CN106116362A - A kind of carbon fiber composite graphite alkene strengthens the preparation method of regeneration concrete - Google Patents

Abstract

A preparation method of carbon fiber composite graphene reinforced recycled concrete, first prepare materials according to the following mass ratio, cement: sand: coarse aggregate: water: nanomaterial: water reducer: fiber material = 1: (1.4～1.6):( 2.6～3):(0.28～0.32):(0.0001～0.0005):(0.01～0.05):(0.012～0.016); then mix nanomaterials, water reducing agent and water, and perform ultrasonic dispersion to obtain a suspension; then Put cement, fiber material, sand and coarse aggregate in a mixer, and stir evenly to obtain a mixture; finally, add the suspension to the mixture, and stir to obtain carbon fiber composite graphene-reinforced recycled concrete, the nanomaterial is graphene, and the fiber material is nano Carbon fiber, the concrete prepared by the invention is denser, and the flexural strength and compressive strength are greatly improved.

Description

A preparation method of carbon fiber composite graphene reinforced recycled concrete

technical field

The invention relates to the technical field of recycled concrete, in particular to a preparation method of carbon fiber composite graphene reinforced recycled concrete.

Background technique

The main problem of traditional concrete is brittleness, many micro-cracks and micro-pores in concrete, and weak connection interface. Although, in order to solve this problem, many experts at home and abroad have mixed fiber materials, active minerals and high-efficiency water reducers in concrete. Although it can improve the performance of concrete to a certain extent, the effect is very small.

Graphene material is a newly emerging high-performance material, which is currently the thinnest and strongest nanomaterial in the world. Its super strength and toughness, super large specific surface area are favored by people; the use of graphene in recycled concrete can not only solve the defects caused by traditional concrete, but also push building materials to a new height, not only It effectively solves the concrete waste, and also enables the effective application of graphene. Under the new situation, the performance of recycled concrete has been greatly improved. The market application prospect is broad.

Carbon fiber has excellent properties such as size effect, surface effect and volume effect, and is widely used in various industries. The use of carbon fiber to solve the mechanical properties of recycled concrete has greatly promoted the development of concrete technology.

At present, there is no literature report on the joint use of carbon fiber and graphene in recycled concrete.

Contents of the invention

In order to overcome the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a method for preparing carbon fiber composite graphene-reinforced recycled concrete. The prepared concrete is denser, and the flexural strength and compressive strength are greatly improved.

In order to achieve the above object, the technical scheme that the present invention takes is:

A preparation method of carbon fiber composite graphene reinforced recycled concrete, comprising the following steps:

Step 1: prepare materials according to the following mass ratio, cement: sand: coarse aggregate: water: nano material: water reducer: fiber material = 1: (1.4～1.6): (2.6～3): (0.28～0.32): (0.0001～0.0005):(0.01～0.05):(0.012～0.016);

Step 2: Mix nanomaterials, water reducing agent and water, and perform ultrasonic dispersion for 30 to 60 minutes to obtain a suspension;

Step 3: Put cement, fiber material, sand and coarse aggregate in a mixer, and stir for 3 to 4 minutes to make it evenly stirred to obtain a mixture;

Step 4: Add the suspension prepared in Step 2 to the mixture in Step 3, and stir for 3 to 5 minutes to obtain carbon fiber composite graphene-reinforced recycled concrete;

The nanomaterial is graphene with a particle size of 0.6-1nm;

The fiber material is carbon nanofiber with an average diameter of 150nm and a length of 30-100um.

The cement is 42.5R ordinary Portland cement.

The sand is medium sand with an average particle size of 0.25-0.5 mm.

The coarse aggregate is a mixture of natural gravel and waste concrete in any proportion, and the maximum particle size of the coarse aggregate is less than 31.5 mm.

The water reducer is a carboxylic acid-based high-efficiency water reducer with a water reducing efficiency of 20% to 30%.

The beneficial effects of the present invention are:

Using waste concrete as part of the aggregate to prepare concrete not only effectively solves the problem of reuse of construction waste, but also provides an effective solution to the increasingly tight shortage of concrete raw materials, which is economical and meets the requirements of use.

As a new type of nanomaterial, graphene not only has higher strength and better toughness than ordinary nanomaterials, but also has a super high specific surface area. Applying graphene to recycled concrete not only effectively fills the micro gaps in the interface between coarse aggregate and cement in recycled concrete , and make up for the micro-pores that appear during the concrete mixing process. The concrete is denser, the compressive strength is higher, the microstructure is denser, and the mechanical and physical properties of recycled concrete are improved.

Utilizing the advantages of low density, high specific strength, large aspect ratio, large specific surface area, and compact structure of carbon nanofibers, economical, practical, and environmentally friendly green high-performance recycled concrete can be realized through appropriate mix ratio design.

Description of drawings

Figure 1 is a broken line diagram of the cumulative sieving of coarse aggregate.

detailed description:

The present invention is described in detail below in conjunction with embodiment.

The coarse aggregate used in all examples is partly from natural stones and partly from waste concrete. After crushing, impurity removal, cleaning and screening, its quality meets the requirements of "Recycled Coarse Aggregate for Concrete" GB/T 25177-2010, Coarse Aggregate The cumulative screening line chart of materials is shown in Figure 1, and the specific screening conditions are shown in Table 1:

Table 1

According to the calculation of JGJ52-2006, it can be seen that for the coarse aggregate with particle size within 5mm-31.5mm, the value of unevenness coefficient Ku is between (0.37,0.69), and the value of curvature coefficient Kc is between (0.80,1.53). Referring to Table 2, it can be seen from Table 2 that the unevenness coefficient and curvature coefficient of recycled coarse aggregates with different service life are within the above range, which meets the requirements of particle gradation, indicating that the aggregate gradation is good.

Table 2

According to the requirements of fine aggregate particle grading in JGJ52-2006, the medium sand was sieved and analyzed, and the analysis results are shown in Table 3. It can be seen that the particle gradation of the medium sand is good, so the medium sand is used to prepare recycled concrete.

Table 3 Results of medium sand particle grading test

The basic performance of the nanomaterial graphene that embodiment adopts is as follows:

Table 4 Basic properties of graphene

Embodiment 1, a kind of preparation method of carbon fiber composite graphene reinforced recycled concrete comprises the following steps:

Step 1: prepare materials according to the following mass ratio, cement: sand: coarse aggregate: water: nano material: water reducer: fiber material = 1: 1.4: 2.6: 0.28: 0.0001: 0.02: 0.012, the cement is 42.5 R ordinary Portland cement, the sand is medium sand, the coarse aggregate is a mixture of natural crushed stone and recycled aggregate with a replacement rate of 30%, and the replacement rate is the weight of waste concrete to the total mass of coarse aggregate The nanomaterial is graphene with a particle size of 0.6-1nm, the water reducer is a carboxylic acid-based high-efficiency water reducer, and the water reducing efficiency is 20% to 30%, and the fiber is nano Carbon fibers with an average diameter of 150nm and a length of 30-100um;

Step 2: Mix nanomaterials, water reducing agent and water, and perform ultrasonic dispersion for 60 minutes to obtain a suspension;

Step 3: Put cement, fiber material, sand and coarse aggregate in a mixer, and stir for 3 minutes to make it evenly stirred to obtain a mixture;

Step 4: Add the suspension prepared in Step 2 to the mixture in Step 3, and stir for 5 minutes to make it meet the performance requirements during pouring, and obtain carbon fiber composite graphene-reinforced recycled concrete.

Beneficial effects of this embodiment: the obtained graphene-enhanced recycled concrete has a technical index of 28 days age: the compressive strength reaches 68.3MPa, which is 14.2% higher than that of ordinary concrete. The flexural strength is 17% higher than that of ordinary concrete.

Embodiment 2, a kind of preparation method of carbon fiber composite graphene reinforced recycled concrete comprises the following steps:

Step 1: prepare materials according to the following mass ratio, cement: sand: coarse aggregate: water: nanomaterial: water reducer: fiber material = 1: 1.5: 2.8: 0.30: 0.0002: 0.01: 0.014, the cement is 42.5 R ordinary Portland cement, the sand is medium sand, the coarse aggregate is a mixture of natural crushed stone and recycled aggregate with a replacement rate of 30%, and the replacement rate is the weight of waste concrete to the total mass of coarse aggregate The nanomaterial is graphene with a particle size of 0.6-1nm, the water reducer is a carboxylic acid-based high-efficiency water reducer, and the water reducing efficiency is 20% to 30%, and the fiber is nano Carbon fibers with an average diameter of 150nm and a length of 30-100um;

Step 2: Mix nanomaterials, water reducing agent and water, and perform ultrasonic dispersion for 50 minutes to obtain a suspension;

Step 3: Put cement, fiber material, sand and coarse aggregate in a mixer, and stir for 3 minutes to make it evenly stirred to obtain a mixture;

Step 4: Add the suspension prepared in Step 2 to the mixture in Step 3, and stir for 4 minutes to make it meet the performance requirements during pouring, and obtain carbon fiber composite graphene-reinforced recycled concrete.

Beneficial effects of this embodiment: the obtained graphene-enhanced recycled concrete has a technical index of 28 days age: the compressive strength reaches 70.3MPa, which is 16.2% higher than that of ordinary concrete. The flexural strength is 18% higher than that of ordinary concrete.

Embodiment 3, a kind of preparation method of carbon fiber composite graphene reinforced recycled concrete, comprises the following steps:

Step 1: prepare materials according to the following mass ratio, cement: sand: coarse aggregate: water: nano material: water reducer: fiber material = 1: 1.5: 2.8: 0.28: 0.0003: 0.03: 0.016, the cement is 42.5 R ordinary Portland cement, the sand is medium sand, the coarse aggregate is a mixture of natural crushed stone and recycled aggregate with a replacement rate of 50%, and the replacement rate is the weight of waste concrete to the total mass of coarse aggregate The nanomaterial is graphene with a particle size of 0.6-1nm, the water reducer is a carboxylic acid-based high-efficiency water reducer, and the water reducing efficiency is 20% to 30%, and the fiber is nano Carbon fibers with an average diameter of 150nm and a length of 30-100um;

Step 2: Mix nanomaterials, water reducing agent and water, and perform ultrasonic dispersion for 40 minutes to obtain a suspension;

Step 3: Put cement, fiber material, sand and coarse aggregate in a mixer, and stir for 4 minutes to make it evenly stirred to obtain a mixture;

Step 4: Add the suspension prepared in Step 2 to the mixture in Step 3, and stir for 3 minutes to make it meet the performance requirements during pouring, and obtain carbon fiber composite graphene-reinforced recycled concrete.

Beneficial effects of this embodiment: The obtained graphene-enhanced recycled concrete has a technical index of 28 days of age: the compressive strength reaches 67.3MPa, which is 13.9% higher than that of ordinary concrete. The flexural strength is 15.2% higher than that of ordinary concrete.

Embodiment 4, a kind of preparation method of carbon fiber composite graphene reinforced recycled concrete, comprises the following steps:

Step 1: prepare materials according to the following mass ratio, cement: sand: coarse aggregate: water: nano material: water reducer: fiber material = 1: 1.6: 3.0: 0.32: 0.0004: 0.03: 0.016, the cement is 42.5 R ordinary Portland cement, the sand is medium sand, the coarse aggregate is a mixture of natural crushed stone and recycled aggregate with a replacement rate of 70%, and the replacement rate is the weight of waste concrete to the total mass of coarse aggregate The nanomaterial is graphene with a particle size of 0.6-1nm, the water reducer is a carboxylic acid-based high-efficiency water reducer, and the water reducing efficiency is 20% to 30%, and the fiber is nano Carbon fibers with an average diameter of 150nm and a length of 30-100um;

Step 2: Mix nanomaterials, water reducing agent and water, and perform ultrasonic dispersion for 30 minutes to obtain a suspension;

Step 3: Put cement, fiber material, sand and coarse aggregate in a mixer, and stir for 4 minutes to make it evenly stirred to obtain a mixture;

Step 4: Add the suspension prepared in Step 2 to the mixture in Step 3, and stir for 5 minutes to make it meet the performance requirements during pouring, and obtain carbon fiber composite graphene-reinforced recycled concrete.

Beneficial effects of this embodiment: the obtained graphene-enhanced recycled concrete has a technical index of 28 days age: the compressive strength reaches 66.2MPa, which is 13.4% higher than that of ordinary concrete. The flexural strength is 14.2% higher than that of ordinary concrete.

