阅读说明：本技术 一种改性复合混凝土早强剂 (Modified composite concrete early strength agent ) 是由 刘少林 刘俊杰 田帅 廖文文 凌志 邓凯 于 2020-08-13 设计创作，主要内容包括：本发明公开了一种改性复合混凝土早强剂,涉及早强剂技术领域,所述早强剂按重量份包括以下组分：三乙醇胺20～30份、微硅粉10～20份、改性膨润土5～15份、改性聚丙烯腈纤维2～6份、水溶性硅酸盐0.5～1.5份、水溶性钙盐0.3～0.8份、氢氧化钠0.1～1份和减水剂0.1～0.3份。本发明添加的改性膨润土具有一定的反应活性,能够提高混凝土的粘结性；通过添加的改性聚丙烯腈纤维能够提高混凝土的韧性及断裂性；且本发明通过不同原料的协同作用以及合理配置,能够有效改善混凝土的性能,提高施工效率,节约生产成本,本发明具有坍落度低、抗压强度高、泌水率低的优点。(The invention discloses a modified composite concrete early strength agent, which relates to the technical field of early strength agents and comprises the following components in parts by weight: 20-30 parts of triethanolamine, 10-20 parts of silica fume, 5-15 parts of modified bentonite, 2-6 parts of modified polyacrylonitrile fiber, 0.5-1.5 parts of water-soluble silicate, 0.3-0.8 part of water-soluble calcium salt, 0.1-1 part of sodium hydroxide and 0.1-0.3 part of water reducing agent. The added modified bentonite has certain reaction activity, and can improve the cohesiveness of concrete; the toughness and the fracture property of the concrete can be improved by adding the modified polyacrylonitrile fiber; the invention can effectively improve the performance of concrete, improve the construction efficiency and save the production cost by the synergistic action and the reasonable configuration of different raw materials, and has the advantages of low slump, high compressive strength and low bleeding rate.)

1. The modified composite concrete early strength agent is characterized in that: the early strength agent comprises the following components in parts by weight: 20-30 parts of triethanolamine, 10-20 parts of silica fume, 5-15 parts of modified bentonite, 2-6 parts of modified polyacrylonitrile fiber, 0.5-1.5 parts of water-soluble silicate, 0.3-0.8 part of water-soluble calcium salt, 0.1-1 part of sodium hydroxide and 0.1-0.3 part of water reducing agent.

2. The modified composite concrete early strength agent according to claim 1, characterized in that: the early strength agent comprises the following components in parts by weight: 25 parts of triethanolamine, 15 parts of silica fume, 10 parts of modified bentonite, 4 parts of modified polyacrylonitrile fiber, 1 part of water-soluble silicate, 0.55 part of water-soluble calcium salt, 0.5 part of sodium hydroxide and 0.2 part of water reducing agent.

3. The modified composite concrete early strength agent according to claim 1, characterized in that: the modified bentonite is prepared by the following method:

s11: firstly, crushing bentonite, and then heating and activating for 2-3 hours to obtain activated bentonite;

s12: adding toluene isocyanate into the activated bentonite, and uniformly stirring to obtain a mixture;

s13: and adding anhydrous toluene into the mixture, stirring and dispersing, filtering and drying to obtain the modified bentonite.

4. The modified composite concrete early strength agent according to claim 3, characterized in that: the adding amount of the toluene isocyanate in the step S12 is 10-15% of the weight of the bentonite; and in the step S13, the addition amount of the anhydrous toluene is 3-5 times of the weight of the bentonite.

5. The modified composite concrete early strength agent according to claim 1, characterized in that: the modified polyacrylonitrile fiber is prepared by the following method:

s21: continuously passing polyacrylonitrile fibers through a heat treatment furnace under the protection of nitrogen, and naturally cooling;

s22: and carrying out surface modification on the polyacrylonitrile fiber subjected to heat treatment by using a silane coupling agent to obtain the modified polypropylene fiber.

6. The modified composite concrete early strength agent according to claim 5, characterized in that: in the step S21, the heat treatment temperature is 180-200 ℃, and the heat treatment time is 1-5 min.

7. The modified composite concrete early strength agent according to claim 1, characterized in that: the water-soluble silicate is any one of sodium silicate, sodium metasilicate or sodium fluosilicate.

