Development of chemical-physical treatment of cement paste for reduction of dismantled radioactive concrete volume. (30th April 2020)

• Record Type: Journal Article
• Authors: Kim, Sunghak; Jang, Indong; Yi, Chongku
• Is Part Of: Construction & building materials. Volume 241(2020)
• Publication Date: 2020-04-30
• Subjects: Cement paste -- Acid treatment -- Ultrasonication -- Radioactive waste -- Waste management; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2020.118056
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: The effect of acid treatment on the weight loss of cement-paste specimens was investigated. The relation between the weight loss of cement paste and immersion time was derived. A new treatment scheme for removing cement paste from recycled fine aggregates was proposed. Abstract: To reduce the amount of radioactive concrete produced during the dismantling of nuclear power plants, it is essential to remove cement paste attached to aggregates. In this study, the effectiveness of a chemical and physical treatment for cement paste removal was evaluated. Cement-paste specimens having similar size to fine aggregate were treated in a sulfuric acid solution with ultrasonication. The weight loss of the specimens was measured to quantify the degree of decomposition of the cement paste. Scanning electron microscopy, surface hardness test, and inductively coupled plasma analysis were performed to identify the effect of acid treatment on the cement-paste specimens. The results indicated that the cement paste removal is associated with progressive degradation of near-surface layer, and the process can be accurately controlled as a function of water-cement ratio and specimen dimension. The findings are expected to be of great use to disposal of radioactive concrete.