Use of Rice Husk Ash (RHA) as Stabilizing Agent for Poor Subgrade Soils and Embankments

Project Details









Momen Mousa, Zahid Hossain, Rifat Bulut


Office of the Assistant Secretary of Research and Technology


Embankments, Feasibility analysis, Soil stabilization, Subgrade materials, Waste products (Materials)

Project description

Arkansas produces the largest amount of rice in the United States. About 20% of the paddy is rice hull (RH). When burnt, 20% of RH is transformed into rice husk ash (RHA). Riceland Foods Inc., a family farmer-owned business in Arkansas, is the largest rice miller in the U.S. with an annual production of about 100 million bushels. A significant portion of RHA generated by Riceland is being treated as waste. RHA is a cementitious material, and Riceland's RHA contains about 75% silica in an amorphous form and has an extremely high surface area. RHA is also economically beneficial in stabilizing poor subgrade soils and embankments, but its performance as a construction material has been investigated very little. RHA can potentially be used as a stabilizing agent for poor subgrade and embankment soils, which are very common in Arkansas, Oklahoma, and other states. The main objective of the proposed collaborative study between Arkansas State University (A-State) and Oklahoma State University (OSU) is to assess the feasibility of the use of RHA in stabilizing poor subgrade and embankment soils through laboratory investigation. Based on the laboratory testing and results of this project, the investigators of this project will have a good understanding of the important features and efficacy of RHA as a stabilizing agent for poor soils. In particular, if there are short-term and long-term reactions, whether there are new minerals form as a result of the reactions, and whether the stabilization/modification processes are temporary or permanent will be understood. The outcome of the proposed study is expected to be important in setting the direction of the sustainable use of RHA and be a significant cost saving for transportation agencies in Region 6, which consists of Arkansas, Oklahoma, Louisiana, Texas, and New Mexico. In the long run, the outcomes of the proposed study will help local farmers to be economically sustainable as they are striving to find new markets for RHA. Furthermore, the A-State and OSU teams would like to utilize their resources and expertise in a unified and close collaboration way in maximizing the research outcome for likely adoption of this industrial by-product by transportation departments and other agencies within Region 6, and across the US. Therefore, a quite comprehensive and detailed study is proposed by both universities. This study will develop tools and materials for longer-lasting infrastructure, assess the feasibility of using local industry-generated RHA in the Mississippi Delta area, and establish strong collaborative records among partner institutions and local industries in the region. The benefits of the proposed study are multifold: (a) reuse of waste materials in transportation construction projects, (b) enhance training opportunities for students in the region, (c) help local farmers to be economically sustainable in the long run, (d) establish a new collaborative partnership with two major universities in Region 6, and (e) build a future workforce. This study supports multiple focus areas of Tran-SET: (1) Improving durability and extending the life of the infrastructure; (2) Preserving the environment; and (3) Other Regional priorities. The proposed study is aligned with a FAST track regional priority “Multiscale characterization of recyclable waste materials in transportation applications for achieving economical and material sustainability,” having a primary focus of “Recycling infrastructure assets.” RHA is a locally available waster material, which can be used to improve the quality of local materials, which are typically poor to withstand increasing traffic loads and extreme environmental events. On the other hand, RHA causes huge environmental burdens. Besides regional priorities, this project strongly supports the Center’s FAST focus areas 4 and 5.