef Ulm's serendipitous observation leads to research linking physics and urban planning.

Franz-Josef Ulm and a colleague were taking a break from a tough problem one afternoon when they spotted an aerial photograph of a city and had an epiphany. Instantly, they made a connection between the patterns of houses and streets and the underlying molecular structure of cement.

That serendipitous observation has since led to research that is tying together the seemingly disparate disciplines of physics and urban planning. "Ultimately, I believe there's potential for this to become a new field of study," says Ulm, the George Macomber Professor in the Department of Civil and Environmental Engineering, and co-director with Senior Research Scientist Roland Pellenq of the International Joint Uni...