8. The modified composite concrete early strength agent according to claim 1, characterized in that: the water-soluble calcium salt is any one of calcium nitrate, calcium formate or calcium acetate.

9. The modified composite concrete early strength agent according to claim 1, characterized in that: the water reducing agent is any one of a polycarboxylic acid water reducing agent or a benzene water reducing agent.

Technical Field

The invention relates to the technical field of early strength agents, in particular to a modified composite concrete early strength agent.

Background

The early strength agent is one of concrete admixtures, and refers to an admixture which can improve the early strength of concrete and has no obvious influence on the later strength. The early strength agent has the main functions of accelerating the hydration speed of the cement and promoting the development of the early strength of the concrete; not only has the early strength function, but also has certain water reducing and enhancing functions. The concrete early strength agent is one of the earliest used additive varieties in the development history of the additive.

However, the concrete early strength agent in the current market has high concrete slump in the actual use process, can improve the early compressive strength of the concrete, but cannot improve the later compressive strength of the concrete, has low overall compressive strength, has high bleeding rate and high production cost, and cannot meet the requirements of the current market. Therefore, the modified composite concrete early strength agent is provided by the technical personnel in the field to solve the problems in the background technology.

Disclosure of Invention

The invention aims to provide a modified composite concrete early strength agent, which can effectively improve the performance of concrete, improve the construction efficiency and save the production cost through the synergistic effect and reasonable configuration of different raw materials.

In order to achieve the purpose, the invention provides the following technical scheme: the modified composite concrete early strength agent comprises the following components in parts by weight: 20-30 parts of triethanolamine, 10-20 parts of silica fume, 5-15 parts of modified bentonite, 2-6 parts of modified polyacrylonitrile fiber, 0.5-1.5 parts of water-soluble silicate, 0.3-0.8 part of water-soluble calcium salt, 0.1-1 part of sodium hydroxide and 0.1-0.3 part of water reducing agent.

As a further scheme of the invention: the early strength agent comprises the following components in parts by weight: 25 parts of triethanolamine, 15 parts of silica fume, 10 parts of modified bentonite, 4 parts of modified polyacrylonitrile fiber, 1 part of water-soluble silicate, 0.55 part of water-soluble calcium salt, 0.5 part of sodium hydroxide and 0.2 part of water reducing agent.

As a still further scheme of the invention: the modified bentonite is prepared by the following method:

s11: firstly, crushing bentonite, and then heating and activating for 2-3 hours to obtain activated bentonite;

s12: adding toluene isocyanate into the activated bentonite, and uniformly stirring to obtain a mixture;

s13: and adding anhydrous toluene into the mixture, stirring and dispersing, filtering and drying to obtain the modified bentonite.

As a still further scheme of the invention: the adding amount of the toluene isocyanate in the step S12 is 10-15% of the weight of the bentonite; and in the step S13, the addition amount of the anhydrous toluene is 3-5 times of the weight of the bentonite.

As a still further scheme of the invention: the modified polyacrylonitrile fiber is prepared by the following method:

s21: continuously passing polyacrylonitrile fibers through a heat treatment furnace under the protection of nitrogen, and naturally cooling;

s22: and carrying out surface modification on the polyacrylonitrile fiber subjected to heat treatment by using a silane coupling agent to obtain the modified polypropylene fiber.

As a still further scheme of the invention: in the step S21, the heat treatment temperature is 180-200 ℃, and the heat treatment time is 1-5 min.

As a still further scheme of the invention: the water-soluble silicate is any one of sodium silicate, sodium metasilicate or sodium fluosilicate.

As a still further scheme of the invention: the water-soluble calcium salt is any one of calcium nitrate, calcium formate or calcium acetate.

As a still further scheme of the invention: the water reducing agent is any one of a polycarboxylic acid water reducing agent or a benzene water reducing agent.

Compared with the prior art, the invention has the beneficial effects that: the invention discloses a modified composite concrete early strength agent, the modified bentonite added in the invention has certain reaction activity, and can improve the cohesiveness of concrete; the toughness and the fracture property of the concrete can be improved by adding the modified polyacrylonitrile fiber; the invention can effectively improve the performance of concrete, improve the construction efficiency and save the production cost by the synergistic action and the reasonable configuration of different raw materials, and has the advantages of low slump, high compressive strength and low bleeding rate.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the embodiment of the present invention, the first and second substrates,