Basic Mechanical and Neutron Shielding Performance of Mortar Mixed with Boron Compounds with Various Alkalinity

This study conducted fundamental tests on mortars using the boron compounds recycled industrial wastes to replace uneconomic boron products. The boron compounds were three types according to the pH and the physical and neutron shielding performance of mortar mixed with boron compounds was examined. The adopted boron compounds classified as acid, slightly alkaline, and strongly alkaline with respect to the pH are acidic boric acid, alkali borax, and high alkali borax, respectively. The physical properties were evaluated by measuring the compressive strength and setting time as well as the thermal neutron shielding performance. The measured compressive strength revealed that the strengths of the specimens mixed with boron compounds were generally lower than that of the basic specimen made of control specimen. In addition, the initial and final setting times were longer than those of the control specimen. The thermal neutron shielding performances of the specimens mixed with boron compounds were higher than that of the control specimen. Consequently, the differences of the type and chemical composition of boron compounds influenced the physical properties and thermal neutron shielding performance of mortar, including its compressive strength, setting time, and neutron shielding performance. Therefore, it is important to determine the optimal amount of boron compounds in the fabrication of mortar.