Nanotechnologies in Construction: A Scientific Internet-Journal

536-544

Authors: Katarzyna S., Rucińska T.

This study presents the experimental results on the effects of curing temperature and nanosilica, on the compressive strength and absorbing properties of cement mortars. Two groups of mortars were prepared, with the first containing reference samples. The second group was modified with a nanosilica admixture by 3% of the weight of cement. The mortar specimens were cured in 20оC, 10оC and 5оC constant temperature environments. Compressive strength after 12 h, 1, 2, 7 and 28 days, water absorption and capillary porosity were evaluated on a 40×40×40 mm prism. The results confirmed that a low curing temperature delays strength development in the early days of hydration and slows down the strength growth rate of mortars, with an increase in age. The incorporation of nanosilica has a positive effect in improving the mechanical properties of cement mortars cured at low temperatures. Additionally, nanosilica contributes to decreasing the porosity of the cement matrix, so that transport properties, such as open porosity and sorptivity, improve under all curing conditions.

565-576

Authors: Vakhitova R.I., Saracheva D.A., Mazankina D.V., Kiyamov I.K., Sabitov L.S.

The use of nanotechnology in the construction industry improves its efficiency. The application of nano-modified materials makes it possible to reduce capital costs. Currently the introduction of nanomaterials is of great importance for the construction industry. Carbonaceous structures can be used as nano-modifiers. Carbon nanotubular material TUBALL produced by OCSiAl.ru LLC has been chosen. To perform research samples of single-layer and multi-walled carbon nanotubes were used as a part of cement heavy concrete. The optimal dosage of carbon nanotubes in the composition of cement concrete has been experimentally determined. The studies revealed that addition of TUBALL carbon nanotubes to the cement composition contributed to the formation of a mesh structure that resists the formation of shrinkable nanoscale cracks in the cement mortar, promotes the appearance of calcium hydrosilicates, increases the concentration of calcium ions at the start of the hydration period.