Method for controlling setting time and early hydration speed of magnesium potassium phosphate cement

Abstract

The invention relates to a method for controlling the setting time and early hydration speed of magnesium potassium phosphate cement, and belongs to an early strength quick hardening cement cementing material. A composite retarder can effectively adjust the setting time of magnesium potassium phosphate cement slurry, and the setting time of the magnesium potassium phosphate cement slurry can be effectively controlled in the range of 10 minutes to 6 hours by adjusting the content of chloride and disodium hydrogen phosphate dodecahydrate in the composite retarder, so that the problems of a limited retarding effect, low operability and the like are solved; the composite retarder can change the hydration heat release characteristic of the magnesium potassium phosphate cement, the magnesium potassium phosphate cement slurry doped with the conventional retarder borax has a hydration heat release peak at the initial reaction stage and has a high heat release speed and large heat release amount, and the magnesium potassium phosphate cement doped with the composite retarder has two hydration heat release peaks and has small hydration heat release amount at the initial hydration stage; and the doped composite retarder improves the microstructure and later strength of a hardened magnesium potassium phosphate cement body, so that enough construction operable time can be ensured while the magnesium potassium phosphate cement slurry has early strength and is quickly hardened.

Description

technical field [0001] The invention relates to an early-strength and quick-hardening cement cementitious material, in particular to a method for controlling the setting time and early hydration speed of magnesium potassium phosphate cement. Background technique [0002] After searching the domestic and foreign cement technology overview: some developed countries in the West have used magnesium phosphate cement in large quantities since the 1990s in the rapid repair of concrete pavements and industrial plants, curing harmful and radioactive waste, and producing building materials in combination with industrial waste. The investigation of the use of magnesium phosphate cement to repair the road surface has proved its durability effectively. In my country: some scholars and enterprise scientific and technological research and development personnel have conducted various researches on the mechanical properties of magnesium phosphate cement and various properties as repair mater...

AI Technical Summary

Problems solved by technology

MgO with low activity requires a higher calcination temperature and is difficult to control. Too coarse MgO will affect the fluidity and early strength of the magnesium phosphate cement hardened body, and the retarding effect is not obvious when the ambient temperature is high

[0005] (3) The main components of magnesium phosphate cement are dead-burned magnesia and phosphate. Increasing the content of phosphate can appropriately delay the setting time of magnesium phosphate cement, but when more phosphate is added, it will increase the cost of magnesium phosphate cement and reduce the cost. The strength and water resistance of magnesium phosphate cement, and the retarding effect is not good when the ambient temperature is high

Foreign countries have designed two formulas for traditional magnesium phosphate cement in winter and summer. There have been reports that low-temperature cooling water is used to mix magnesium phosphate cement slurry to delay the setting time of slurry in high-temperature environment in summer, but the practical operability is poor.

[0007] In foreign countries, there are relevant reports on the method of delaying the setting time of magnesium phosphate cement slurry, but there are certain limitations and side effects. It can only be delayed for a few minutes, and the operability is poor.

In China, scientific and technical personnel of scientific research institutions and cement enterprises are constantly researching and exploring the preparation technology of magnesium phosphate cement. Although some achievements have been made, there are still technical problems that have not been overcome in practical application.

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