Embodiment 5, a kind of preparation method of carbon fiber composite graphene reinforced recycled concrete, comprises the following steps:

Step 1: prepare materials according to the following mass ratio, cement: sand: coarse aggregate: water: nano material: water reducer: fiber material = 1: 1.6: 2.9: 0.32: 0.0005: 0.05: 0.016, the cement is 42.5 R ordinary Portland cement, the sand is medium sand, the coarse aggregate is a mixture of natural crushed stone and recycled aggregate with a replacement rate of 100%, and the replacement rate is the mass of waste concrete to the total mass of coarse aggregate The nanomaterial is graphene with a particle size of 0.6-1nm, the water reducer is a carboxylic acid-based high-efficiency water reducer, and the water reducing efficiency is 20% to 30%, and the fiber is nano Carbon fibers with an average diameter of 150nm and a length of 30-100um;

Step 2: Mix nanomaterials, water reducing agent and water, and perform ultrasonic dispersion for 60 minutes to obtain a suspension;

Step 3: Put cement, fiber material, sand and coarse aggregate in a mixer, and stir for 4 minutes to make it evenly stirred to obtain a mixture;

Step 4: Add the suspension prepared in Step 2 to the mixture in Step 3, and stir for 5 minutes to make it meet the performance requirements during pouring, and obtain carbon fiber composite graphene-reinforced recycled concrete.

Beneficial effects of this embodiment: The obtained graphene-enhanced recycled concrete has a technical index of 28 days age: the compressive strength reaches 65.2MPa, which is 12.3% higher than that of ordinary concrete. The flexural strength is 13% higher than that of ordinary concrete.

Claims (9)

