Effect of microsilica supplement on workability and density of equally moveable flow concrete and concrete strength

The article examines the possibility of improving the concrete composition, by introducing the component of microsilica, in order to reduce the consumption of cement in concrete and, consequently, its cost. The result of using a mixture based on Portland slag cement (M 400) of Magnitogorsk Cement and Refractory Plant is described. The composition of concrete also included the following: porphyritic gravel GOP MMK fraction 10 - 20 mm; sand river fraction 0,16 - 5 mm; mixing water from the municipal water supply system and microsilica of the Chelyabinsk electrometallurgical plant with SiO2 content of 65- 83.38%. The authors reviewed the effect of microsilica on the strength of equally moveable concrete and the effect of microsilica on the properties of equally moveable mixtures and concrete. It was found that the addition of microsilica in an amount of 5 ... 15% of the weight of cement density of equally mobile, including concrete decreases by 80 ... 85 kg/m3; mix workability decreases from 5 to 0 cm; the strength of the concrete increases by 45 ... 90% – for steamed concrete; and by 19 ... 40% – for concrete hardening in normal conditions. According to the work results, saving of cement in concrete of B15...B25 class due to the introduction of microsilica may amount to 41 to 183 kg/m3, depending on curing conditions and the properties of concrete mixtures. The authors conclude that there are real prerequisites for the systematic organization of industrial production of new thermal insulation materials on an industrial scale using regional resources.