CN105948665B - A kind of morning strong lower shrinkage high tenacity cement base engineering material and preparation method thereof - Google Patents

Abstract

The invention belongs to the field of building materials. An early-strength, low-shrinkage, high-toughness cement-based engineering material is characterized in that it consists of sulphoaluminate cement, ordinary Portland cement, silica fume, steel fiber, polyvinyl alcohol fiber, water, water reducing agent, early-strength The content of each raw material is: sulphoaluminate cement 460~500kg/m ³ , ordinary portland cement 50~70kg/m ³ , silica fume 50~70kg/m 3 ^3. Steel fiber 40~60kg/m ³ , polyvinyl alcohol fiber 8~10kg/m ³ , water 200~220kg/m ³ , water reducing agent 7.0~7.4kg/m ³ , early strength agent 0.2~0.22kg/m 3 ^3. Retarder 1.7~1.9kg/m ³ , river sand 1180~1220kg/m ³ . The prepared cement-based engineering material has good working performance, high early strength, large later strength growth, excellent mechanical properties, volume stability, high toughness, good mechanical properties and durability, and great practical application value.

Description

A kind of cement-based engineering material with early strength, low shrinkage and high toughness and preparation method thereof

technical field

The invention belongs to the field of building materials, and in particular relates to an early-strength, low-shrinkage, high-toughness cement-based engineering material and a preparation method thereof.

Background technique

Cement-based engineering material (engineered cementitious composite, ECC) is a new type of cement-based composite material for engineering based on the optimal design of microscopic physical and mechanical principles. Its design concept was first proposed by Li Victor C of the University of Michigan in the 1990s. It is made of special organic synthetic fiber as one of the main materials, plus a special blending process, which has better tensile, wear-resistant, toughness, acid and alkali resistance, compactness, impact resistance, etc. than traditional cement-based materials. A series of high-quality features have been widely used in projects such as concrete structure protection, bridge deck repair, and non-expandable bridge decks.

However, ordinary cement-based engineering materials also have the following disadvantages: 1) they do not contain coarse aggregate, and the cement paste has a large content and large shrinkage, which is easy to cause debonding and cracking between the repair layer and the base layer; 2) the high content of PVA fiber, the viscosity Large, difficult to construct; 3) high cost.

These shortcomings limit its large-scale application in the field of rapid repair of concrete structures.

Contents of the invention

The object of the present invention is to provide a kind of cement-based engineering material with early strength, low shrinkage and high toughness and its preparation method. The prepared cement-based engineering material has good working performance, high early strength and large later strength growth, and has good mechanical properties and Durability.

In order to achieve the above object, the technical solution adopted by the present invention is: a cement-based engineering material with early strength, low shrinkage and high toughness, which is characterized in that it is composed of sulphoaluminate cement, ordinary Portland cement, silica fume, steel fiber , polyvinyl alcohol fiber, water, water reducing agent, early strength agent, retarder and river sand raw materials, the content of each raw material is: sulfoaluminate cement 460 ~ 500kg/m ³ 50～70kg/m ³ , silica fume 50～70kg/m ³ , steel fiber 40～60kg/m ³ , polyvinyl alcohol fiber 8～10kg/m ³ , water 200～220kg/m ³ , water reducing agent 7.0～7.4 kg/m ³ , early strength agent 0.2-0.22kg/m ³ , retarder 1.7-1.9kg/m ³ , river sand 1180-1220kg/m ³ .

According to the above scheme, the sulphoaluminate cement is R.SAC42.5 sulphoaluminate cement, with a specific surface area ≥ 400m ² /kg, a sieve residue of 0.08mm ≤ 10.0%, and a free expansion rate of 0.2% ≤ 28d ≤ 0.4%. .

According to the above scheme, the ordinary Portland cement (ie Portland cement) is PO42.5 Portland cement with a specific surface area ≥ 300m ² /kg.

According to the above scheme, the silica fume is micro silica fume, the specific surface area is ≥20000m ² /kg, and the activity index is ≥90%.

According to the above scheme, the steel fibers are short copper-coated steel fibers with a diameter of 0.2 mm, a length of 10 mm, a tensile strength ≥ 1800 MPa, and an elastic modulus ≥ 200 MPa.

According to the above scheme, the length of the polyvinyl alcohol fiber is 12 mm, the aspect ratio is 316, the breaking strength is ≥ 1600 MPa, and the elastic modulus is ≥ 28 GPa.

According to the above plan, the water reducer is an ultra-dispersed viscosity-reducing polycarboxylic acid-based high-efficiency water reducer with a molecular formula of (-CH ₂ CR ₁ COOM-) _x {CH ₂ CR ₁ COO-[(CH ₂ CH ₂ O) _n ]-R ₂ } _y , molecular weight 15000-20000, x=25-40, y=30-45, n=10-15.

