foam concrete

The waste of foundries of machine-building plants - spent moulding mixtures was studied. The expediency of using spent mixtures of foundry production as a siliceous component of foam concrete mixtures has been proven. The spent mixtures were studied for their foaming ability. The foam properties are determined. The effect of concrete mixture components on the pore-forming ability of foam agents was investigated. Of the six foaming agents studied in the work, saponified tree resin was found to be the most effective.

Production of foam concrete products and monolithic concreting from them requires foaming agents that have the properties of the obtained foam with a sufficient value of its criteria (multiplicity of foaming, stability of foam for a certain period of time); its compatibility with Portland cement and its hydration products; with hydrated lime, etc. Insufficient properties of the foam can be compensated by the introduction of corrective and stabilizing additives.

The full market of Ukraine by various foaming agents of domestic and foreign production requires the study of their technical properties and properties of foam on their basis. The article presents the results of research on the multiplicity of foam formation and foam stability during a certain period of time. The comparative characteristic of such properties of foaming agents allows them to be used successfully in the production of foam concrete.

The article is devoted to the method of reinforcement bonding stress calculation in foam concrete, which is based on the new approach described in DSTU B V.2.6-156: 2010, and the author’s proposals, the most important of which is the replacement of the concrete tensile strength value by the compressive strength with conversion factor. The determination of values of safety factor of the material for two boundary conditions also confirmed the accuracy of proposed algorithm.

The article is devoted to the stress-strain behavior, cracking and bearing strength of plain and reinforced non-autoclaved foam concrete slab spunched through rigid stamp. Experimental researches were held on slabs freely supported along the contour. Authors made an effort to determine the level of loading that corresponded the start of cracking and it was set at the level of 0,6 Ncr . There was also evaluated the ultimate tensility of foam concrete.