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Title: Setting and Stiffening of Cementitious Components in Cast Stone Waste Form for Disposal of Secondary Wastes from the Hanford waste treatment and immobilization plant

Abstract

Cast stone is a cementitious waste form, a viable option to immobilize secondary nuclear liquid wastes generated from Hanford vitrification plant. While the strength and radioactive technetium leaching of different waste form candidates have been reported, no study has been performed to understand the flow and stiffening behavior of Cast Stone, which is essential to ensure the proper workability, especially considering necessary safety as a nuclear waste form in a field scale application. The rheological and ultrasonic wave reflection (UWR) measurements were used to understand the setting and stiffening Cast Stone batches. X-ray diffraction (XRD) was used to find the correlation between specific phase formation and the stiffening of the paste. Our results showed good correlation between rheological properties of the fresh Cast Stone mixture and phase formation during hydration of Cast Stone. Secondary gypsum formation originating from blast furnace slag was observed in Cast Stone made with low concentration simulants. The formation of gypsum was suppressed in high concentration simulants. It was found that the stiffening of Cast Stone was strongly dependent on the concentration of simulant. A threshold concentration for the drastic change in stiffening was found at 1.56 M Na concentration.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1073553
Report Number(s):
PNNL-SA-82906
830403000
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Cement and Concrete Research, 46:14-22
Additional Journal Information:
Journal Name: Cement and Concrete Research, 46:14-22
Country of Publication:
United States
Language:
English
Subject:
Ultrasonic wave reflection; rheology; X-ray diffraction; stiffening; setting; nuclear waste

Citation Formats

Chung, Chul-Woo, Chun, Jaehun, Um, Wooyong, Sundaram, S. K., and Westsik, Joseph H. Setting and Stiffening of Cementitious Components in Cast Stone Waste Form for Disposal of Secondary Wastes from the Hanford waste treatment and immobilization plant. United States: N. p., 2013. Web. doi:10.1016/j.cemconres.2013.01.003.
Chung, Chul-Woo, Chun, Jaehun, Um, Wooyong, Sundaram, S. K., & Westsik, Joseph H. Setting and Stiffening of Cementitious Components in Cast Stone Waste Form for Disposal of Secondary Wastes from the Hanford waste treatment and immobilization plant. United States. doi:10.1016/j.cemconres.2013.01.003.
Chung, Chul-Woo, Chun, Jaehun, Um, Wooyong, Sundaram, S. K., and Westsik, Joseph H. Mon . "Setting and Stiffening of Cementitious Components in Cast Stone Waste Form for Disposal of Secondary Wastes from the Hanford waste treatment and immobilization plant". United States. doi:10.1016/j.cemconres.2013.01.003.
@article{osti_1073553,
title = {Setting and Stiffening of Cementitious Components in Cast Stone Waste Form for Disposal of Secondary Wastes from the Hanford waste treatment and immobilization plant},
author = {Chung, Chul-Woo and Chun, Jaehun and Um, Wooyong and Sundaram, S. K. and Westsik, Joseph H.},
abstractNote = {Cast stone is a cementitious waste form, a viable option to immobilize secondary nuclear liquid wastes generated from Hanford vitrification plant. While the strength and radioactive technetium leaching of different waste form candidates have been reported, no study has been performed to understand the flow and stiffening behavior of Cast Stone, which is essential to ensure the proper workability, especially considering necessary safety as a nuclear waste form in a field scale application. The rheological and ultrasonic wave reflection (UWR) measurements were used to understand the setting and stiffening Cast Stone batches. X-ray diffraction (XRD) was used to find the correlation between specific phase formation and the stiffening of the paste. Our results showed good correlation between rheological properties of the fresh Cast Stone mixture and phase formation during hydration of Cast Stone. Secondary gypsum formation originating from blast furnace slag was observed in Cast Stone made with low concentration simulants. The formation of gypsum was suppressed in high concentration simulants. It was found that the stiffening of Cast Stone was strongly dependent on the concentration of simulant. A threshold concentration for the drastic change in stiffening was found at 1.56 M Na concentration.},
doi = {10.1016/j.cemconres.2013.01.003},
journal = {Cement and Concrete Research, 46:14-22},
number = ,
volume = ,
place = {United States},
year = {2013},
month = {4}
}