Technology of casting precast pipeline elements of the Kaisiadorys pumped-storage station

Conclusions

• 1. The use of the cast concrete mix with a superplasticizer for concreting structures is technically expedient and economically effective.

• 2. Such structures are: bored piles, heavily reinforced structures, plain cast, those cast in reinforcement panels, precast pipelines, etc.

  More thorough investigations into the problems of the rate of delivering the mix and schemes of concreting for the purpose of reducing the pressure of the mix on the formwork are required for using the cast concrete mix in thin-walled structures, for example, in retaining walls.

  When concreting high structures it is advisable to add to the concrete mix just the superplasticizer without set retarders, which provides a shorter period of the keeping qualities of the superplasticizer in the concrete (Fig. 1) and approximates the concreting scheme to the scheme of layer-by-layer placement of an ordinary mix with average fluidity. This will make it possible to dispense with the bracing of the formwork calculated for the lift but not the total pressure of the concrete mix over the entire height of the structure when concreting by the usual scheme.

• 3. The authors consider that the superplasticizer should, as a rule, be used on all large construction projects of Minénergo, taking into account the presence of its own production in this sector.

• 4. Superplasticizers should be used when it is necessary to increase the concrete strength (by reducing the W/C ratio) and fluidity of the concrete mix, for example, when transporting the mix by truck mixers and concreting structures by concrete pumps. In this case the addition of the plasticizer requires a correction of the mix to provide its homogeneity and absence of bleeding, which reduces to a change in the content of aggregates in the composition.