Studying the Behavior and the Freezing Endurance of Heavy Concrete with Nano-Silica Gel and Ilmenite Powder in Different Volume Ratios

Basically, heavy concrete has the specific weight of about 1.5 to 2.5 times of the normal concrete. Materials with high specific weight are employed as a part of used aggregate to make heavy concrete. Heavy concrete is utilized as a protective shield against radiation. Heavy concrete is applied in the structure of nuclear infrastructures or hospitals. Ilmenite is a type of mineral that is also considered as mineral waste. Ilmenite is extracted directly from titanium mine and is found plentifully in Iran. In this study, Ilmenite is used in different volume ratios of 10%, 20%, 30%, and 40% instead of sand to make heavy concrete. Moreover, nano-silica gel, is used at the rate of 1% by weight of cement, to increase the quality and durability of concrete against the cycle of melting and freezing. The tests performed in this research include compressive strength test, tensile strength test, defining the primary and secondary water absorption rate and determination of concrete melting and freezing durability, according to ASTM-C666 standard. Results depicted that, the specific weight of heavy concrete would meet the regulations, by adding at least 20% of ilmenite instead of sand in concrete mixture. Also, adding 30% by volume of ilmenite, instead of sand, will increase the final compressive strength (90 days) by 33%. Finally, applying nano-silica gel in the heavy concrete mixture, makes the concrete stable against the melting and freezing cycles.