University of Architecture, Civil Engineering and Geodesy

About: University of Architecture, Civil Engineering and Geodesy is a education organization based out in Sofia, Bulgaria. It is known for research contribution in the topics: Finite element method & Beam (structure). The organization has 3808 authors who have published 3822 publications receiving 30736 citations. The organization is also known as: Sofia Polytechnic.

Processes of structure formation and paste matrix hydration with multilayer carbon nanotubes additives

Abstract: The creation of high-strength materials with targeted structure formation and hydration to obtain building composites with a given set of properties represents a relevant area of the modern construction sector. This paper investigates promising nanomodifying additives i.e. multilayer carbon nanotubes along with an effective method to obtain a comprehensive nanomodifying additive through pre-ultrasonic dispersion of MWCNT globules of varying dispersive capacity in an isopropyl alcohol medium. The comprehensive nanomodifying additive obtained is characterized by high stability as well as a uniform distribution of carbon nanotubes in the additive. The Structure software package developed by the authors was used to study the structure of paste matrix at the mesastructural level. The modification of paste matrix by means of the developed comprehensive nanostructure additive reduces the crack length index to 113% with the crack length ratio and the crack shape ratio going down to 61% and 34%, respectively. The increase in the strength and durability of the compositions modified by the developed comprehensive nanomodifying additive is due to a more complete filling of the intergranular void with newly formed structures in the form of C-S-H (I), tobermorite and gel phases which enhance the degree of packing and density of the composite under examination. However, the share of nano - and micropores goes up by 1.21 and 1.31 times, respectively, while the share of meso - and macropores decreases by 1.51 and 5.25 times.

Modification of Road Soil Cement with Activated Fillers

Abstract: The efficiency of obtaining mineral active fillers for modifying cement-based pavements by various grinding devices was comparatively assessed. A comprehensive comparative assessment of grinding devices (ball, spring mills, disintegrator, and vortex machine) was performed according to the quality indicators of the obtained powders and the results of their modification of road soil cements. The parameters of powders (specific surface area and particle size distribution) were determined. A disintegrator and a vortex machine were chosen as the most appropriate grinding devices for obtaining activated powders. Strength indicators of soil cement for road purposes, modified with activated mineral fillers, were determined. It can be useful for identifying a number of theoretical concepts on the problem of modification by activated fillers in building materials science.