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    Pumpable Concrete

    Ordinarily, concrete mixtures are not ideal for pumping. The pressure used to pump these mixtures often forces water out of the cement, leaving some portions dry and others wet. The friction caused by fine particles in the mixture is also a concern; concrete pumps must operate at higher pressures to offset this friction.

     

Modifying the mix by adding more sand, cement, or water to achieve better pumping performance often leads to undesirable physical properties and increased costs. Admixtures called pumping aids are commonly used to improve the pumpability of concrete and reduce the overall cost of placement.

What Is a Pumping Aid?

Simply put, a pumping aid is an admixture that makes concrete mixtures easier to pump through a line. It acts as a lubricant for the mix and ultimately reduces the pumping pressure necessary to place concrete without altering the sand, cement, water, and aggregate content. 

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POLYOX™ WSR 301 is a high–molecular weight polyethylene oxide polymer that improves concrete pumpability by thickening the water in the mix, reducing friction, and providing pseudoplastic (shear-thinning) rheology. To test the performance of POLYOX™ WSR 301, two typical concrete mixes were compared side by side.
 

    Component
    Formulation A
    Formulation B
    Cement (kg)
    307
    307
    POLYOX™ WSR-301 (g)
    60
    0
    Sand (kg)
    863
    863
    Aggregate and Water (kg)
    1259
    1259

POLYOX™ WSR 301 was included in Formulation A at 25 ppm and reduced the pumping pressure of the mix by 16% without impacting the compressive strength or causing shrinkage upon drying. In addition, POLYOX™ WSR 301 stabilized air content, allowing for a 20%–30% reduction of air-entraining agents without any detriment to the workability of the concrete. POLYOX™ WSR 301 also has film formation properties that efficiently encapsulate mineral powders and aggregates.

Benefits of POLYOX™ WSR-301 in Concrete

 

  • Improved water retention and distribution with highly porous, harsh aggregate
  • Concrete pumps are more efficient, allowing pumping over longer distances using lower pressures
  • Prevents aggregate segregation
  • Stabilizes sprayed concrete
  • Waterproofs underwater concrete to improve setting qualities
  • Stabilizes foam in concrete

Summary

Concrete made with small concentrations of POLYOX™ WSR 301 pumping aids is easier to pump, shows reduced rebound, and is easily workable at most temperatures. POLYOX™ WSR 301 effectively achieves this through its thickening and lubricating properties. These properties reduce the energy required for concrete pumps to operate and eliminate the need to change the cement, water, or aggregate composition of concrete mixes to achieve optimal pumping performance. Click below to request a sample of POLYOX™ for your concrete mix.

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