Cement nano-suspension concrete early strength agent and preparation method thereof

Abstract

The invention discloses a cement nano-suspension concrete early strength agent and a preparation method thereof. Nanometer Portland cement, a polycarboxylic acid dispersing agent and polyvinylpyrrolidone (PVP) are utilized to prepare a suspension through a special process. The suspension has a remarkable promoting effect on cement hydration, the early strength of concrete is rapidly improved, thestrength can reach 15 MPa or above after 6-8 h, the formwork removal strength requirement of a prefabricated part is met, the formwork turnover period is shortened, the production cost is reduced, andthe concrete early strength agent is low in cost and excellent in performance.

Description

technical field [0001] The invention relates to a concrete early-strength agent, in particular to a cement nano-suspension concrete early-strength agent and a preparation method thereof. Background technique [0002] With the rapid development of my country's construction industry, especially in recent years, the state and local governments at all levels have promoted the policy of prefabricated buildings, the demand for concrete prefabricated components has increased sharply, and one of the most important indicators for the production of prefabricated components is the early stage of concrete The development of strength can quickly reach the mold removal strength (>15MPa), which is conducive to the rapid turnover of molds, shortens the turnover period of molds, and saves production costs. For this reason, steam curing or pressure steam curing is usually used to quickly achieve the strength of form removal, but the steam curing process consumes energy, destroys the interna...

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Problems solved by technology

For this reason, steam curing or pressure steam curing is usually used to quickly achieve the strength of form removal, but the steam curing process consumes energy, destroys the internal structure of concrete, and affects durability

In order to realize the natural curing process, accelerators are usually added to concrete. Inorganic salt accelerators, such as calcium chloride, calcium nitrate, etc., organic accelerators, such as triethanolamine, but the accelerators are sensitive to the dosage and There are disadvantages such as the reduction of concrete strength in the later stage; increasing the fineness of cement is also a method to improve the early strength of concrete. The greater the fineness, although the early strength is improved, it is not beneficial to the later strength, and the concrete is easy to crack and reduce durability.

[0003] In recent years, many researchers in the industry have found that by adding nanoparticles that can promote cement hydration in cement concrete, the hydration rate of cement can be significantly increased, thereby rapidly improving the early strength of concrete, such as nano calcium silicate hydrate, nano Silica, etc., as the crystal nucleus of cement hydration, the product exists in the form of powder or suspension, but these crystal nucleus early strength agents have high salt content, and the preparation process is relatively complicated and the cost is high

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