1. The ultra-high performance concrete is characterized by comprising the following components in parts by weight: 800-1000 parts of cement, 300-350 parts of silica fume, 100-200 parts of composite fiber, 150-200 parts of ground quartz sand, 10-15 parts of polycarboxylic acid water reducing agent, 1-3 parts of 2, 3-bis (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl phosphate sodium, 3-5 parts of tetramethyl tetraphenyl trisiloxane and 150-200 parts of water.

2. The ultra-high performance concrete according to claim 1, which comprises the following components in parts by weight: 900 parts of cement, 330 parts of silica fume, 150 parts of composite fiber, 170 parts of ground quartz sand, 13 parts of polycarboxylic acid water reducing agent, 2 parts of 2, 3-bis (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl phosphate sodium, 4 parts of tetramethyl tetraphenyl trisiloxane and 180 parts of water.

3. The ultra-high performance concrete according to claim 1, which comprises the following components in parts by weight: 850 parts of cement, 320 parts of silica fume, 160 parts of composite fiber, 180 parts of ground quartz sand, 12 parts of polycarboxylic acid water reducing agent, 2.5 parts of 2, 3-bis (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl phosphate sodium, 4.5 parts of tetramethyl tetraphenyl trisiloxane and 170 parts of water.

4. The ultra-high performance concrete as claimed in any one of claims 1 to 3, wherein the silica fume has a particle size distribution in the range of 0.1 to 0.15 μm and SiO₂The content is more than or equal to 98 percent.

5. The ultra-high performance concrete according to any one of claims 1 to 3, wherein the composite fiber is a fiber obtained by mixing and weaving polybenzimidazole fiber and polyisophthaloyl metaphenylene diamine fiber and carbonizing the fiber.

6. The ultra-high performance concrete according to claim 5, wherein the composite fiber has a diameter of 0.1 to 0.15mm and a length of 8 to 10 mm.

7. The ultra-high performance concrete according to any one of claims 1 to 3, wherein the particle size of the cement is 20 to 40 μm.

8. The preparation method of the ultra-high performance concrete is characterized by comprising the following steps:

s1, weighing the silica fume, the ground quartz sand, the cement, the water and the polycarboxylic acid water reducer in parts by mass, and stirring;

s2, adding the composite fiber in parts by mass and one half of sodium 2, 3-ditetradecanoylamino propyl 2-trimethylammonium ethyl phosphate, and stirring;

s3, adding the rest 2, 3-bis (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl sodium phosphate, and continuously stirring;

and S4, pouring the stirred ultrahigh-performance concrete into a mold and performing standard curing.

9. The method for preparing ultra-high performance concrete according to claim 8, wherein the stirring time in the step S1 is 3-5 min, the stirring time in the step S2 is 20-50S, and the stirring time in the step S3 is 1-3 min.

Background

Ultra-High Performance Concrete (UHPC) is also called as active powder Concrete, and is an Ultra-High strength cement-based material with High strength, High toughness and low porosity. The basic preparation principle of the material is that the fineness and activity of the components are improved, coarse aggregate is not used, and the defects (pores and microcracks) in the material are minimized, so that the ultrahigh strength and high durability are obtained.

The ultra-high performance concrete is the most innovative cement-based engineering material in the last thirty years, and realizes the large span of the performance of the engineering material. The UHPC buildings gradually develop towards the direction of super high-rise, multi-modeling, large-span and light weight, and the special buildings put higher requirements on various performances of concrete materials. The ultra-high performance concrete is widely applied to the building material industry by virtue of excellent performance.

However, the existing ultra-high performance concrete has poor toughness and burst problem, so that the concrete has poor durability and short service life. For filling of a mold, repairing of cracks and the like, UHPC slurry is required to have high fluidity.

Disclosure of Invention

The invention provides ultra-high performance concrete and a preparation method thereof, which solve the problem that the fluidity and the strength and the toughness are not matched in the prior art.

The technical scheme of the invention is as follows:

the ultra-high performance concrete comprises the following components in parts by weight: 800-1000 parts of cement, 300-350 parts of silica fume, 100-200 parts of composite fiber, 150-200 parts of ground quartz sand, 10-15 parts of polycarboxylic acid water reducing agent, 1-3 parts of 2, 3-bis (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl phosphate sodium, 3-5 parts of tetramethyl tetraphenyl trisiloxane and 150-200 parts of water.

As a further technical scheme, the composition comprises the following components in parts by weight: 900 parts of cement, 330 parts of silica fume, 150 parts of composite fiber, 170 parts of ground quartz sand, 13 parts of polycarboxylic acid water reducing agent, 2 parts of 2, 3-bis (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl phosphate sodium, 4 parts of tetramethyl tetraphenyl trisiloxane and 180 parts of water.

As a further technical scheme, the composition comprises the following components in parts by weight: 850 parts of cement, 320 parts of silica fume, 160 parts of composite fiber, 180 parts of ground quartz sand, 12 parts of polycarboxylic acid water reducing agent, 2.5 parts of 2, 3-bis (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl phosphate sodium, 4.5 parts of tetramethyl tetraphenyl trisiloxane and 170 parts of water.

As a further technical scheme, the particle size distribution range of the silica fume is 0.1-0.15 mu m, and SiO₂The content is more than or equal to 98 percent.

As a further technical scheme, the composite fiber is formed by mixing and weaving polybenzimidazole fiber and polyisophthaloyl metaphenylene diamine fiber and carbonizing the polybenzimidazole fiber and the polyisophthaloyl metaphenylene diamine fiber.

As a further technical scheme, the diameter of the composite fiber is 0.1-0.15 mm, and the length of the composite fiber is 8-10 mm.

As a further technical scheme, the particle size of the cement is 20-40 mu m.

The invention also provides a preparation method of the ultra-high performance concrete, which comprises the following steps:

s1, weighing the silica fume, the ground quartz sand, the cement, the water and the polycarboxylic acid water reducer in parts by mass, and stirring;

s2, adding the composite fiber in parts by mass and one half of sodium 2, 3-ditetradecanoylamino propyl 2-trimethylammonium ethyl phosphate, and stirring;

s3, adding the rest 2, 3-bis (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl sodium phosphate, and continuously stirring;

and S4, pouring the stirred ultrahigh-performance concrete into a mold and performing standard curing.

According to a further technical scheme, the stirring time in the step S1 is 3-5 min, the stirring time in the step S2 is 20-50S, and the stirring time in the step S3 is 1-3 min.

The invention has the beneficial effects that:

1. the concrete obtained by the components and the experimental method in the invention has excellent fluidity and mechanical property, and example 4 is the best example of comprehensive properties. The inventor adds 2, 3-di (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl sodium phosphate to improve the fluidity and the mechanical property of the concrete. The inventors believe that this is because sodium 2, 3-ditetradecanoylamino propyl 2-trimethylammonium ethyl phosphate introduces phosphoric acid groups and amide groups in addition to carboxyl groups into the system, and by introducing polar groups, sodium 2, 3-ditetradecanoylamino propyl 2-trimethylammonium ethyl phosphate has better lubricating effect than conventional polycarboxylic acid water reducing agents, so that the sliding resistance between cement particles is smaller and the fluidity is improved.

2. The inventor adds the carbonized organic fiber to improve the mechanical property of the concrete, but through experimental research, the inventor discovers that the workability of the concrete can be improved to a certain extent by carbonizing the organic fiber.

3. The inventor adopts tetramethyltetraphenyltrimersiloxane to replace the conventional polysiloxane antifoaming agent, and the tetramethyltetraphenyltrimersiloxane introduces a group with larger steric hindrance into a system, so that the coagulation effect among cement particles is hindered to a certain extent, and the slump of concrete is improved.

4. The inventor finds through experimental investigation that when the composite fiber is added step by step, a part of the 2, 3-ditetradecanoylamino propyl 2-trimethylammonium ethyl phosphate sodium is mixed with the composite fiber, so that the hydrophilicity and the dispersion promoting effect of the composite fiber can be better attached to the composite fiber, the compatibility of the composite fiber in a system can be improved, and finally the performance of the concrete in all aspects is better, and the residual 2, 3-ditetradecanoylamino propyl 2-trimethylammonium ethyl phosphate sodium can improve the fluidity of other components such as cement in the system. Moreover, the applicant has found that it is only necessary to add it in two steps, and if it is added in multiple batches, the resulting properties are hardly changed, which would rather complicate the manufacturing process.

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 inventive step, are intended to be within the scope of the present invention.

In the examples and comparative examples of the present invention, if not specifically mentioned, the particle size distribution of the silica fume is in the range of 0.1 to 0.15. mu.m, SiO₂The content is more than or equal to 98%, the particle size of the cement is 20-40 mu m, and the composite fiber is a polybenzimidazole fiber and polyisophthaloyl metaphenylene diamine fiber 1: 1, performing mixed weaving, carbonizing the fiber according to a conventional carbonization process and a temperature gradient, setting the carbonization temperature to be 800-1000 ℃, adjusting the drafting speed to enable the diameter of the finally obtained composite fiber to be 0.1-0.15 mm, and shearing the composite fiber to be 8-10 mm in length. Polycarboxylic acid water reducers are available from the Technology of Wangpenpene, Beijing.

Example 1

Preparing materials: 800 parts of cement, 300 parts of silica fume, 100 parts of composite fiber, 150 parts of ground quartz sand, 10 parts of polycarboxylic acid water reducing agent, 1 part of 2, 3-bis (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl phosphate sodium, 3 parts of tetramethyl tetraphenyl trisiloxane and 150 parts of water.

S1, weighing the silica fume, the ground quartz sand, the cement, the water and the polycarboxylic acid water reducer in parts by mass, and stirring for 3 min;

s2, adding the composite fiber in parts by mass and one half of sodium 2, 3-ditetradecanoylamino propyl 2-trimethylammonium ethyl phosphate, and stirring for 30S;

s3, adding the rest 2, 3-bis (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl phosphate sodium, and continuing stirring for 1 min;

and S4, pouring the stirred ultrahigh-performance concrete into a mold and performing standard curing.

Example 2

Preparing materials: 1000 parts of cement, 350 parts of silica fume, 200 parts of composite fiber, 200 parts of ground quartz sand, 15 parts of polycarboxylic acid water reducing agent, 3 parts of 2, 3-bis (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl phosphate sodium, 5 parts of tetramethyl tetraphenyl trisiloxane and 200 parts of water.

S1, weighing the silica fume, the ground quartz sand, the cement, the water and the polycarboxylic acid water reducer in parts by mass, and stirring for 5 min;

s2, adding the composite fiber in parts by mass and one half of 2, 3-di (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl sodium phosphate, and stirring for 50S;

s3, adding the rest 2, 3-bis (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl phosphate sodium, and continuing stirring for 3 min;

and S4, pouring the stirred ultrahigh-performance concrete into a mold and performing standard curing.

Example 3

Preparing materials: 900 parts of cement, 330 parts of silica fume, 150 parts of composite fiber, 170 parts of ground quartz sand, 13 parts of polycarboxylic acid water reducing agent, 2 parts of 2, 3-bis (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl phosphate sodium, 4 parts of tetramethyl tetraphenyl trisiloxane and 180 parts of water.

S1, weighing the silica fume, the ground quartz sand, the cement, the water and the polycarboxylic acid water reducer in parts by mass, and stirring for 4 min;

s2, adding the composite fiber in parts by mass and one half of 2, 3-di (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl sodium phosphate and stirring for 40S;

s3, adding the rest 2, 3-bis (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl phosphate sodium, and continuing stirring for 2 min;

and S4, pouring the stirred ultrahigh-performance concrete into a mold and performing standard curing.

Example 4

Preparing materials: 850 parts of cement, 320 parts of silica fume, 160 parts of composite fiber, 180 parts of ground quartz sand, 12 parts of polycarboxylic acid water reducing agent, 2.5 parts of 2, 3-bis (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl phosphate sodium, 4.5 parts of tetramethyl tetraphenyl trisiloxane and 170 parts of water.

S1, weighing the silica fume, the ground quartz sand, the cement, the water and the polycarboxylic acid water reducer in parts by mass, and stirring for 4 min;

s2, adding the composite fiber in parts by mass and one half of 2, 3-di (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl sodium phosphate and stirring for 40S;

s3, adding the rest 2, 3-bis (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl phosphate sodium, and continuing stirring for 2 min;

and S4, pouring the stirred ultrahigh-performance concrete into a mold and performing standard curing.

Example 5

Preparing materials: 850 parts of cement, 320 parts of silica fume, 160 parts of composite fiber, 180 parts of ground quartz sand, 12 parts of polycarboxylic acid water reducing agent, 2.5 parts of 2, 3-bis (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl phosphate sodium, 4.5 parts of tetramethyl tetraphenyl trisiloxane and 170 parts of water.

S1, weighing the silica fume, the ground quartz sand, the cement, the water and the polycarboxylic acid water reducer in parts by mass, and stirring for 4 min;

s2, adding the composite fiber in parts by mass and one half of 2, 3-di (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl sodium phosphate and stirring for 40S;

s3, adding the rest 2, 3-bis (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl phosphate sodium, and continuing stirring for 2 min;

and S4, pouring the stirred ultrahigh-performance concrete into a mold and performing standard curing.

