Local supply of modifying components to the vibration compaction zone of a concrete mixture

Abstract

The article considers a system for the local supply of cement slurry or liquid modifying components directly into the compaction zone of a concrete mixture. The feasibility of combining deep vibration action with dosed hydraulic introduction of an active liquid phase is substantiated, which makes it possible to improve the formation of a dense and homogeneous concrete structure. A structural and technological scheme of the system is proposed, which includes a tank for preparing cement slurry or modifying liquid, an electric mixer, a pump, a pressure gauge, a safety valve, a throttle valve, a shut-off valve, a pressure line, and an internal vibrator with a nozzle for local liquid injection. The sequence of system operation is considered, which involves preparing a homogeneous suspension, supplying it under pressure to the internal vibrator, and injecting it through nozzles directly into the active compaction zone of the concrete mixture. It is shown that the local introduction of cement slurry or modifying components into the vibration-activated mixture improves aggregate wetting, reduces voids and dry inclusions, improves the contact between cement stone and aggregate, and increases the homogeneity of the concrete structure. It is established that the system efficiency depends on the coordination of pressure, flow rate, nozzle diameter, supply duration, and vibration compaction mode. The obtained results can be used to improve concrete mixture compaction technology, especially for products of complex shape, densely reinforced structures, stiff and low-workability mixtures, as well as for further substantiation of the parameters of local injection systems for liquid modifying components.