Pumping of concrete over a long distance, significantly exceeding the available length of the boom, that is: the distance exceeding 100-150 meters requires special preparation of the pumping infrastructure. The basic issue that must be met by technologists designing a concrete mix is the concrete-pumpability itself. The basic parameters of pumpability are the amount of cement, ash content and plasticizers in the mix. During pumping, the concrete can not get into dehydration, because it will obviously cause clogging of the pipeline.
Preparation of the pipeline for concrete pumping.
Pumping of concrete over a long distance requires proper pipeline preparation. The essential thing is the strength of the entire pipeline system, because exceeding the working pressure of concrete above 85 bar excludes the use of standard flange systems on pipeline connections. It is necessary to use high-pressure pipelines in the ZX connection system (according to Putzmeister nomenclature) or ORZ (according to the system used by CIFA). It is necessary to analyze the required wall thickness of the pipeline for specific parameters of the working pressure. It is recommended to use pipelines with a minimum wall thickness of 7.1 mm. Preparation of pipelines for long distance pumping requires pipe anchoring. Movement of the pipeline resulting from the pulsation of the concrete pumping system is highly not recommended and may lead to leaks on pipeline-joints .
Anchoring of the pipeline especially concerns the elements just after the pump outlet. The lack of a stable attachment may damage the pipeline components. Preparation of a pipeline for long distance pumping excludes the use of hoses for concrete pumping in the pipeline line. The hoses are causing additional pumping resistance. Changes in the direction of the pipeline should be made by using elbows with a large radius of R = 500 or R = 1000 and angles of 30, 45 and 90 degrees.
Each high-rise pipeline can be connected to a truck mounted concrete pump to deliver a mixture to the higher floors of the building without changing the place of concrete supply.
In case of long distance pumping while connected to a stationary concrete pump, it is possible to arrange effective pumping of concrete mix at low altitudes and cover a large area by starting from the most distant point and by shortening the pipeline length