Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Rice U probes ways to turn cement's weakness to strength: Rice University lab's calculations show new mechanisms to induce strength, ductility into concrete

A screw dislocation disrupts the regular rows of atoms in tobermorite, a naturally occurring crystalline analog to the calcium-silicate-hydrate that makes up cement. Rice University scientists simulated tobermorite to see how it uses dislocations to relieve stress when used in concrete.
CREDIT
Multiscale Materials Laboratory/Rice University
A screw dislocation disrupts the regular rows of atoms in tobermorite, a naturally occurring crystalline analog to the calcium-silicate-hydrate that makes up cement. Rice University scientists simulated tobermorite to see how it uses dislocations to relieve stress when used in concrete. CREDIT Multiscale Materials Laboratory/Rice University

Abstract:
Concrete isn't thought of as a plastic, but plasticity at small scales boosts concrete's utility as the world's most-used material by letting it constantly adjust to stress, decades and sometimes even centuries after hardening. Rice University researchers are a step closer to understanding why.

Rice U probes ways to turn cement's weakness to strength: Rice University lab's calculations show new mechanisms to induce strength, ductility into concrete

Houston, TX | Posted on January 6th, 2017

The Rice lab of materials scientist Rouzbeh Shahsavari performed an atom-level computer analysis of tobermorite, a naturally occurring crystalline analog to the calcium-silicate-hydrate (C-S-H) that makes up cement, which in turn holds concrete together. By understanding the internal structure of tobermorite, they hope to make concrete stronger, tougher and better able to deform without cracking under stress.

Their results appear this week in the American Chemical Society journal ACS Applied Materials and Interfaces.

Tobermorite, a key element in the superior concrete Romans used in ancient times, forms in layers, like paper stacks that solidify into particles. These particles often have screw dislocations, shear defects that help relieve stress by allowing the layers to slide past each other. Alternately, they can allow the layers to slip only a little before the jagged defects lock them into place.

The researchers built the first computer models of tobermorite "super cells" with dislocations either perpendicular to or in parallel with layers in the material, and then applied shear force. They found that defect-free tobermorite deformed easily as water molecules caught between layers helped them glide past each other.

But in particles with screw defects, the layers only glided so far before being locked into place by the tooth-like core dislocations. That effectively passed the buck to the next layer, which glided until caught, and so on, relieving the stress without cracking.

This "step-wise defect-induced gliding" around the particle's core makes it more ductile and able to adjust to stress, Shahsavari said, an assistant professor of civil and environmental engineering and materials science and nanoengineering.

"The insight we get from this study is that unlike the common intuition that defects are detrimental for materials, when it comes to complex layered crystalline systems such as tobermorite, this is not the case," said Shahsavari, "Rather, the defects can lead to dislocation jogs in certain orientations, which acts as a bottleneck for gliding, thus increasing the yield stress and toughness.

"These latter properties are key to design concrete materials, which are concurrently strong and tough, two engineering features that are highly desired in several applications. Our study provides the first report on how to leverage seemingly weak attributes -- the defects -- in cement and turn them to highly desired properties, high strength and toughness."

Shahsavari said he hopes the work will provide design guidelines for developing stronger, tougher concrete and other complex materials.

###

Rice postdoctoral researcher Ning Zhang is lead author of the paper and Philippe Carrez, a professor at the Lille University of Science and Technology, Villeneuve d'Ascq, France, is a co-author.

The National Science Foundation (NSF) supported the research. Computing resources were supplied by the National Institutes of Health and an IBM Shared University Research award in partnership with CISCO, Qlogic and Adaptive Computing, as well as Rice's NSF-supported DAVinCI supercomputer administered by Rice's Center for Research Computing and were procured in partnership with Rice's Ken Kennedy Institute for Information Technology.

####

About Rice University
Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,910 undergraduates and 2,809 graduate students, Rice's undergraduate student-to-faculty ratio is 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for happiest students and for lots of race/class interaction by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to http://tinyurl.com/RiceUniversityoverview .

