Underwater non-dispersed concrete is a concrete technology of underwater concrete construction in the world.
Since 1974, SIBO developed an admixture in underwater water
It has been widely used in offshore oil platforms, submarine pipelines,artificial islands, ports, piers, docksDAMS, hydropower stations, Bridges and other projects.
The typical project of minashi Bridge makes Japan more reliable in the reliability of underwater non-dispersed concrete.In recent years。
this method has created many high-quality underwater projects, and realized the “land” of underwater construction
so that the unimaginable new structure.
new design and new construction in hydropower projects can be realized. Hydroxypropyl methyl cellulose (HPMC) has excellent thickening and can be used as an excellent concrete anti-dispersant.
In the past, this material is a domestic fine chemical product in shortage, high cost,
due to various reasons limited its application in China’s construction industry.
In recent years, with the continuous development of external wall insulation technology,
the continuous progress of cellulose production technology, and the excellent characteristics of HPMC itself.
HPMC has been widely used in the construction industry. Condensation time test Concrete condensation time is mainly related to the condensation time of cement, the influence of aggregate is not big,
so you can use mortar condensation time instead of study HPMC on underwater concrete mix condensation time
because mortar condensation time by water cement ratio, cement sand ratio, so in order to evaluate the influence of HPMC on mortar condensation time, need to fix mortar water cement ratio and cement ratio.
It can be seen from the experiment that the addition of HPMC has obvious retarding effect on the mortar mixture, and the condensation time of the mortar is extended with the increase of HPMC mixing amount.
With the same HPMC mixing amount, the mortar formed under water is longer than the condensation time formed in air.
When measured in water, the condensation time of HPMC-mixed mortar was 6 to 18 h and 6 to 22 h compared with the blank specimen.
Therefore, HPMC should be used together with early agents.
HPMC is a polymer polymer, a macromolecular linear structure with hydroxyl group
can form oxygen bonds with mixing water molecules,increasing mixing water viscosity.
The long molecular chains of HPMC will attract each other
making the HPMC molecules entangled with each other to form a network structure, wrapping up the cement and mixed water.
Because HPMC forms a film-like mesh structure and the wrapping effect on cement
it will effectively prevent the volatilization of water in mortar, hinder or slow down the hydration speed of cement.