Featured Research

from universities, journals, and other organizations

Recycled Haitian concrete can be safe, strong and less expensive, researchers say

Date:
January 5, 2011
Source:
The American Ceramic Society
Summary:
Nearly one year after a 7.0-magnitude earthquake rocked the Republic of Haiti, engineering and concrete experts report that concrete and other debris in Port-au-Prince could be safely and inexpensively recycled into strong new construction material.

A new report finds that nearly one year after a 7.0-magnitude earthquake rocked the Republic of Haiti, concrete and other debris in Port-au-Prince can be safely and inexpensively recycled into strong new construction material.
Credit: ACerS Bulletin/Reginald DesRoches

Nearly one year after a 7.0-magnitude earthquake rocked the Republic of Haiti, engineering and concrete experts at Georgia Tech report that concrete and other debris in Port-au-Prince can be safely and inexpensively recycled into strong new construction material.

Related Articles


In a paper published in the Bulletin of the American Ceramic Society, researchers Reginald R. DesRoches, Kimberly E. Kurtis and Joshua J. Gresham say that they have made new concrete, from recycled rubble and other indigenous raw materials using simple techniques, which meets or exceeds the minimum strength standards used in the United States.

Most of the damaged areas of Haiti are still in ruins. The trio says their work points to a successful and sustainable strategy for managing an unprecedented amount of waste, estimated to be 20 million cubic yards.

"The commodious piles of concrete rubble and construction debris form huge impediments to reconstruction and are often contaminated," says DesRoches, professor and Associated Chair of Civil and Environmental Engineering at Georgia Tech. "There are political and economic dilemmas as well, but we have found we can turn one of the dilemmas -- the rubble -- into a solution via some fairly simple methods of recycling the rubble and debris into new concrete."

DesRoches, who was born in Haiti, traveled several times in 2010 to Port-au-Prince to gather samples of typical concrete rubble and additionally collect samples of two readily available sand types used as fine aggregates in some concrete preparation.

He and Gresham also studied the methods, tools and raw materials used by local laborers to make concrete mixes. DesRoches recalls they encountered no mixing trucks. "Instead, all of the construction crews were manually batching smaller amounts of concrete. Unfortunately, they were mixing volumes of materials 'by eye,' an unreliable practice that probably caused much of the poor construction and building failure during the earthquake," he says.

Before leaving, DesRoches and Gresham manually cast an initial set of standard 3-inch by 6-inch concrete test blocks using mixes from several different construction sites.

They returned to Georgia Tech with their cast blocks, sand samples and notes, where they were joined by Kurtis, also a professor and Chair of the American Concrete Institute's Materials Science of Concrete Committee.

They quickly discovered that the concrete test samples cast in Haiti were of poor quality. "The Haitian-made concrete had an average compressive strength of 1,300 pounds per square inch," says Kurtis. "In comparison, concrete produced in the U.S. would be expected to have a minimum strength of 3,000 pounds per square inch.

They then manually crushed the samples with a hammer to provide course aggregate for a second round of tests. In this round, they made concrete samples from mixes that combined the course aggregate with one of the two types of sands they had collected. However, instead of "eye-balling" the amounts of materials, in this round of tests they carefully measured volumes using methods prescribed by the American Concrete Institute. The materials were still mixed by hand to replicate the conditions in Haiti.

Subsequent tests of samples made from each type of sand provided good news: The compressive strength of both of the types of new test blocks, still composed of Haitian materials, dramatically increased, showing an average over 3,000 pounds per square inch.

"Based upon these results, we now believe that Haitian concrete debris, even of inferior quality, can be effectively used as recycled course aggregate in new construction," says Kurtis. "It can work effectively, even if mixed by hand. The key is having a consistent mix of materials that can be easily measured. We are confident are results can be scaled up mix procedure where quantities can be measured using common, inexpensive construction equipment."

DesRoches is pleased because recycling eliminates two hurdles to reconstruction. "First, removing the remaining debris is nearly impossible because there are few, if any, safe landfill sites near Port-au-Prince, and the nation lacks the trucks and infrastructure to haul it away. It is better to use it than to move it. "Second," DesRoches says, "Finding fresh aggregate is more difficult than getting rid of the debris. It is costly to find, mine and truck in."

The trio notes recycled concrete aggregate has been used worldwide for roadbeds, drainage, etc., and that many European Union countries commonly use 20 percent recycled aggregates in structural concrete. Published research by others has also demonstrated that the use of local-sourced recycled aggregate concrete production can be more sustainable.

Because of the urgency of quick and safe reconstruction, the researchers urge that recycling the debris quickly move from proof-of-concept to large scale testing. "More work must be done to characterize the recycled materials, test additional performance parameters and gauge the safest ways to crush the rubble. Seismic behavior and building codes must be studied. But, these tests can and should be done dynamically, during reconstruction, because the benefits can be so immediate and significant," says DesRoches.

DesRoches, Kurtis and Gresham say they plan on sharing their research with Haitian government officials and nongovernmental organizations working on reconstruction projects. DesRoches is hopeful that a debris strategy and infrastructure will eventually emerge from the government once the disputed presidential elections in Haiti are resolved. "Some think that many rebuilding projects have on hold for the past few months because of distraction from the elections. The next round of elections is this month, so it soon may be possible to accelerate reconstruction."


Story Source:

The above story is based on materials provided by The American Ceramic Society. Note: Materials may be edited for content and length.


Journal Reference:

  1. Reginald R. DesRoches, Kimberly E. Kurtis and Joshua J. Gresham. Breaking the reconstruction logjam: Haiti urged to recycle concrete rubble. Bulletin of the American Ceramic Society, 2011; 90 (1): 20-26

Cite This Page:

The American Ceramic Society. "Recycled Haitian concrete can be safe, strong and less expensive, researchers say." ScienceDaily. ScienceDaily, 5 January 2011. <www.sciencedaily.com/releases/2011/01/110104151141.htm>.
The American Ceramic Society. (2011, January 5). Recycled Haitian concrete can be safe, strong and less expensive, researchers say. ScienceDaily. Retrieved April 18, 2015 from www.sciencedaily.com/releases/2011/01/110104151141.htm
The American Ceramic Society. "Recycled Haitian concrete can be safe, strong and less expensive, researchers say." ScienceDaily. www.sciencedaily.com/releases/2011/01/110104151141.htm (accessed April 18, 2015).

Share This


More From ScienceDaily



More Matter & Energy News

Saturday, April 18, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

NASA Electric Rover Goes for a Spin

NASA Electric Rover Goes for a Spin

Reuters - Innovations Video Online (Apr. 17, 2015) NASA&apos;s prototype electric buggy could influence future space rovers and conventional cars. Jim Drury reports. Video provided by Reuters
Powered by NewsLook.com
Scientists Create Self-Powering Camera

Scientists Create Self-Powering Camera

Reuters - Innovations Video Online (Apr. 17, 2015) American scientists build a self-powering camera that captures images without using an external power source, allowing it to operate indefinitely in a well-lit environment. Elly Park reports. Video provided by Reuters
Powered by NewsLook.com
The State Of Virtual Reality

The State Of Virtual Reality

Newsy (Apr. 17, 2015) Virtual Reality is still a young industry. What’s on offer and what should we expect from our immersive new future? Video provided by Newsy
Powered by NewsLook.com
Tackling Congestion in the World's Worst Traffic City

Tackling Congestion in the World's Worst Traffic City

Reuters - News Video Online (Apr. 16, 2015) New transportation system and regulations aim to resolve gridlock in Jakarta, which has been named the city with the world&apos;s worst traffic. Angie Teo reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins