Time-Variant Surface Chloride Concentration Analysis of Concrete Pavement Exposed to Road Salts

Funded by UNK Office of Sponsored Programs and Research Development


Project Summary

To reduce the risk of corrosion, many State Highway Agencies (SHAs) and organizations such as the American Concrete Institute (ACI) have limited the application of chlorides.  However, there is little consensus on the application rate of road salts to prevent the formation of ice on the roads without increasing the risk of corrosion. The reported application rate of road salts ranges from 0.5 tons/lane-mile in New Mexico to 19.4 tons/lane-mile in Massachusetts. This significant variation in the application rate of road salts can result in substantial risk of corrosion and scatter in the service lives of concrete roads and bridge decks.

This project looks into meeting the following objectives: (1) to determine how precipitation, ice deposition, evaporation, spray-off, and surface water run-off can affect the concentration of chlorides on the road surface in time; and (2) to develop a model to predict the chloride concentration on the road surface given meteorological data.

Effect of Corn Cob Ash on Corrosion-Resistance and Chloride Ion Permeability of Concrete

Funded by Nebraska EPSCoR

Project Summary

One common approach to manufacture a durable concrete is to reduce the permeability and increase the resistivity of the concrete against the movement of aggressive species such as chlorides into the hardened concrete. Toward this goal, the application of industrial by-products such as fly ash, silica fume, blast furnace slag, copper slag, and some of the agricultural by-product like palm oil shells, bagasse ash, elephant grass ash, wood waste ash, coconut shell ash, and rice husk ash have received a considerable attention in recent years.

This research studies the application of corn cob ash as supplementary material in concrete and evaluates its influence on the corrosion-resistance and chloride permeability of the concrete. Nebraska is the third largest producer of corn in the U.S. with the harvesting capacity of over 1.6 billion bushels of corn per year. Given that corn cob is an affordable and sustainable product in Nebraska, the application of this agricultural waste in the concrete industry contributes to a more durable and sustainable society and infrastructure.


Use of Lignocellulosic Biomass Wastes as Portland Cement Replacement Materials in Concrete

Funded by UNK Office of Sponsored Programs and Research Development


Project Summary

Since 2005, coal’s share of electricity generation has declined at a steady clip.  With energy trends resulting in a move away from coal-fired plants in recent years, the availability of coal-based ashes like fly ash has been significantly reduced, resulting in many regions throughout the US experiencing reduced availability of fly ash. The shortage of fly ash has presented a challenge in the construction industry, and this shortage has resulted in the production of less sustainable concrete that exhibits reduced durability and resiliency characteristics.

Given the recent reductions in the supply of fly ash and the pressing need to build durable and resilient infrastructure, it is essential to look for alternative supplementary materials as a replacement for fly ash. This project looks into the potential application of LBW as an alternative cementing material for concrete. To this end, this project will investigate the application of one of the important feedstocks, namely, corn stover in the concrete industry.

Multiscale-Multiphysics Modeling of Corrosion-Induced Damage in Structural Tendons

Funded by University of Nebraska System Science

Project Summary

Chloride-induced corrosion is one of the most prevalent forms of corrosion in the reinforced concrete structures. Considering that the vast number of concrete bridges in the US are prestressed, particular attention should be paid to the mechanisms and factors that influence the corrosion of prestressed tendons in concrete. Because corrosion initiation and propagation are accelerated under stress, and given that corrosion of prestressing steel, under certain conditions, is not visible at the concrete surface, corrosion of prestressed structures is often detected when it is too late and the structure has incurred irreversible damages.

This project which is done in collaboration with UNL and UNO looks at the role of chlorides and sulfates in the electrochemical process of prestressing strand corrosion in grouts. 


Multi-Scale Study of Cellular Concrete Tailored with Time-Dependent Rheological Behavior

Funded by University of Nebraska System Science


Project Summary

The long-term objectives of this collaborative research are to generate critical knowledge for rational control and fundamental understanding of cellular concrete and expand the knowledge to other highly porous materials such as porous ceramics, aluminum foam, and artificial bones, and broaden their use in different applications. The study combines basic and
applied research to establish sound design and construction practices for novel cellular concrete. The success of the study will establish the research team as a leader in modeling and simulation of failure in cellular concrete and its applications. 

Developing a secure wireless sensor for applications in remote infrastructure monitoring

Funded by University of Nebraska System Science

Project Summary

The objective of this multidisciplinary study is to improve the reliability of wireless sensors by improving security issues and interference problems and designing from the beginning with these issues in mind. Overcoming such barriers will produce new opportunities for fields like quality control and assurance in construction; and wireless sensor applications in healthcare and safety. Two specific areas in which these sensors can be beneficial to the industry are (i) measuring the concentration of the chlorides at a depth of the reinforcing steel; and (ii) ongoing monitoring of the potential of the embedded reinforcing steel in concrete.


Developing an alternative cementitious material from raw corn stover and bioethanol
production plants’ waste products

Funded by University of Nebraska System Science


Project Summary

The proposed research leverages the local and replenishable resources of agricultural wastes to minimize the environmental impacts of the concrete industry. The specific objectives of this research are to: 

  1. develop a comprehensive database on the physical and chemical properties of the ashes that can be produced from (a) raw field corn stover, and (b) processed field corn seed wastes obtained from ethanol plants that are located in Nebraska, Iowa, and Illinois,

  2. develop a standardized and optimized ashing protocol (including pre and postprocessing) to produce high-quality corn ash; and

  3. perform multiscale-multiphysics tests on the rheological, mechanical, and durability properties of concrete mixtures and develop an optimized concrete mixture design protocol.


Beneficial reuse of landfilled fly ash in transportation infrastructure


Project Summary

According to a recent survey by the American Coal Ash Association (ACAA), approximately 38 million tons of fly ash were produced in 2017 and about 14 million tons of which were used in concrete. The rest of 24 million tons of fly ash were disposed in landfills. The ACAA estimates that the gap between demand and supply of concrete-grade fly ash is about 25% nationally. Shortages are being driven by the retirement and capacity reductions of coal-fired power plants and the move toward natural gas and renewable energy sources. It is anticipated that future shortages in fly ash will be more significant in the near future.

In this study, researchers from Colorado State University and the University of Wyoming will work jointly with the concrete industry partners in the region to understand the role that landfilled fly ash plays in controlling concrete properties in the fresh and hardened state. Thus, it is imperative to understand how (1) the physiochemical properties, (2) unburned carbon content, and (3) reactivity of landfilled fly as, as opposed to ASTM-grade fly ash, influence the chemistry, rheology, strength, and durability of concrete.