Influence of gadolinium oxide and ulexite on cement hydration and technical properties of mortars for neutron radiation shielding purposes

• Published in: Construction & building materials Vol. 195; pp. 583 - 589
• Main Authors: Piotrowski, Tomasz, Glinicka, Julia, Glinicki, Michał A., Prochoń, Piotr
• Format: Journal Article Web Resource
• Language: English
• Published: Elsevier Ltd 20.01.2019
• Subjects: Bending strength; Borate minerals; Boron compounds; Calorimeters; Calorimetry; Cement based composites; Civil engineering; Compressive strength; Engineering, computing & technology; Gadolinium compounds; Gadolinium oxide; Hydration; Hydration kinetics; Hydration of cements; Ingénierie civile; Ingénierie, informatique & technologie; Isothermal calorimetry; Isotherms; Mortar; Neutron irradiation; Neutron radiation; Neutron radiations; Neutrons; Portland cement; Radiation shielding; Radioactive waste; Radioactive wastes; Sodium Aluminate; Technical properties; Water to cement (binder) ratios; Bending strength; Neutron radiation; Radioactive waste; Mortar; Radiation shielding; Compressive strength; Boron compounds; Isothermal calorimetry; Gadolinium oxide
• ISSN: 0950-0618; 1879-0526; 1879-0526
• DOI: 10.1016/j.conbuildmat.2018.11.076

•Gadolinium oxide generates a slight retardation of cement hydration.•Gadolinium oxide increases hydration intensity by aluminate activity acceleration.•Gadolinium oxide optimum content is 5% in relation to the mass of cement.•A substantial content of ulexite hinders almost completely the cement hydration.•Good long term performance were obtained also for specimens with 3% of ulexite. Gadolinium oxide (Gd2O3) is a potentially effective mineral additive that improves neutron shielding properties of cement based composites. The paper presents the influence of Gd2O3 and ulexite (a boron compound) on Portland cement hydration evaluated by isothermal calorimetry measurements and strength. The progress of hydration was investigated on mortar specimens at water to cement ratio w/c = 0.5 and sand/cement ratio 0.75. The addition of Gd2O3 generates a slight retardation of cement hydration, however it accelerates aluminate activity at the same time. The hydration of cement was completely hindered for mortars containing a substantial content of ulexite. The strength test results show that addition of Gd2O3 to Portland cement mortar mix caused a decrease of early age (3 days) flexural and compressive strength. The optimum content of Gd2O3 in respect to the long term compressive strength and the hydration kinetics was 5% in relation to the mass of cement. Good long term strength was also obtained for specimens with 3% of ulexite.