Mechanical and physical characterization of cement reinforced by iron slag and titanate nanofibers to produce advanced containment for radioactive waste

• Published in: Construction & building materials Vol. 200; pp. 135 - 145
• Main Authors: Saleh, Hosam M., El-Sheikh, Said M., Elshereafy, Elsayed E., Essa, Adel K.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 10.03.2019; Reed Business Information, Inc. (US)
• Subjects: Analysis; Cement industry; Cements (Building materials); Cesium; Iron slag; Mechanical integrity; Mechanical properties; Nuclear energy; Nuclear environmental management; Porosity; Portland cement; Radioactive pollution; Radioactive wastes; Titanate nanofibers; Waste stabilization; Workability; Egypt; Radioactive wastes; Waste stabilization; Mechanical integrity; Titanate nanofibers; Porosity; Iron slag; Portland cement
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2018.12.100

[Display omitted] •Improvement of cement by titanate nanofibers to stabilize radioactive waste.•Titanate nanofibers enhance the mechanical properties of cement pastes.•By-products such as iron slag improve the integrity of cement pastes.•Mechanical and physical evaluation of cement pastes modified by titanate nanofibers. Based on the specific features of cement-derived materials gained by incorporation of nanomaterials, such as proper workability and accelerated hydration reaction, investigations of nano-modification of cementitious materials are increasingly conducted globally. In this study, locally manufactured cement was reinforced by optimized additions of iron slag (Granulated blast furnace slag) and titanate nanofibers to improve the basic mechanical, chemical and physical parameters of cement. These parameters were studied by investigating of the compressive strength and porosity of the produced materials. Moreover, the capacity of titanate nanofibers, which were studied in details by TEM and XRD, for absorption of radio-cesium was also investigated; more than 27% removal of radionuclides was achieved during 48 h in artificially contaminated wastewater in a broad pH- and temperature range of 3–11 and 0–50 °C, respectively. Spectroscopic analyses (FT-IR) were performed to confirm and investigate the results of mechanical integrity measurement of the new composite materials, while X-ray diffraction analysis provided information on the formation of hydration products. As major result, it turned out that a small amount of only 0.04% of titanate nanofibers in presence of 6 wt% slag relative to cement not only increases the strength of the hardened cement blocks by 14%; beyond that, it performs beneficial in terms of compression resistance and durability, and successfully captures radionuclides from the contaminated aqueous solution before the immobilization process.