Title: Workability and Mechanical Properties of Heavyweight Magnetite Concrete
Author(s): Keun-Hyeok Yang, Jae-Sung Mun, and Ho Lee
Publication: Materials Journal
Appears on pages(s): 273-282
Keywords: code equations; concrete density; heavyweight concrete; magnetite; mechanical properties
To provide basic data for developing mixing details and design models for structural heavyweight magnetite concrete, 18 concrete mixtures were prepared under different replacement levels with natural sand and granite coarse particles for magnetite fine and coarse aggregates, respectively. The density of concrete ranged between 3182 and 3400 kg/m3 (197.28 and 210.8 lb/ft3) for replacement by natural sand, and 2446 and 3118 kg/m3 (151.65 and 193.31 lb/ft3) for replacement by granite coarse particles. Test results revealed that the replacement by natural sand was preferable to that by granite coarse particles for enhancing the initial slump, tensile resistance capacity, shear strength and bond behavior with a reinforcing bar of heavyweight magnetite concrete, and for minimizing the decrease in concrete density due to replacement by normalweight aggregates. ACI 349 equations for moduli of elasticity and rupture were generally conservative for heavyweight magnetite concrete. The CEB-FIP equations were not conservative for the moduli of elasticity and rupture, strain at the peak stress, and splitting tensile strength of heavyweight magnetite concrete, whereas they were conservative in predicting the bond stress-slip response of heavyweight magnetite concrete. Overall, it can be concluded that the density of concrete should be considered as a critical factor, together with its compressive strength, in determining the various mechanical properties of heavyweight concrete.