The influence of vibro-activated lime additive on the hydration processes of Portland cement and the nature of changes in the strength of cement stone at different stages of its hardening were studied. It was established that long-term storage of vibro-activated lime in a wet state does not weaken its properties as a modifying additive.
This article describes the classification of cationic bitumen emulsions according to "reactivity" and breaking behaviour characteristics. The methods of researching the characteristics of breaking behaviour for bitumen emulsions of different "reactivity" in accordance with European and Ukrainian regulatory documents are presented. Available possible emulsifiers in Ukraine for over-stabilised bitumen emulsions are given with a description of road technology where they can be applied.
The article presents the peculiarities of obtaining superplasticized cementitious systems "Portland cement – fly ash - superplasticizer" to find a rational provision of the given construction and technical properties of concrete. It was studied the physico-chemical peculiarities of the hydration processes of superplasticized cementitious systems. There were solved problems of directional formation of the microstructure of cement stone.
The article considers the possibility of using wastepaper sludge ash (WSA) as a soil reinforcement material for the construction of layers of road wear. Loamy sand, sandy loam, silty clay loam, silty clay were chosen as soils for strengthening. The maximum density of the soil skeleton at optimum humidity was established by the method of Proctor. Wastepaper sludge ash and Portland cement grade 400 were used separately for soil strengthening.
Regulation of hydration processes on nanostructure scale due to the competition adsorption modifying of hydration products by polycarboxylate and adding of nanosized C-S-H nuclei allows promoting homogeneous distribution of solid phase in the structure of cement paste on the micro- and nanolevel, provides the growth of contact amount between hydrates, results rapid structure formation and strength synthesis of Portland cement system.
Production of Portland cement is one of the most energy intensive among building materials, it is accompanied by significant CO2 emissions: 0,7 to 1 ton per 1 ton of cement, depending on manufacturing technology. Therefore, replacement of Portland cement clinker with active mineral additives of natural or synthetic origin is environmentally and economically viable, while not causing significant adverse changes in the properties of cement binders.
The influence of technological factors on the properties of fibre cement articles is investigated. The research reveals an interconnection between microstructure and strength of the cement matrix with the average density, moisture deformation and warping of fibre cement sheets.
Portland cement-based mortars, of the standard type used for modern constructions, were modified by adding lyophilized cactus gum, extracted from an indigenous Mexican cactus. The results show an increase in compressive strength as high as 65 % with respect to standard mortars
The investigation results of changes in cement grout observed during the induction and post-induction periods of hardening while adding fine-grinded glass additives are presented. It is assumed that glass introduction decreases pH of the system due to the chemical interaction with alkaline medium of the cement grout. The obtained results are important for the solving of the problem of glass wastes usage in the cement technology.
The work deals with the modification of mortars by small quantities of nanodispersed material. The effect of amorphous nanosilica on Portland cement hydration and hardening has been investigated. The amorphous nanosilica is compared with the known mineral additive – microsilica.