Nanoscale Control of Hydrated Portland Cement Structure

Abstract

The durability of cement-containing building materials, like the cement stone itself, depends on their moisture resistance, frost resistance, and corrosion resistance. All these properties are determined not only by the composition of the initial clinker, but also by the structural organization at the micro-and nanoscale of hydrated Portland cement. In this work, the structural parameters of hydrated Portland cement compositions at the nanoscale level were determined by the method of small-angle neutron scattering: the size distribution of nanoparticles of calcium silicate hydrate, the average radius of nanoparticles, and fractal dimension. It is shown that the introduction of modifying nanoadditives into Portland cement affects the structural parameters of the cement stone. The following nanoadditives were used: of artificial (alpha aluminium oxide, gamma aluminum oxide) and of technogenic (carbonate and alumo-alkaline sludges) origin, as well as complex nanoadditives containing surfactants. Changes in structural parameters of Portland cement with nanoadditives in the process of hydration are traced. It is shown that the use of nanoadditives makes it possible to control the process of formation of the structure of hydrated Portland cement on the nanoscale level, to directly influence the values of structural parameters and, ultimately, to the properties of cement stone.