Nanomodified rapid hardening concretes

Abstract

One of the priority areas of modern construction production is the introduction of high-performance high-speed concrete with improved technological and construction-technical properties for the design, erection and repair of engineering structures. Modern studies have made it possible to view concrete from the nanoscale point of view as a material characterized by a complex hetero-scale structure of hydrated cement phases and mineral additives. The properties of concrete are determined by the type, size and nature of the interaction of the components of each structural level, which creates the possibility of nanotechnological regulation of the processes of structure formation and control of operational characteristics. The main task of nanomodification is to provide managed structure with more nanoscale hydration products. Typical nanowires in Portland cement systems are micro- and nanosilica SiO2, nanoglosses, TiO2, Al2O3, Fe2O3, CaCO3, carbon nanomaterials (carbon nanotubes and nanofibers). The introduction of C-S-H nanoparticles is the most effective way of accelerating the hydration of cement compared to other nanowires, by ensuring the growth of hydration products without an energy barrier in the pore space between the cement grains. The presented studies are devoted to the study of the nanomodification efficiency of concrete with a complex additive containing a polycarboxylate superplasticizer and synthesized nanoscale C-S-H particles. Based on the analysis of the results of early and design strength of nanomodified concrete, it is established that it is characterized by rapid strength gain and high durability after 28 days. The construction and technical properties of nanomodified concretes were investigated after 1 and 28 days of curing.