Comparative example 1

Preparing materials: 850 parts of cement, 320 parts of silica fume, 160 parts of composite fiber, 180 parts of ground quartz sand, 14.5 parts of polycarboxylic acid water reducing agent, 4.5 parts of tetramethyl tetraphenyl trisiloxane and 170 parts of water.

S1, weighing the silica fume, the ground quartz sand, the cement, the water and the 12 parts of polycarboxylic acid water reducing agent in parts by mass, and stirring for 4 min;

s2, adding the composite fiber in parts by mass and 1 part of polycarboxylic acid water reducing agent, and stirring for 40S;

s3, adding the residual polycarboxylic acid water reducing agent, and continuing stirring for 2 min;

and S4, pouring the stirred ultrahigh-performance concrete into a mold and performing standard curing.

Comparative example 2

The composite fiber was not carbonized as compared with example 4, and the rest was the same as example 4.

Comparative example 3

The same procedure as in example 4 was repeated except that polydimethylsiloxane was used in the same amount as in example 4 instead of tetramethyltetraphenyltrimersiloxane.

Comparative example 4

Preparing materials: 850 parts of cement, 320 parts of silica fume, 160 parts of composite fiber, 180 parts of ground quartz sand, 12 parts of polycarboxylic acid water reducing agent, 2.5 parts of 2, 3-bis (tetradecyl carbonylamino) propyl 2-trimethyl ammonium ethyl phosphate sodium, 4.5 parts of tetramethyl tetraphenyl trisiloxane and 170 parts of water.

S1, weighing the silica fume, the ground quartz sand, the cement, the water and the polycarboxylic acid water reducer in parts by mass, and stirring for 4 min;

s2, adding the composite fiber and 2, 3-bis (tetradecyl amido) propyl 2-trimethyl ammonium ethyl sodium phosphate, and stirring for 2 min;

and S3, pouring the stirred ultrahigh-performance concrete into a mold and performing standard curing.

The performance of the examples and the comparative examples was tested with reference to standard GB/T50081-2016, the mechanical properties of ordinary concrete, and the test results are shown in Table 1.

TABLE 1 test results of ultra high Performance concrete of examples and comparative examples

The concrete obtained by the components and the experimental method of the invention has excellent fluidity and mechanical property, and the example 4 is the best example of the comprehensive properties. In comparative example 1, the concrete prepared by adding only the polycarboxylic acid water reducing agent without adding 2, 3-bis (tetradecylamino) propyl 2-trimethylammonioethyl sodium phosphate has poorer fluidity and poorer mechanical properties compared with example 4, and the inventor believes that the concrete prepared by adding the polycarboxylic acid water reducing agent only has smaller sliding resistance between cement particles and improved fluidity because 2, 3-bis (tetradecylamino) propyl 2-trimethylammonioethyl sodium phosphate is better in lubricating effect than the conventional polycarboxylic acid water reducing agent by introducing the polar group by introducing the phosphoric acid group and the amide group into the system in addition to the carboxyl group.

Compared with example 4, the organic fiber in comparative example 2 is not carbonized, the inventor finds that the carbonized fiber has lower mechanical property and lower slump compared with the protofilament, and the inventor conducts a comparative experiment by adding the carbonized fiber and the non-carbonized fiber to improve the mechanical property of the concrete, but through experimental research, the organic fiber is carbonized to improve the workability of the concrete to a certain extent.

Compared with the embodiment 4, the performance of the conventional polysiloxane antifoaming agent is reduced in all aspects in the comparative example 3, and a group with larger steric hindrance is introduced into the system by the tetramethyl tetraphenyl trisiloxane, so that the coagulation effect among cement particles is hindered to a certain extent, and the slump of concrete is improved.

Comparative example 4 is a preparation method for performing one-step addition, and the inventor finds through experimental study that when the composite fiber is added step by step, a part of sodium 2, 3-bis (tetradecanoylamino) propyl 2-trimethylammonium ethyl phosphate is mixed with the composite fiber, so that the hydrophilicity and the dispersion promoting effect of the sodium 2, 3-bis (tetradecanoylamino) propyl 2-trimethylammonium ethyl phosphate can be better attached to the composite fiber, the compatibility of the composite fiber in a system can also be improved, and finally, the performance of concrete in all aspects is better, and the flowability of other components such as cement in the system can be improved by the rest sodium 2, 3-bis (tetradecanoylamino) propyl 2-trimethylammonium ethyl phosphate. Moreover, the applicant has found that it is only necessary to add it in two steps, and if it is added in multiple batches, the resulting properties are hardly changed, which would rather complicate the manufacturing process.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions, improvements, etc. within the spirit and principle of the present invention should be included in the protection scope of the present invention.