SCMT4 Las Vegas, USA, August 7-11, 2016 Engineering Properties of Dredged Materials Stabilized with Fly Ash Hua Yu 1 , Jie Yin 2 , Ali Soleimanbeigi 3a , William J. Likos 3b , and Tuncer B. Edil 4 1 Civil and Architectural Engineering, University of Wyoming, Laramie, WY 82701, USA. Email: <hyu3@uwyo.edu> 2 Department of Civil engineering, Jiangsu University, Zhenjiang 212013, China. Email: <yinjie@ujs.edu.cn> 3 Geological Engineering Department, University of Wisconsin-Madison, Madison, WI 53706, USA. 3a Email: <soleimanbeig@wisc.edu>, 3b Email: <likos@wisc.edu> 4 Recycled Materials Resource Center-3 rd Generation (RMRC-3G), University of Wisconsin-Madison, Madison, WI 53706, USA. Email: <tbedil@wisc.edu> ABSTRACT A series of laboratory tests were conducted on the raw dredged materials (RDMs) stabilized with different fly ash contents (i.e., 10%, 20%, and 30%, by weight of dry soil) and curing times (i.e., 2 hours, 7 days, and 28 days). Results showed that increasing fly ash content decreased the plasticity index and improved engineering properties of RDM. Increasing fly ash content from 0% to 30% decreased the plasticity index from 19.3% to 9.5%, decreased the optimum water content from 30% to 23%, and increased the maximum dry unit weight from 12.9 kN/m 3 to 13.9 kN/m 3 . Both fly ash content and curing time affected engineering properties of stabilized dredged materials (SDMs). Increasing fly ash content from 0% to 30% at 28-day curing time increased the California bearing ratio (CBR) from 1.5 to 21.4, and increased the undrained shear strength from 240 kPa to 713.8 kPa. For specimens with 30% fly ash content, increasing curing time from 2 hours to 7 days resulted in an increase of CBR from 7.8 to 20.0 as well as an increase of undrained shear strength from 293 kPa to 499 kPa. From the results of this study, SDM with no less than 10% fly ash and curing time longer than 7 days content is recommended as subbase or subgrade fill in roadway construction. INTRODUCTION Around 300-million cubic yards of sediments have to be dredged in US to maintain or deepen navigation channels, anchorages or berthing areas for the safe passage of boats and ships [Childs 2015; Katsiaras et al. 2015]. Traditional dredging methods discharge sediments into oceans, rivers, lakes, wetlands, estuaries, or confined disposal facilities (CDFs). Particularly, about 2-3 million cubic yards of sediments are dredged annually in the Great Lakes Region and half of which are placed in CDFs. Meanwhile, many existing CDFs that serve ports are at or near their capacity [Clark and Knight 2013]. Beneficial use of raw dredged materials (RDMs) has become a viable alternative to traditional "dredge and dispose" methods [Childs 2015]. RDMs can be used for beach nourishment, capping, land creation and Fourth International Conference on Sustainable Construction Materials and Technologies http://www.claisse.info/Proceedings.htm