CN110577383A

CN110577383A - Super-retarding concrete

Info

Publication number: CN110577383A
Application number: CN201911020891.6A
Authority: CN
Inventors: 梁新宇; 周洪林; 李桂冲
Original assignee: Sichuan Xinmin Green New Building Materials Technology Co Ltd
Current assignee: Sichuan Xinmin Green New Building Materials Technology Co Ltd
Priority date: 2019-10-25
Filing date: 2019-10-25
Publication date: 2019-12-17

Abstract

The invention discloses super-retarding concrete, which relates to the technical field of concrete and comprises the following raw materials in parts by weight: 380 parts of cement, 80-100 parts of mineral powder, 125 parts of fly ash, 1600 parts of natural gravel, 700 parts of yellow sand, 3-8 parts of super retarder and 200 parts of water. The preparation method of the invention has the advantages of improving the initial setting time of the concrete and improving the strength of the concrete.

Description

Super-retarding concrete

Technical Field

the invention relates to the technical field of concrete, in particular to super-retarding concrete.

Background

the concrete is artificial stone which is prepared by taking cement as a main cementing material, adding water, sand, stones and chemical additives and mineral admixtures if necessary, mixing the materials according to a proper proportion, uniformly stirring, densely molding, curing and hardening.

the existing concrete is generally formed by pouring after mixing and stirring aggregate, a cementing material and various auxiliary agents. The initial setting time of concrete during pouring and forming needs to be adjusted according to actual construction conditions, for example, in the case of overlong construction of an occlusive pile, the initial setting time of concrete is generally required to be about 60 hours, while the initial setting time of general concrete is about 6-8 hours, so that the general concrete cannot adapt to the construction condition.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide the super-retarding concrete, and the initial setting time of the concrete is greatly prolonged by adding the super-retarding agent.

The above object of the present invention is achieved by the following technical solutions:

The super-retarding concrete comprises the following raw materials in parts by weight:

by adopting the technical scheme, the natural macadam and the yellow sand are main aggregates of the concrete, the cement is used as a cementing material for filling gaps among the coarse aggregate, the fine aggregate and the fine aggregate, and has a binding effect, and the mineral powder and the fly ash are mainly used as admixtures for improving the strength of the concrete, reducing the hydration heat of the concrete, improving the sulfate resistance of the concrete and the like. The super retarder prepared by compounding is added, so that the water reducing agent has the function of reducing the water consumption in the concrete mixing process, the initial setting time of the concrete is shortened, the hydration heat and the hydration speed of the concrete are reduced, and the initial setting time of the concrete is greatly prolonged so as to adapt to construction conditions such as occlusive piles and the like requiring a long initial setting time condition.

The invention is further configured to: the super retarder comprises the following components in percentage by weight:

By adopting the technical scheme, the super retarder is compounded by adopting the retarding material and the water reducing agent, and the super retarder obtained by compounding has more functions and higher stability than a common retarder. The calcium adipate belongs to molasses retarding water reducers, has strong solid-liquid surface activity, can be adsorbed on the surfaces of unhydrated cement particles to form a shielding film, blocks the hydration process of cement and generates a retarding effect. Sodium fluorosilicate is an inorganic retarder, and can be combined with calcium ions in cement to be solidified in the cement hydration process, and the solidified sediment can be accumulated on the surface of unhydrated cement particles, so that the effect of inhibiting cement hydration is achieved, and the effect of delaying coagulation is achieved. Itaconic acid and sodium gluconate are both derivatives of glucose, and can be adsorbed on calcium hydroxide crystal nuclei generated in the hydration process in the cement hydration process when added, so that the continuous growth of the cement is inhibited, and the delayed coagulation effect is achieved. The emulsifier is mainly used for improving the dispersion effect of the organic retarder, so that the retarder is dispersed in cement more uniformly, and the coagulation effect is better. The sodium lignosulfonate water reducing agent is a typical anionic surfactant, has higher molecular weight and certain air entraining effect, and can improve the fluidity of concrete and reduce the using amount of water. The retarder with different types in the super retarder is compounded, so that a certain synergistic effect can be achieved, and the application range is expanded.

the invention is further configured to: the emulsifier is one or more selected from OP-40 emulsifier, sodium dodecyl sulfate and GR-200 paraffin emulsifier.

