Research Projects

Scope and Goals:

Civil infrastructure is and continues to be the backbone of our society to meet our needs in housing, transportation, water and electricity supply, and so on. However, in response to rising public concerns about sustainable and resilient infrastructure development, its functions are recently revisited to encompass roles beyond providing basic services. This leads to an unprecedented demand for environmentally low-impact (both energy and CO2 footprints) and resilient (both natural and man- made disasters) infrastructures. The many decades of civil and environmental engineering (CEE) practice highlight the importance of developing the next generation of construction materials to meet these expectations. In fact, understanding the fundamental issues of present materials and finding relevant cost-effective solutions is one of the greatest challenges ahead of contemporary CEE. The primary focus of our research group is to establish holistic multiscale frameworks (see figure below) to quantitatively address our national sustainability needs. In addition, we construct mechanistic-based approaches to quantitatively assess the large-scale environmental impacts of innovative material solutions.

Materials Research:

scales

Our research interest lies within the broad area of applied physics of construction materials. This multidisciplinary field is at the interface of physics, chemistry, materials science and solid mechanics. To this end, we employ tools of statistical physics and engineering mechanics to develop predictive tools for optimizing physical properties of materials such as concrete, phononic crystals, glasses and ceramics. For instance, cement paste, the glue of concrete, is a multiscale porous material that exhibits distinct physical features at multiple length scales. While its nanoscale and microscale properties are well studied, its mesoscale (10-100 nm) attributes cannot be addressed via conventional physics and mechanics approaches. In fact, meso-scale is neither small enough to use particle physics approaches nor large enough to employ mean-field homogenization theories to investigate its physical aspects. There are many intriguing questions regarding the texture of C-S-H at the mesoscale and its implications on physical properties of the cement paste that our team tries to answer in close collaboration with our experimental colleagues.

City-Scale Research:

energy

At the system level, it is not always straightforward to discern the fundamental cause of an infrastructure dilemma. A tangible example the energy efficiency of cities in the United States. According to a recent survey, 44% of energy consumption in buildings is used for space heating and cooling which accounts for 20% of the na- tional CO2 emissions. Currently, the White House seeks approaches to lower energy consumption of buildings by 40% and reduce the associated greenhouse gas emissions by 150 million metric tons till 2020. However, as it turns out, several factors affect energy use in buildings, such as human behavior, thermal characteristics of building’s envelope, HVAC systems, and many others. Therefore, it is imperative to have a quantitative understanding of influential parameters and their impact on network level properties prior to embarking on a specific approach. For instance, is it cost-effective to improve the thermal resis- tance of insulation materials among hundreds of other factors for retrofit purposes? If so, how much decrease in thermal conductance would have a meaningful impact on energy consumption at city scale? Over the course of our research, we have grown special fondness for these class of problems as they naturally highlight where we should concentrate our research efforts.