Nanomodified Ultra High-Performance Fiber Reinforced Cementitious Composites with Enhanced Operational Characteristics

This study presents nanomodified ultra-high-performance fiber-reinforced cement composites, which are characterized by increased technical characteristics in extreme operating conditions. It is shown that the synergistic combination of mixtures based on Portland cement with high early strength CEM I, ultra fine zeolite, nano-SiO2, abrasive aggregate, basalt fibers using a superplasticizer of the polycarboxylate type allows obtaining rapid-hardening, high-intensity compounds. Such cementitios composites, after aging at temperatures up to T = 400 ℃ due to the phenomenon of self-autoclaving, are characterized by extremely high compressive strength (over 150 MPa), in this case low wear resistance is achieved—0.06 g/cm2, and that compounds acquire the characteristics of a chemically bonded ceramics In the cementitious composite, the amount of residual portlandite is 2.75% or 66 kg/m3, which meets the requirements for the strength index of UHPC. The high efficiency of cementitious composites is ensured by the creation of a monolithic dense structure at the meso-, micro- and nanostructural levels by improving the interphase interaction. It was established that as a result of the interaction of nano-SiO2 with calcium hydroxide in the cement paste, calcium hydrosilicates of the CSH(I) type are formed, which settle on the surface of fine-grained abrasive aggregate, that contributes to the strengthening of the contact zone. Nanomodified rapid-hardening ultra-high-strength fiber-reinforced cementitious composites can be used to create protective structures in industries where increased abrasion resistance at high temperatures is required, particularly in the coal, cement, metallurgical or mining industries.