The invention is further configured to: 3-5 parts by weight of an enhancer is added into the delayed coagulation concrete, and the enhancer comprises the following components in percentage by weight;

By adopting the technical scheme, the steel fiber mainly improves the toughness and ductility of the concrete after initial cracking, but does not greatly contribute to early temperature cracks or shrinkage cracks of the concrete. The polypropylene fiber has unique apparent characteristics and smaller fiber diameter, can thin cracks of a concrete structure under the action of long-term fatigue load, and provides favorable conditions for natural healing of concrete microcracks. Compared with other synthetic fibers, the polypropylene fibers have more fiber numbers under the same volume mixing amount, so that the polypropylene fibers have better bonding performance with a concrete matrix, and the crack resistance and the ductility of the concrete are improved.

the rolling auxiliary agent changes the surface performance of the steel fiber, so that the polypropylene fiber and the steel fiber can be twisted into the mixed fiber in one step under the action of the rolling auxiliary agent, the toughness and the ductility of the twisted mixed fiber after the initial crack of the concrete are improved after the twisted mixed fiber is added into the concrete, and the initial crack of the concrete can be self-healed faster while the toughness and the ductility of the concrete are improved, so that the initial setting strength of the concrete is improved.

The invention is further configured to: the reinforcing agent also comprises self-repairing microcapsules, and the reinforcing agent comprises the following components in percentage by weight:

By adopting the technical scheme, the self-repairing microcapsules are attached between the polypropylene fibers and the steel fibers when the polypropylene fibers and the steel fibers are rolled, and the self-repairing microcapsules enable the polypropylene fibers to provide a favorable environment for the initial cracks of the concrete, the self-repairing microcapsules in the twisted mixed fibers can enter the cracks, when the self-repaired concrete generates cracks again under pressure, the cracks are expanded to the self-repairing microcapsules, the self-repairing microcapsules are broken, core materials in the microcapsules repair the cracks, and the strength of the concrete is recovered.

In addition, in the hardening stage of the concrete, part of the self-repairing microcapsules can be broken due to the hardening process, so that the core material in the self-repairing microcapsules seeps out in the hardening process, the hardening of the concrete is further strengthened, and the strength of the concrete is improved.

the invention is further configured to: the rolling aid comprises the following components in percentage by weight:

by adopting the technical scheme, the silane coupling agent modifies the surface of the steel fiber, so that the compatibility between the contact surfaces of the polypropylene fiber and the steel fiber is improved when the polypropylene fiber and the steel fiber are twisted. The OP-40 emulsifier has better dispersion and emulsification effects on the silane coupling agent, so that the silane coupling agent is more uniformly dispersed on the surface of the steel fiber. And a proper amount of epoxy resin is added into the rolling auxiliary agent, so that the bonding strength between the polyacrylic fiber and the steel fiber is improved, and the steel fiber and the polypropylene fiber are not easy to disperse. Butyl acetate is used as a solvent for improving the fluidity of the twisting aid, so that the steel fibers and the polypropylene fibers can be coated with the twisting aid more thoroughly.

The invention is further configured to: the core material of the self-repairing microcapsule is an acrylate core material; the wall material is urea-formaldehyde resin.

by adopting the technical scheme, the wall material urea-formaldehyde resin of the self-repairing microcapsule particles has certain strength, when cracks are generated in the concrete and extend to the positions of the self-repairing microcapsule particles, the wall material of the self-repairing microcapsule particles is damaged to release the acrylate core material, and the positions of the generated cracks are repaired by the acrylate core material, so that the durability of the concrete is improved. And acrylic acid generated by decomposing part of acrylic ester can be subjected to copolymerization reaction with itaconic acid in concrete to generate an itaconic acid-acrylic acid copolymer, so that the bonding strength between concrete gaps can be improved, and the copolymer is also a chelating agent which can chelate heavy metal ions in the concrete and can prevent the heavy metal ions from permeating the concrete layer to pollute the environment.