Follow Rice News and Media Relations via Twitter @RiceUNews

For more information, please click here

Contacts:
David Ruth

713-348-6327

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

Read the abstract at:

Multiscale Materials Laboratory home page:

George R. Brown School of Engineering: http://engineering.rice.edu

Rice Department of Civil and Environmental Engineering:

Rice Department of Materials Science and NanoEngineering:

Related News Press

News and information

Cryo-electron microscopy achieves unprecedented resolution using new computational methods March 25th, 2017

Argon is not the 'dope' for metallic hydrogen March 24th, 2017

Promising results obtained with a new electrocatalyst that reduces the need for platinum: Researchers from Aalto University have succeeded in manufacturing electrocatalysts used for storing electric energy with one-hundredth of the amount of platinum that is usually needed March 24th, 2017

Artificial photosynthesis steps into the light: Rice University lab turns transition metals into practical catalyst for solar, other applications March 23rd, 2017

Govt.-Legislation/Regulation/Funding/Policy

Cryo-electron microscopy achieves unprecedented resolution using new computational methods March 25th, 2017

Argon is not the 'dope' for metallic hydrogen March 24th, 2017

Nanobiotix: The Independent Data Monitoring Committee Recommends the Continuation of the Ongoing Phase II/III Trial of NBTXR3 in Soft Tissue Sarcoma March 23rd, 2017

Rice U. refines filters for greener natural gas: New study defines best materials for carbon capture, methane selectivity March 23rd, 2017

Possible Futures

Cryo-electron microscopy achieves unprecedented resolution using new computational methods March 25th, 2017

Argon is not the 'dope' for metallic hydrogen March 24th, 2017

Promising results obtained with a new electrocatalyst that reduces the need for platinum: Researchers from Aalto University have succeeded in manufacturing electrocatalysts used for storing electric energy with one-hundredth of the amount of platinum that is usually needed March 24th, 2017

Rice U. refines filters for greener natural gas: New study defines best materials for carbon capture, methane selectivity March 23rd, 2017

Discoveries

Cryo-electron microscopy achieves unprecedented resolution using new computational methods March 25th, 2017

Argon is not the 'dope' for metallic hydrogen March 24th, 2017

Promising results obtained with a new electrocatalyst that reduces the need for platinum: Researchers from Aalto University have succeeded in manufacturing electrocatalysts used for storing electric energy with one-hundredth of the amount of platinum that is usually needed March 24th, 2017

Artificial photosynthesis steps into the light: Rice University lab turns transition metals into practical catalyst for solar, other applications March 23rd, 2017

Materials/Metamaterials

Argon is not the 'dope' for metallic hydrogen March 24th, 2017

Promising results obtained with a new electrocatalyst that reduces the need for platinum: Researchers from Aalto University have succeeded in manufacturing electrocatalysts used for storing electric energy with one-hundredth of the amount of platinum that is usually needed March 24th, 2017

Rice U. refines filters for greener natural gas: New study defines best materials for carbon capture, methane selectivity March 23rd, 2017

Artificial photosynthesis steps into the light: Rice University lab turns transition metals into practical catalyst for solar, other applications March 23rd, 2017

Announcements

Cryo-electron microscopy achieves unprecedented resolution using new computational methods March 25th, 2017

Argon is not the 'dope' for metallic hydrogen March 24th, 2017

Promising results obtained with a new electrocatalyst that reduces the need for platinum: Researchers from Aalto University have succeeded in manufacturing electrocatalysts used for storing electric energy with one-hundredth of the amount of platinum that is usually needed March 24th, 2017

Artificial photosynthesis steps into the light: Rice University lab turns transition metals into practical catalyst for solar, other applications March 23rd, 2017

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

Argon is not the 'dope' for metallic hydrogen March 24th, 2017

Promising results obtained with a new electrocatalyst that reduces the need for platinum: Researchers from Aalto University have succeeded in manufacturing electrocatalysts used for storing electric energy with one-hundredth of the amount of platinum that is usually needed March 24th, 2017

Rice U. refines filters for greener natural gas: New study defines best materials for carbon capture, methane selectivity March 23rd, 2017

Artificial photosynthesis steps into the light: Rice University lab turns transition metals into practical catalyst for solar, other applications March 23rd, 2017

Construction

Next-gen steel under the microscope March 18th, 2017

Graphene foam gets big and tough: Rice University's nanotube-reinforced material can be shaped, is highly conductive February 13th, 2017

New low-cost technique converts bulk alloys to oxide nanowires January 24th, 2017

Diamond nanothread: Versatile new material could prove priceless for manufacturing: Would you dress in diamond nanothreads? It's not as far-fetched as you might think November 3rd, 2016

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project