Study of the Properties of Fiber-Reinforced Concrete Using a Composite Binder Based on Portland Cement and Fly Ash from Thermal Power Plants

The influence of the amount of fly ash from thermal power plants in the composition of a composite binder on the technological and strength properties of concrete mixtures and concretes reinforced with polypropylene fiber has been studied. Fiber-reinforced concrete compositions with a fly ash content of 5, 10 and 15 % by weight of cement have been developed. The compositions of concretes with a fiber content of 400, 500 and 600 g/m³, as well as with a superplasticizer additive content in the range of 0,6–1 %, were studied. Mathematical processing of experimental data was performed using the Microsoft Excel and Mathcad software package. An analysis of the results showed that an increase in the fiber content reduces the mobility of the concrete mixture, and an increase in the amount of fly ash increases it. The maximum mobility value of 16 cm is fixed in the composition of concrete with a reduced fiber content and a maximum content of fly ash and superplasticizer additives. The flexural tensile strength is significantly affected by the fiber content in the concrete composition, and the effect of fly ash and superplasticizer content is not significant compared to the fiber content. The compressive strength of concrete at the age of 28 days is affected by the content of all three additives. The maximum value of 38,1 MPa is fixed in composition 2 with a maximum content of fibroblast and fly ash additives and a minimum content of superplasticizer additives. Studies have shown that the introduction of fly ash into the composition of fiber reinforced concrete makes it possible to obtain concretes with high strength characteristics.