cement

Pavement grade cationic bitumen emulsions formulations were developed for Slurry Surfacing based on orthophosphoric and hydrochloric acids with both all-purpose and specialized emulsifiers used. As a result, there were established relations of mix time upon cement - for Slurry Surfacing based on various acids and emulsifiers. Mix time of Slurry Surfacing mix (having different cement content) with bitumen emulsions on both orthophosphoric and hydrochloric acids is characterized by parabolic relation, branches of the parabola going down.

Studies of moisture loss from hardening monolithic cement concrete have been carried out. It was found that there is no consensus on the critical value of moisture loss from hardening concrete, at which shrinkage and cracking are possible, and there is no common understanding of the possible critical width of the shrinkage crack opening. It is shown that when the concrete hardens in air-dry conditions, its indicators, including durability, decrease by a factor of 2 or more. The critical value of moisture loss from hardening concrete was experimentally determined, which is 2 kg/m2.

The paper presents research of brittleness cement blends with siliceous additives using impact strength. The advantages of the developed method are simplicity of definition, low cost of equipment and operation. In the presented research were studied additives on the basis of finely ground glass obtained from waste glass containers and pozzolanic additives as fly ash, silica fume and synthetic silica. Increase in additives amount in respect to the cement mass reduces brittleness by ~10 % after 28 days of curing.

The new method determination parameters hardening of portland cement is offered in the article.

The glass wastes as a cullet are widely used for the production of building materials mainly as inert aggregate. However finely grained glass powder has the very developed surface, so can not be passive toward cement solutions, what was confirmed in practice. In literature data there is no information about chemical influence of finely grained glass on the process of hardening, especially in an early pre-induction hydration period, which substantially causes the structure formation of cement stone and its properties.

In the work the results of research the physico-mechanical properties of cements with the use of barium-containing sulfateferrite clinkers and gypsum stone are given. As a result of research of barium-containing sulfateferrite clinkers hydraulic properties it is found out that while concretion they show too fast hardening and low solidity therefore they cannot be used as an independent binder. For the purpose of regulation the hardening terms the influence of the gypsum stone additive was studied.

The usage of fine grinded silicate glass as an active additive to Portland cement has been considered in order to substitute neat cement in the cement composition, just as it is in EN 197-1 European standard by the example of active mineral additives of natural and artificial origin.