The concrete way of recycling rice

by Carol Truemner, reprinted from WEAL, the engineering faculty’s alumni newsletter

Most people wouldn’t associate digging into a bowl of steaming rice with driving under a concrete bridge. But Jeff West isn’t most people.

For the past five years the Waterloo civil and environmental engineering professor has been working with colleague Khaled Soudki, Canada Research Chair in Innovative Structural Rehabilitation, and a graduate student to research the idea of using rice husk ash (also called RHA) to give concrete special properties such a as high strength and durability. He’s also interested in making the concrete highly flowable or self-consolidating. He says while normal concrete is “kind of like ketchup,” meaning it doesn’t flow very well unless you squeeze or push or vibrate it, self-consolidating concrete mixed with RHA is just the opposite. It flows.

“This means it’s easy to place, you need fewer workers and you don’t need to vibrate the concrete. The quality is better too,” he says.

Now that his research results are in, that seems to be the case. RHA is an active pozzolan, which, when added to the cement in a concrete mix, reduces the number of pores or voids in the concrete when the RHA’s tiny particles react with water and cement hydration by-products. This improves both the strength and durability of the concrete.

Burning rice husks or hulls makes perfect financial and ecological sense. Rice covers one per cent of the earth’s surface and is an essential source of food for billions of people. By burning the hard protective coverings of rice grains, the resulting ash can be used for anything from fillers for concrete to insulation powder. Meanwhile, the actual husks show up in products including pet food, pillows, building materials and even beer.

Although West’s own research uncovered new areas of interest for concrete manufacturing, there were some concerns at first. RHA particles are minuscule – about 50 micrometres – and they’re angular. And angular particles do not necessarily rub against each other with ease. The result? A sticky, non-flowable mixture. Fortunately, with careful proportioning and by adding other admixtures, the self-consolidating concrete flowed. “In the end, it worked out very well,” says West.

West says some of his “really bright undergraduate students” also worked on some other exciting aspects of RHA. Specifically, they looked at what would happen to concrete if they simply replaced a percentage of cement with rice husk ash. “They found it works just fine. In fact, they even got some better properties,” he says. The result was concrete with equal or better characteristics at a lower cost since the amount of cement was reduced.

The possible ramifications for West and his students’ findings are huge for developing countries where rice husks are abundant and money for infrastructure is not. And no one can deny that the possibility of recycling rice husks to be used this way could have eco-friendly benefits especially if industry is willing to go one step further and harness the residual energy.

“Most of the time these rice husks were going to end up in the landfill anyway, “ says West. “So if we burn them, produce electricity while we’re burning them, and then use the ash in concrete, we end up the a double or triple benefit.”

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Superconductivity star visits nano institute

A world-leading authority in superconducting materials research will make a special visit next week to the Waterloo Institute for Nanotechnology.

Hideo Hosono (left), of the Frontier Research Centre and Materials and Structures Laboratory, Tokyo Institute of Technology, will spend a week at UW starting this Friday. In addition to visits and discussions, Hosono will deliver a special public lecture on superconductivity on Monday at 3:30 p.m. in Davis Centre room 1302.

Hosono's work was recently profiled in a Scientific American article entitled “An Iron Key to High-Temperature Superconductivity?"

"We are very excited” about the visit, says Arthur Carty, executive director of WIN. "Hosono has created great excitement in the science community by re-energizing the search for a ‘holy grail’ of materials research — the development of room-temperature superconductors."

In practical terms, superconductivity holds the key to such things as lossless electricity transmission (current transmission lines lose significant amounts of energy via heat loss), transportation via magnetic levitation and super-strong magnets for medical imaging. It is thought that many applications relating to energy use and conservation will ultimately be discovered through this research.

Hosono's presentation, entitled "New Frontiers of Materials Research: From Functional Transparent Oxides to High Temperature Superconductors", “will unlock the mystery of high temperature superconductivity,” Alain Francq of WIN says. The lecture is part of WIN's Distinguished Lecture series.

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'Welcome' events, Berlin pictures, and more

“Students can expect more events from the Federation of Students this fall,” says a news release that appeared yesterday from the Feds — the self-governing organization of 22,000 UW undergraduates. It goes on: “Students voted to increase the Federation of Students fee by one dollar in March to increase the social, spiritual, emotional, cultural, athletic and academic programming for undergraduate students. The Federation of Students is responding to these programming needs and has hired Laura McQuinn, Special Events Coordinator.” New programming starts with the current Welcome Week, designed “to bridge the gap between orientation week and life as a student”. Says McQuinn: “We are very excited about welcome week, which is different from orientation in two distinct ways. First, it is for all undergraduate students, not only first year students. Second, programming for the week begins when classes start in September, so students can continue meeting other students from different faculties creating a strong sense of community.” Feds executives “couldn’t be more pleased with this addition to our team,” says vice-president (administration and finance) Chris Neal, “and we’re excited to try new initiatives to engage students and support a strong and vibrant student life.” Welcome week events are continuing today with a Twitter-based “Amazing Race Scavenger Hunt” from 1 to 4 p.m. in the Student Life Centre and a movie night at Fed Hall: “Ghosts of Girlfriends Past”, showing at 8:00.

An exhibition of pictures from the flashpoint of the “cold war”, the Berlin Wall, opened this week in the art gallery of UW’s Modern Languages building and continues through October 3. An announcement from the Waterloo Centre for German Studies explains: “On November 9, 2009, Germany will celebrate the 20th anniversary of the fall of the Berlin Wall. The Goethe-Institute Toronto uses this occasion to bring the photo exhibition ‘Icons of a Border Installation’ to Canada and will present it at nine locations. A group of students from the University of Paderborn in Germany under the direction of Prof. Barbara Becker and the photographer Jürgen Spiler went to Berlin and searched for traces of the Berlin Wall.” During its visit to Waterloo, the show is open weekdays from 12:30 to 4:30; the gallery is in the foyer of the Theatre of the Arts. The Goethe-Institut San Francisco has put together a slide show of the exhibition.

UW’s Centre for Education in Mathematics and Computing, best known for the Canadian Mathematics Competition, has launched the Facebook group “Who is The Mathiest?”. High school students and mathies alike are challenged to post their video solutions online to the math problem of the week. Problem 1 is “The Checkerboard, the Dominoes and the Chickens”: can you cover the checkerboard with dominoes or prove that it?s impossible to cover? Solutions are due by this Friday. Coming later this fall are opportunities to solve more problems, to parody a popular song in math style, or to describe your favourite mathematician. Many high school students who are very strong at mathematics aren’t aware of the career opportunities awaiting math grads, organizers at CEMC say. The Facebook group will showcase some interesting applications of mathematics and mathies who have gone on to successful careers. Anybody interested in making a video appearance on this group can get in touch with Judith Koeller (jakoelle@ math.uwaterloo.ca).

Pies will be for sale in the Student Life Centre "vendors' alley" from 11:00 to 3:00 today as a fund-raiser for the local Arthritis Society, and serious gourmands will take part in a pie-eating contest at 2:00. • Dinner in the REVelation cafeteria in Ron Eydt Village will be a little different from the usual, with a "backyard barbecue" from 4:30 to 8:00. • The Waterloo Region Record newspaper took the unusual step yesterday of reprinting an entire story, its September 12 piece about UW's new United Arab Emirates campus that included a key error about whether women are permitted (yes they are).

CAR

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