چكيده به لاتين
Magnetite physical and chemical properties have many applications in industry. Nowadays concrete coatings are being considered as a material for streets, expressways and runways constructions.The purpose of this study is to investigate the effects of Magnetite as aggregate inside of the concrete mixtures to replace a small part of the cement in standard mortar mixture and perceive its mechanism and strength. In which by heeding the codes’ requirements Magnetite can be used in all studies. Magnetite advantages such as magnetic features, thermal energy absorption, thermal energy-saving and microwave absorption make can be used in road construction and asphalt mixtures. On the other hand, Magnetite has Noise regulation feature, the main feature of using Magnetite concrete mixtures to absorb sound waves in magnetite mixtures is investigated by a new method called impedance tube. At the beginning the specimens with the aggregates are replaced by Magnetite with following patterns: 0, 10, 20, 30, 40, 50 and after that 0, 2, 3.5, 5, 7.5, 10, 15 and 20 percent of the cement is replaced by Magnetite concentrate was made. Also, slump, density, flow table test, compressive strength, flexural strength, water absorption, electrical resistivity, and impedance tube was conducted. The results indicate that by adding magnetite aggregates the density of the concrete increases, the slump of the specimens decreases by 50% but still is in the standard zone. 28-day age flexural strength of the Magnetite concrete is the same as the reference specimens but with an incremental rate strength gaining against the reference specimens. However, the compressive strength of magnetite concrete indicates a 39% decrement decrement oppose to the reference specimens. The wearing and resistivity strengths decrease 24% and 61% compared to the reference specimens at 28-day age of magnetite concrete and in absorption tests the water absorption of the magnetite concrete specimens have a slightly more value in the first 6-hours of the test and for the next eight days there are some irregularities oppose to the reference specimens. Coefficient of sound absorption conducted by impedance tube test, shows that the coefficient of the magnetite concrete specimens has a more significant value oppose to the reference concrete specimens, Magnetite concrete specimens with 50% magnetite and 0.1 absorb coefficient in 315 to 400 frequency interval has the most value of the sound absorption in all of the specimens and 2.5 times larger than the sound absorbation maximum value of reference specimens.
