Humanitarian Materials Engineering

Esther Obonyo calls herself a Nairobi girl. The former interim director of Penn State’s Humanitarian Engineering and Social Entrepreneurship (HESE) program and Penn State’s Inaugural Global Faculty Fellow is relatively new to Penn State but has long research ties to Africa and particularly to Nairobi, Kenya, where she was raised and where she earned her initial degree, in building economics (Quantity Surveying). Following graduation from University of Nairobi, Obonyo worked for an American construction company in Kenya before moving to England to further her education. She earned a Masters in architecture and a Ph.D. in civil and building engineering. She then went to work in the private sector in the innovation department of a large multinational construction firm. She is an associate professor of engineering design and architectural engineering. Prior to that she was at the University of Florida.

This combination of training and work experience has given her a rather rare perspective on what is needed to overcome barriers to solving the large-scale building deficit in African countries.

“The big problem, in my opinion, is that the pathway to scale has still not been identified,” Obonyo says. “Nobody has said ‘Here is the solution, and we can repeat it at the scale of say, 100,000 or a million.’”

Because her training and professional experience straddle the architectural design and the building engineering divide, she can bring an analytical perspective to a design challenge. In addition, experience working in collaboration with local business and governmental organizations makes the financial and regulatory aspects of introducing new building materials more tractable.

Since 2008, Obonyo has been doing research in sustainable structural materials for building applications in both Kenya and Tanzania.

“Whenever I come to Kenya, I have the same question in my mind. A lot of people have done research on affordable building technology and building materials, but none of it seems to have had an impact,” she says. “We can just say we are not going to solve this, or we can go ahead and try looking at it from another perspective.”

A big issue, according to the local professionals she has met in Nairobi, was the requirement that nonconventional materials comply with building codes. That provided an opportunity for Obonyo and her colleagues, because questions of strength and durability can be tested.  

“The construction industry has a problem incorporating new materials because we can’t demonstrate compliance with the existing provisions of building code that were written with time-tested materials such as concrete,” she says. “That’s something we can investigate through a basic science approach.”

There is some empirical data demonstrating that if the unconventional material, primarily soil, is designed properly and scientific measurements are made to inform the inclusion of binders and other additives, they can be used to make affordable building materials that can perform up to code. Nevertheless, they are seeing some mixed results, some of which could be attributed to process-related factors.

For example, most tests in the field are based on rules of thumb that have been in use for a hundred years. One rule that has a scientific basis is not to use the top layer of soil because the surface layer is high in organic material. The testing method typically used for quality control is to put the soil in water in a bottle, shake it, and see how the various particles break down. Such tests work fine for understanding from a big picture perspective if the clay/ sand content is adequate. This test will not provide the sort of information that is necessary to make a decision on whether to use cement and/or lime as a binder. Some of the reported variations in the performance of the non-conventional materials can be attributed to the lack of soil-DNA type of information.  

“There are people making low cost houses with non-conventional materials like these, and it works just fine for meeting the needs of, say, 250 to 500 people,” she says. “But these processes cannot be easily translated into sustainable housing solutions at scale. If we are going to produce the amount of brick we need to reduce the current housing deficit, then we need cross-disciplinary thinking.”

Humanitarian Engineering

Cross-disciplinarity is a hallmark of the HESE program at Penn State, which draws its students from across the university. Typically, about half the students are in engineering, with the rest spread across the other colleges. In May, Obonyo and Dr. Sarah Ritter, a faculty member from the Engineering Design program, took a group of 17 students to Arusha, a city of around half a million located in northern Tanzania, for a three-week work experience.

“Before going, the students do guided research in a hands-on, studio-like setting. I provided a lot of background information to level the playing field for them given that the HESE program is by design a melting point of students from different academic backgrounds,” Obonyo says.

The cross-disciplinarity in HESE is exemplified in one student projects that focused on food security, specifically, building facilities for storage and distribution of food that otherwise might be wasted through spoilage. This was inspired by her experiences as a Jefferson Science Fellow in Washington, D.C.

“We largely talk about food insecurity in terms of producing more food, yet there is a large amount of food wasted through post-harvest loss because of the lack of adequate storage facilities,” says Obonyo. “So, for one of the student projects I wanted them to look at the opportunity of creating a low-cost storage facility that leverages the properties of organic building materials and other passive design techniques.”

Organic roofing material is known to passively cool a building’s interior. The walls were made 80 percent of earth and 20 percent or less of concrete. There is an additional ecological benefit here. Concrete is too expensive for many to afford, and its processing is a major contributor to greenhouse gas in the atmosphere.

“The students spent the Spring semester using an engineering design process to scope the project,” Obonyo explains. “They came up with some proofs of concept and during the three weeks of Maymester 2017, we travelled to Arusha to test and validate the concepts. For the post-harvest loss, this was partly done through the construction of a passively ventilated unit. Although we didn’t have time to finish the structure, by the time we left it was evident to everyone that the temperature inside the four walls minus the roof was significantly lower than outside.”

Another hallmark of the HESE program is working with locals to create sustainable long-term solutions. From the beginning, Obonyo was in regular communication with people in Arusha, putting options in front of them and soliciting feedback and opinions. Understanding cultural norms and practices is made easier for her by knowing the language, but it is also important for the students to spend as much time as possible interacting with local people. “You start to pick up unspoken things,” she suggests. “My East African people communicate a lot of things through the use of the unspoken word.”

Working with materials scientists

“When I came to Penn State, I already had this niche in mind that there is a role that science and technology can play in addressing societal problems,” Obonyo says. “In business, the biggest barrier I saw to sustainable solutions at scale was lack of quantifiable knowledge. I did my Ph.D. in intelligent systems and data mining. I still use it in my research. But it’s all part of knowledge management, knowledge distribution.”

She has experience working with materials scientists in testing samples she has brought back from East Africa, but she wants to expand that into other areas. With the support of the Materials Research Institute, she has begun a project with the chancellor of Penn State New Kensington to retrofit several historical buildings using lower cost, innovative materials.

They are exploring several options that can optimize the hygrothermal (heat and moisture) performance of the roofing element in a way that contributes to the goal of energy-efficient building systems at a neighborhood level.

“We need to be able to replicate this at large scale in order to affect an entire community. There may be 100 buildings that need help in a rapid and cost-effective way,” she says. “But it’s like Tanzania or Kenya, you have to ensure that the material you come up with complies with building codes. And when retrofitting something that is already damaged, how do you ensure that the solution is not going to deteriorate rapidly? That requires a multidisciplinary approach. I hope to have a long, 30-year relation with materials science.”

For further information about Prof. Obonyo’s research, contact her at