Compared with the prior art, the invention has the beneficial effects that:

1. The super retarder is added into the concrete, so that the initial setting time of the concrete is greatly prolonged, and the concrete can adapt to the working condition with longer initial setting time for construction;

2. By adding the reinforcing agent, the strength of the concrete is improved, and the concrete can be repaired when cracks appear, so that the durability is improved.

Detailed Description

The present invention will be described in detail with reference to examples.

example 1:

the invention discloses super-retarding concrete which comprises the following raw materials in parts by weight:

Wherein the super retarder comprises the following components in percentage by weight:

The emulsifier in the super retarder is OP-40 emulsifier.

According to the weight percentage, the raw materials of the reinforcing agent comprise 30 percent of polypropylene fiber, 30 percent of steel fiber, 5 percent of rolling auxiliary agent, 5 percent of self-repairing microcapsule, 2 percent of dispersing agent and 28 percent of water, wherein the rolling auxiliary agent comprises 30 percent of silane coupling agent, 10 percent of OP-40 emulsifier, 5 percent of epoxy resin and 55 percent of butyl acetate. The core material of the self-repairing microcapsule is an epoxy resin core material; the wall material is urea-formaldehyde resin.

The preparation method of the reinforcing agent comprises the following steps: and rolling the polypropylene fibers and the steel fibers by using an elasticizer, spraying a mixed solution of a rolling auxiliary agent, self-repairing microcapsules, a dispersing agent and water in the rolling process, cutting the obtained rolled fibers, and adding the cut rolled fibers into concrete.

the difference between the examples 2-5 and the example 1 is that the raw materials in the ultra-retarding concrete are as follows in parts by weight.

examples 6-9 differ from example 1 in that the components of the ultra retarder, in weight percent, are as follows.

Examples 10-14 differ from example 1 in that the ingredients in the emulsifier in the ultra retarder are in the following table in weight percent.

The difference between the examples 15 to 18 and the example 1 is that the raw materials in the reinforcing agent are as follows in percentage by weight.

Examples 18 to 17 differ from example 1 in that the components of the kneading aid are in the following table in weight percent.

Comparative example

comparative example 1 differs from example 1 in that no super retarder was added to the concrete;

comparative example 2 is different from example 1 in that no reinforcing agent is added to the concrete.

Detection method

Initial setting time test

The setting time of the concrete was measured using a concrete penetration resistance meter, and the initial setting time of the concrete was measured as the following table.

Group of	Initial setting time (h)
		Example 1	50
Comparative example 1	6
		Comparative example 2	49

The concrete of example 1, comparative example 1 and comparative example 2 was tested using the rebound method for testing the compressive strength of concrete technical Specification JGJ/T23-2001J 115-2001, and the results are shown in the following table.

The following conclusions can be drawn from the two above tests:

1. As can be seen from the comparison of the initial setting time test results of example 1 and comparative example 1, the initial setting time of the concrete added with the super retarder is greatly improved.

2. As can be seen from the comparison of the concrete strength test results of example 1 and comparative example 2, cracks between aggregates in the concrete after the reinforcing agent is added are repaired, so that the strength of the concrete is improved.

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may occur to those skilled in the art without departing from the principle of the invention, and are considered to be within the scope of the invention.

Claims

1. the super-retarding concrete is characterized by comprising the following raw materials in parts by weight:

2. The super set retarding concrete of claim 1, wherein: the super retarder comprises the following components in percentage by weight:

3. The super set retarding concrete of claim 2, wherein: the emulsifier is one or more selected from OP-40 emulsifier, sodium dodecyl sulfate and GR-200 paraffin emulsifier.

4. The super set retarding concrete of claim 1, wherein: 3-5 parts by weight of an enhancer is added into the delayed coagulation concrete, and the enhancer comprises the following components in percentage by weight;

5. The super set retarding concrete according to claim 4, wherein: the reinforcing agent also comprises self-repairing microcapsules, and the reinforcing agent comprises the following components in percentage by weight:

6. the super set retarding concrete according to claim 5, wherein: the rolling aid comprises the following components in percentage by weight:

7. The super set retarding concrete according to claim 4, wherein: the core material of the self-repairing microcapsule is an acrylate core material; the wall material is urea-formaldehyde resin.