1. a preparation method of carbon fiber composite graphene reinforced recycled concrete, is characterized in that, may further comprise the steps: Step 1: prepare materials according to the following mass ratio, cement: sand: coarse aggregate: water: nano material: water reducer: fiber material = 1: (1.4～1.6): (2.6～3): (0.28～0.32): (0.0001～0.0005):(0.01～0.05):(0.012～0.016); Step 2: Mix nanomaterials, water reducing agent and water, and perform ultrasonic dispersion for 30 to 60 minutes to obtain a suspension; Step 3: Put cement, fiber material, sand and coarse aggregate in a mixer, and stir for 3 to 4 minutes to make it evenly stirred to obtain a mixture; Step 4: Add the suspension prepared in Step 2 to the mixture in Step 3, and stir for 3 to 5 minutes to obtain carbon fiber composite graphene-reinforced recycled concrete; The nanomaterial is graphene with a particle size of 0.6-1nm; The fiber material is carbon nanofiber with an average diameter of 150nm and a length of 30-100um. 2. the preparation method of a kind of carbon fiber composite graphene reinforced recycled concrete according to claim 1, is characterized in that: described cement is 42.5R ordinary portland cement. 3. A method for preparing carbon fiber composite graphene reinforced recycled concrete according to claim 1, characterized in that: the sand is medium sand with an average particle size of 0.25-0.5 mm. 4. the preparation method of a kind of carbon fiber composite graphene reinforced recycled concrete according to claim 1, is characterized in that: described coarse aggregate is the mixture of natural crushed stone and waste concrete, and the maximum particle diameter of coarse aggregate is Less than 31.5mm. 5. A method for preparing carbon fiber composite graphene-reinforced recycled concrete according to claim 1, wherein the water reducing agent is a carboxylic acid-based high-efficiency water reducing agent, and the water reducing efficiency is 20% to 30%. . 6. the preparation method of a kind of carbon fiber composite graphene reinforced recycled concrete according to claim 1, is characterized in that, comprises the following steps: Step 1: prepare materials according to the following mass ratio, cement: sand: coarse aggregate: water: nano material: water reducer: fiber material = 1: 1.4: 2.6: 0.28: 0.0001: 0.02: 0.012, the cement is 42.5 R ordinary Portland cement, the sand is medium sand, the coarse aggregate is a mixture of natural crushed stone and recycled aggregate with a replacement rate of 30%, and the replacement rate is the weight of waste concrete to the total mass of coarse aggregate The nanomaterial is graphene with a particle size of 0.6-1nm, the water reducer is a carboxylic acid-based high-efficiency water reducer, and the water reducing efficiency is 20% to 30%, and the fiber is nano Carbon fibers with an average diameter of 150nm and a length of 30-100um; Step 2: Mix nanomaterials, water reducing agent and water, and perform ultrasonic dispersion for 60 minutes to obtain a suspension; Step 3: Put cement, fiber material, sand and coarse aggregate in a mixer, and stir for 3 minutes to make it evenly stirred to obtain a mixture; Step 4: Add the suspension prepared in Step 2 to the mixture in Step 3, and stir for 5 minutes to make it meet the performance requirements during pouring, and obtain carbon fiber composite graphene-reinforced recycled concrete. 7. the preparation method of a kind of carbon fiber composite graphene reinforced recycled concrete according to claim 1, is characterized in that, comprises the following steps: Step 1: prepare materials according to the following mass ratio, cement: sand: coarse aggregate: water: nanomaterial: water reducer: fiber material = 1: 1.5: 2.8: 0.30: 0.0002: 0.01: 0.014, the cement is 42.5 R ordinary Portland cement, the sand is medium sand, the coarse aggregate is a mixture of natural crushed stone and recycled aggregate with a replacement rate of 30%, and the replacement rate is the weight of waste concrete to the total mass of coarse aggregate The nanomaterial is graphene with a particle size of 0.6-1nm, the water reducer is a carboxylic acid-based high-efficiency water reducer, and the water reducing efficiency is 20% to 30%, and the fiber is nano Carbon fibers with an average diameter of 150nm and a length of 30-100um; Step 2: Mix nanomaterials, water reducing agent and water, and perform ultrasonic dispersion for 50 minutes to obtain a suspension; Step 3: Put cement, fiber material, sand and coarse aggregate in a mixer, and stir for 3 minutes to make it evenly stirred to obtain a mixture; Step 4: Add the suspension prepared in Step 2 to the mixture in Step 3, and stir for 4 minutes to make it meet the performance requirements during pouring, and obtain carbon fiber composite graphene-reinforced recycled concrete. 8. the preparation method of a kind of carbon fiber composite graphene reinforced recycled concrete according to claim 1, is characterized in that, comprises the following steps: Step 1: prepare materials according to the following mass ratio, cement: sand: coarse aggregate: water: nano material: water reducer: fiber material = 1: 1.5: 2.8: 0.28: 0.0003: 0.03: 0.016, the cement is 42.5 R ordinary Portland cement, the sand is medium sand, the coarse aggregate is a mixture of natural crushed stone and recycled aggregate with a replacement rate of 50%, and the replacement rate is the weight of waste concrete to the total mass of coarse aggregate The nanomaterial is graphene with a particle size of 0.6-1nm, the water reducer is a carboxylic acid-based high-efficiency water reducer, and the water reducing efficiency is 20% to 30%, and the fiber is nano Carbon fibers with an average diameter of 150nm and a length of 30-100um; Step 2: Mix nanomaterials, water reducing agent and water, and perform ultrasonic dispersion for 40 minutes to obtain a suspension; Step 3: Put cement, fiber material, sand and coarse aggregate in a mixer, and stir for 4 minutes to make it evenly stirred to obtain a mixture; Step 4: Add the suspension prepared in Step 2 to the mixture in Step 3, and stir for 3 minutes to make it meet the performance requirements during pouring, and obtain carbon fiber composite graphene-reinforced recycled concrete. 9. the preparation method of a kind of carbon fiber composite graphene reinforced recycled concrete according to claim 1, is characterized in that, comprises the following steps: Step 1: prepare materials according to the following mass ratio, cement: sand: coarse aggregate: water: nano material: water reducer: fiber material = 1: 1.6: 3.0: 0.32: 0.0004: 0.03: 0.016, the cement is 42.5 R ordinary Portland cement, the sand is medium sand, the coarse aggregate is a mixture of natural crushed stone and recycled aggregate with a replacement rate of 70%, and the replacement rate is the weight of waste concrete to the total mass of coarse aggregate The nanomaterial is graphene with a particle size of 0.6-1nm, the water reducer is a carboxylic acid-based high-efficiency water reducer, and the water reducing efficiency is 20% to 30%, and the fiber is nano Carbon fibers with an average diameter of 150nm and a length of 30-100um; Step 2: Mix nanomaterials, water reducing agent and water, and perform ultrasonic dispersion for 30 minutes to obtain a suspension; Step 3: Put cement, fiber material, sand and coarse aggregate in a mixer, and stir for 4 minutes to make it evenly stirred to obtain a mixture; Step 4: Add the suspension prepared in Step 2 to the mixture in Step 3, and stir for 5 minutes to make it meet the performance requirements during pouring, and obtain carbon fiber composite graphene-reinforced recycled concrete.