SkyWay string rails – next phase of testing concrete mixes

SkyWay string rails – next phase of testing concrete mixes

06 Junе 2016 5446

The SkyWay project audience have got to know recently about the specifics of steel used in the construction of the SkyWay routes. Today we present to your attention a photo report from the laboratory of the Belarusian National Technological University, where successful testing for viscosity of concrete mixes has passed. This time they were testing viscosity features of concrete, which are crucial when pumping it through string rails between anchor supports. Production engineer of the design Bureau for reinforced concrete structures, Head of physico-chemical test laboratory at SkyWay Technologies Co. Victor Dolgiy told about the purpose and tasks that SkyWay specialists wanted to achieve during the experiment.

"For concrete mixes, which move through the tubes, the viscosity index is rather more important than their features of slump or standard cone spread, because it is the viscosity that will display the dynamic shift of a viscoplastic fluid in a limited volume.

Concrete mix is a non-Newtonian fluid, i.e. its viscosity depends on the flow rate. Its viscosity decreases with the increase in flow rate of a mix. The performed research on the rotary viscosimeter at the Belarusian National Technological University confirms this. When increasing the flow rate of our mix by 5 times, its viscosity decreases by about 2 times. It means we have determined that at the mix flow rate of 0.2 m/min., its viscosity will be 48 poises, and at the flow rate of 1m/min. – 24 poises. However, the flow rate of the mix in our case while filling will be approximately 0.5 m/sec., i.e. 30 times faster than in laboratory tests on the viscometer. It is now necessary to determine the actual viscosity at this flow rate of the mix and use one of the existing algorithms for the hydraulic calculation of viscous fluids. Our concrete mix can be considered a homogeneous mass, because it does not unscramble and has the maximum aggregate size of 0.6 mm.

Thus, simulating the movement of the concrete mix through tubes, it is possible to predict the range of its pumping, period of filling our rail track and the necessary equipment."

Let us recall that the SkyWay string rail is filled with concrete to increase the strength and stability of the track structure, reduce the level of noise pollution when a SkyWay vehicle is running, as well as the solution to problems of metal corrosion. To date, verification of concrete mix-fillers for SkyWay string rails for compliance with their requirements is at the final stage. The entire set of tests is carried out in accordance with the approved schedule, so that by the time of filling the mixes inside the string rails their functional and technological adequacy would receive a comprehensive and complete confirmation.

Evgeny Petrov