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 a concrete admixture that makes concrete mixtures easier to pump through a line. It acts as a pump primer and lubricant for the mix and ultimately reduces the pumping pressure necessary to place concrete without altering the sand, cement, water, and aggregate content. Effective pumping aids can also minimize the wear and tear on pumping equipment, thereby extending their lifespan and reducing maintenance costs. By selecting a high-quality pumping aid, construction professionals can achieve a uniform distribution of cementitious materials and improve the overall efficiency and quality of concrete placement.
POLYOX™ WSR 301 is a high–molecular weight polyethylene oxide polymer. It is water-soluble and improves concrete pumpability by thickening the water in the mix, reducing friction within the mix and pipes and providing shear-thinning rheology. The shear-thinning properties of POLYOX™ WSR 301 ensure that the mixture flows smoothly through pipes under high-pressure pumping, which can significantly lower operational stress on concrete pumps. Additionally, by reducing friction, this polymer not only enhances pump efficiency but also mitigates the risk of blockages and other pumping-related issues, contributing to more reliable and cost-effective concrete placement. To test the performance of POLYOX™ WSR 301, two typical concrete mixes were compared side by side.
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, it stabilized air content, allowing for a 20%–30% reduction of air-entraining agents without any detriment to the workability of the concrete.
Benefits of POLYOX™ WSR-301 in Concrete
Improves water retention and distribution with highly porous and harsh aggregate
Pumps longer distances at lower pressures
Prevents aggregate segregation
Stabilizes sprayed concrete
Stabilizes foam in concrete
Summary
Concrete made with small concentrations of the POLYOX™ WSR 301 pumping aid is easier to pump, reduces wear and tear on pumps and pipes, and has better workability at most temperatures. POLYOX™ WSR 301 effectively achieves this through its thickening and lubricating properties, which reduce the energy required for concrete pumps to operate. It also eliminates 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.