PCE powder is a new type of environmentally friendly, green and pollution-free high water reducing admixture for concrete. It has the advantages of low cost, fewer production defects and good performance of water reducing and slump retention.
Typical PCE structure is methoxy-terminated PEG (Plank et al., 2008), but hydroxyl-terminated PCEs can be prepared by radical copolymerization of o-hydroxy PEG methacrylate macromonomers with acrylic acid. These hydroxyl-terminated PCEs have the same structure as methoxy-terminated PCEs but possess different properties, such as higher mechanical strength and better dispersibility.
The particle size distributions of raw material and hydrated samples with or without PCE were measured by laser diffraction technique. The results showed that the average particles in the range of 0.5-2 mm were almost identical, while the distributions of larger particles in the size range of 6-20 mm were significantly changed. The two samples with the highest content of PCE, namely, PCE_0% and PCE_4.8%, were mainly distributed in the range of 6- 20 mm.
The thixotropic index Ithix, a measurement of deflocculation, decreased with the addition of PCE or NSF until their bottom low values. This is due to the adsorption of the surfactant on the surface of the paste particles/agglomerates, which induces electrostatic pressure or steric hindrance, thus dispersing and decreasing the colloidal bonding between the paste particles/agglomerates.
As shown in Figure 2, the hydration heat of CaO in water containing PCE was very fast, with maximum hydration occurring within the first few minutes of water contact. This was accompanied by a dormant period that was proportional to the PCE content.
Ask a quote for the latest price and one of our team members will respond as soon as possible. Fields marked with * are required.
