Research of the strength of multicomponent cast concrete for the reconstruction and modernization of heat supply facilities of the city

Abstract

The application of multi-component cast concrete with the use of fly ash (waste material of thermal stations) in the reconstruction and modernization of facilities of generation and supply of thermal energy, which are part of engineering networks a belong to critical infrastructure, is considered.

Deals with the impact of mechanical activation on the change in strength characteristics of cast concrete on a cement-sol binder with the addition of fiber and plasticizing additives. The share of fly ash in the binder was taken from 0 to 80 %. C-3 superplasticizer was used to increase the performance of the concrete mixture. Bauson-basalt basalt fiber with a length of 6-12 mm and a diameter of 13-18 μm was a filler (it was dosed in a dry mixture). The preparation of the concrete mixture was carried out in a forced action laboratory mixer. Portland cement, fly ash and basalt fiber were dosed by weight. Two parallel series of experiments were performed (according to traditional technology; using mechanoactivation of the suspension). After mixing for 120 seconds, water with a dosed amount of the additive was introduced into the mixture. Concrete strength was determined for 7 and 28 days. A joint study of influencing factors - mechanical activation, fly ash, with a determined concentration of C-3 and basalt fiber, allows to increase the strength at the 28th day of age by 25-30 %.

The use of the studied cast concrete (with an increase in the content of fly ash in the binder by 15-20% without reducing the strength of concrete samples) allows to increase the efficiency of its use for monolithic ceilings of buildings and structures of heat generation and heat supply networks when implementing heat supply scenarios in schemes heat supply of cities, taking into account the formation of integrated heat networks.