Nanoconcrete

Incorporating ultra-fine particles into a Portland-cement paste within a concrete mixture in accordance with top-down approach of nano technology reduces the void space between the cement and aggregate in the cured concrete. This improves strength, durability, shrinkage and bonding to steel reinforcing bars.^[2]

Recent studies have explored the use of computer vision techniques for detecting structural changes in lightweight concrete modified with nanoparticles. These approaches enable non-destructive assessment of microstructural heterogeneity and degradation processes in advanced cement-based materials.^[4]

To ensure the mixing is thorough enough to create nanoconcrete, the mixer must apply a total mixing power to the mixture of 30–600 watts per kilogram of the mix. This mixing must continue long enough to yield a net specific energy expended upon the mix of at least 5000 joules per kilogram of the mix.^[5] and may be increased to 30–80 kJ per kilogram. A superplasticizer is then added to the activated mixture which can later be mixed with aggregates in a conventional concrete mixer. In the HEM process, the intense mixing of cement and water with or without sand in conditions of queasy laminar flow, Reynolds number 20-800 provides dissipation and absorption of energy by the mixture and increases shear stresses on the surface of cement particles. As a result, the temperature of the mixture increases by 20–25 and more degrees Celsius. This intense mixing serves to deepen hydration process inside the cement particles. The nano-sized colloid Calcium Silicate Hydrate (C-S-H) formation increased several times compared with conventional mixing. Thus, the ordinary concrete transforms to nanoconcrete. The initial natural process of cement hydration with formation of colloidal globules about 5 nm in diameter^[6] spreads into the entire volume of cement–water matrix as the energy expended upon the mix.^[7] The liquid activated mixture can be used by itself for casting small architectural details and decorative items, or expanded with gas-forming admixture for making Aerated HEM Nanoconcrete ^[8] as a lightweight concrete. HEM Nanoconcrete hardens in low and subzero temperature conditions because the liquid phase inside the nano-pores of C-S-H gel doesn't freeze at temperatures from −8 to −42 degrees Celsius.^[9] The increased volume of gel reduces capillarity in solid and porous materials.