Methyl hydroxyethyl cellulose (MHEC) is a kind of methyl cellulose derivative which is made from natural high polymer cellulose. It is widely used in many different industries as water retention agent, thickener, adhesive agent and dispersant etc. It could dissolve in water and form a clear solution with specific viscosity. MHEC has a good stability even though in alkaline environment and provide a good stability in heat environment. Widely used in drymix mortar industry, oil drilling, detergent and paint ＆ costings etc.

Generally, three principle working mechanisms for water retention can come into place whenever a cement paste is subject to filtration on a substrate. These potential mechanisms have been proposed in earlier works by Desbrières and are as follows [20], [21]: (a) Water retention as a result of increased viscosity: increased dynamic filtrate viscosity can decelerate the filtration rate. (b) Water retention as a result of adsorption: anionic polymers may adsorb onto hydrating cement particles and obstruct filter cake pores either by polymer segments which freely protrude into the pore space or even bridge cement particles. Through this mechanism, filter cake permeability is reduced. (c) Water retention as a result of physical pore plugging: polymers may plug pores in the cementitious matrix through formation of polymer films (e.g. latexes), or through large polymer associates which form a 3D network, or through simple swelling and expansion caused by the uptake of an enormous amount of water into the inner sphere and hydrate shells of polymers. This process leads to the formation of large microgel particles. Through this mechanism, a large portion of the mixing water is physically bound and cannot leak-off into a porous substrate. The enormous water-binding capacity of polysaccharides has been described in an earlier study. By using a sorption balance and a microcalorimeter it was found that at the saturation level, neutral polysaccharides (amylose and amylopectin) can bind up to four water molecules per anhydroglucose unit [22].