Water reducing agent on the influence mechanism of apparent viscosity of fresh concrete
As water reducer for concrete research, production and use of rapid development on the workability of concrete water reducing agent mechanism has aroused people's attention. Study on high performance water-reducer think water reducer on the influence mechanism of apparent viscosity of fresh concrete, to discuss water-reducing agent of different mineral compositions and mixed with the adaptability of concrete with different mix materials, so as to give full play to role of water reducing agent.
Water reducing agent on the influence mechanism of apparent viscosity of fresh concrete is divided into the following:
Adsorption and dispersion
Reducing agent is a surfactant
Surfactant in water solution in the molecular can occurred Association collection and generated rubber mission, this is by molecular of structure features decided of, it of molecular General always by non-polar of Pro-oil of carbon hydrogen bonds part and polar of Pro-water group composition of, formed not symmetric of structure, makes this molecular has part can dissolved Yu water, and another part is easy from water in the escape out of double nature. Therefore, they will be relative to the water in the aqueous medium in a unique orientation, a certain structure, and solution of adsorption and solutions within the micelle formation, the two important characteristics.
Cement after mixing with water, its surface wetting by water, and wet conditions on the properties of fresh concrete is very large. Due to the wet, makes the surface of cement particles free energy, cement particles effectively dispersed, to reduce the apparent viscosity of fresh concrete.
Directional adsorbed superplasticizer, polar water molecules hydrogen bond forms combined with hydrophilic groups to enter into, this hydrogen bond is far greater than the force of the molecules and molecular attraction between cement particles (van der Waals force). Dang cement particles surface adsorption enough of reduction agent Hou, with Yu R-SO-3 and water molecular in the hydrogen bonds of Association collection role, again plus water molecular between of hydrogen bonds Association collection, makes cement particles surface formed a layer stable of solvent water film, this layer "space wall barrier" block has cement particles between of directly contact, and in particles between up lubrication role, makes cement particles more dispersed, thus reduced has table views stick degrees.