Stabilizing collapsed or shock-damaged buildings

December 04, 2012

In the gathering gloom of late afternoon, September 11, 2001, building engineers--as well as the rest of the world--watched in horror as the desperately fragile remains of the World Trade Center shifted and settled into their final positions. All immediately knew the risks that would be taken by those brave individuals who would plunge into what was left of those shaky remains in the search for survivors.

The same was true after the Haiti earthquake in 2010, and after the tsunami in Japan, 2011. Buildings collapse the world over due to shoddy construction, storms, tornadoes, earthquakes and tsunamis, as well as acts of terrorism. Stabilizing the remains of any shock-damaged or collapsed building or structure is of the utmost importance in the hours immediately following the event.

Research scientists and engineers at the University of Kentucky Center for Applied Energy Research (CAER) proposed a solution: a product that could be applied quickly and which would set rapidly to allow rescue operations to proceed safely. The National Institute for Hometown Security (NIHS), based in Somerset, KY, teamed up with Homeland Security's Science and Technology Directorate (DHS S&T) to fund the CAER project.

Working with Minova North America Inc. of Georgetown, Kentucky--makers of many steel, chemical and cement products for the mining, tunneling, and civil engineering market--the CAER researchers developed Tekcrete Fast and Tekcrete Fast M (the 'M' is for mining). These products are very rapidly setting, high strength spray-on cement products that are "unlike anything else out there," says Dr. Sam Varnado, chief technical officer at NIHS.

"Anything you spray on a collapsed building is going to add weight to a structure that is already very fragile, and that might further weaken it," says NIHS CEO Ewell Balltrip. "Whatever you come up with must act very, very rapidly to quickly stabilize that structure."

"It was a very tough assignment," adds Lawrence Skelly, S&T Program Manager on the project. "We had to come up with a product that would go over anything, in any condition. In these kinds of situations, there's no time to clean up a collapsed structure, which may not only be hot due to fires, but may have lots of dust and debris that has settled onto it as well."

Minova's "Tekcrete Fast and Tekcrete Fast M" are simple, single bag concretes designed for shotcrete applications. When mixed with water, it not only sets exceedingly quickly, but develops an incredible strength in just a few minutes. "We're talking structural strength in as little as 15 minutes -- unheard of in the cement world," says Skelly. In 15 minutes it develops the same strength that regular cement would take two weeks to develop.

Tekcrete Fast is fiber-reinforced which keeps the concrete intact if cracks try to form when it adheres after applying. Tekcrete Fast M, specifically formulated for the mining industry, is almost dust free. Both form a crystal cement, rather than a gel, which aids in the speed of its hardening. Another key feature of the product is just how "sticky" it is--unusually so for cement-based products. It readily forms strong bonds with almost any kind of concrete, wood or steel. The formula is now patented by the University of Kentucky.

Tekcrete Fast M is currently being tested in underground mines to shore up roofing. The product resulting from the research funded by DHS S&T is now on the market. Aside from the great boon to first responders dealing with shock-damaged buildings, Tekcrete Fast also has many commercial uses in mining, tunneling and bridge construction, and other civil engineering projects.

This summer, Tekcrete Fast was demonstrated to Congressman Hal Rogers (R-KY). A concrete beam was placed horizontally across the top of a vertical concrete column. Tekcrete Fast was applied to the joint with a hose, and 15 minutes later, Congressman Rogers hung from the end of the crossbeam.

"It works," declared Rogers.
-end-


The Nat Institute for Hometown Security

Related Cement Articles from Brightsurf:

The cement for coral reefs
Coral reefs are hotspots of biodiversity. As they can withstand heavy storms, they offer many species a safe home.

Building cities with wood would store half of cement industry's current carbon emissions
A new study has found that shifting to wood as a building construction material would significantly reduce the environmental impact of building construction.

Concrete structure's lifespan extended by a carbon textile
The Korea Institute of Civil Engineering and Building Technology (KICT) has announced the development of an effective structural strengthening method using a noncombustible carbon textile grid and cement mortar, which can double the load-bearing capacities of structurally deficient concrete structures and increase their usable lifespan by threefold.

Cement, salt and water: From Politecnico di Torino a new material toward green heat
A study carried out from the Turin university in collaboration with the Advanced Energy Technology Institute CNR-ITAE and published on the journal Scientific Reports, suggest a low cost technology to store heat during the summer and use it during the winter, thus saving in fossil fuels.

Cement-free concrete beats corrosion and gives fatbergs the flush
Researchers from RMIT University have developed an eco-friendly zero-cement concrete, which all but eliminates corrosion.

Self-healing bone cement
Material scientists at the University of Jena have developed a bone replacement based on calcium phosphate cement and reinforced with carbon fibers.

Chinese scientists optimize strontium content to improve bioactive bone cement
Researchers from the Shenzhen Institutes of Advanced Technology (SIAT) of the Chinese Academy of Sciences have developed a new strontium-substituted bioactive glass (BG) bone cement that optimizes the concentration of strontium to improve peri-implant bone formation and bone-implant contact.

'Wood' you like to recycle concrete?
Scientists at The University of Tokyo studied a method for recycling unused concrete with wood fibers.

Buildings can become a global CO2 sink if made out of wood instead of cement and steel
A material revolution replacing cement and steel in urban construction by wood can have double benefits for climate stabilization.

New optical technique captures real-time dynamics of cement setting
Researchers have developed a nondestructive and noninvasive optical technique that can determine the setting times for various types of cement paste, which is used to bind new and old concrete surfaces.

Read More: Cement News and Cement Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.