According to the above scheme, the early strength agent is lithium carbonate, industrial grade, with a content ≥ 98% (by mass).

According to the above scheme, the retarder is boric acid, industrial grade, with a content ≥ 98% (by mass).

According to the above scheme, the mud content of the river sand is 0% (mass), the particle size is not greater than 1.18mm, the fineness modulus is ≤1.7, and the apparent density is ≤2700kg/m ³ .

The above-mentioned preparation method of early-strength, low-shrinkage and high-toughness cement-based engineering material is characterized in that it comprises the following steps:

1) According to the content of each raw material: sulphoaluminate cement 460~500kg/m ³ , ordinary Portland cement 50~70kg/m ³ , silica fume 50~70kg/m ³ , steel fiber 40~60kg/m ³ , polyvinyl alcohol fiber 8~10kg/m ³ , water 200~220kg/m ³ , water reducer 7.0~7.4kg/m ³ , early strength agent 0.2~0.22kg/m ³ , retarder 1.7~1.9kg/m 3 m ³ , river sand 1180～1220kg/m ³ , weigh raw materials;

2) Take part of the water and heat it into warm water (the temperature of the warm water is 45-60° C.), respectively dissolve the early strength agent (lithium carbonate) and the retarder (boric acid) in the warm water {the amount of water is enough to dissolve, and the total Within the amount of water (water 200～220kg/m ³ ), not strictly required}, lithium carbonate solution and boric acid solution are obtained;

3) Mix sulphoaluminate cement, ordinary Portland cement, silica fume and river sand dry-mixed for 1 minute to obtain a mixture; add the remaining water to the obtained mixture (that is, deduct the water for dissolving lithium carbonate and boric acid) , water reducer, stirring for 2-3min to prepare a mixed slurry;

4) Add the steel fiber and polyvinyl alcohol fiber evenly into the mixed slurry respectively, and stir for 3 minutes until the mixed fiber is evenly dispersed in the mixed slurry to obtain a fiber-containing mixed slurry;

5) adding the lithium carbonate solution and the boric acid solution into the fiber-containing mixed slurry obtained in step 4), and stirring for 1 min;

6) Pour the slurry obtained in 5) into a mold to form it, let it stand for 4 to 5 hours, demould it, and perform curing to obtain a cement-based engineering material with early strength, low shrinkage and high toughness.

The principle of the present invention is: at present, portland cement is usually used as the cementitious material to prepare cement-based engineering materials, but the heat of hydration of portland cement is large, and the shrinkage is also large, so the ECC prepared by using it as the glue shrinks. Large deformation, not suitable for repair materials. Although sulphoaluminate cement has the characteristics of early strength and hydration product calcium vanadium stone expansion compensation shrinkage, but the later strength growth is small, it is not suitable for the preparation of cement-based engineering materials as an adhesive alone. Silica fume as a mineral admixture has strong pozzolanic activity and micro-aggregate filling effect, can improve the microstructure of the gelled slurry after hardening, and significantly improve the mechanical properties and durability. Therefore, combined with the characteristics of early strength, antifreeze, good impermeability, and micro-expansion of sulphoaluminate cement and the later high-strength characteristics of Portland cement, Portland cement, sulphoaluminate cement and silica fume are used for gelling. materials, so as to realize the superposition and complementarity in performance. The reaction equation of the gelling material is as follows:

C ₂ S+2H=CSH(gel)+CH (1-2)

C ₃ A+CH+12H＝C ₄ A·H ₁₃ (1-3)

C ₃ S+3H=CSH(gel)+2CH (1-4)

AH ₃ (gel)+3CH+3CSH ₂ ＝C ₃ A·3CSH ₃₂ (1-5)

SiO ₂ +CH=CSH (1-6)

And by compounding retarding early strength components, using ultra-dispersed viscosity-reducing high-efficiency water reducer to adjust and improve the working performance and early mechanical properties of cement-based engineering materials, mixing low elastic modulus steel fibers and high elastic modulus polyvinyl alcohol fibers to play To enhance the effect of toughening and shrinkage reduction, design and prepare cement-based engineering materials with early strength, low shrinkage and high toughness.

The early-strength, low-shrinkage and high-toughness cement-based engineering material of the present invention utilizes the micro-expansion characteristics of the hydration product of sulphoaluminate cement, replaces part of the ordinary Portland cement, and is mixed with active mineral component silica fume, compounded with retarded early-strength components It is prepared by using ultra-dispersed viscosity-reducing high-efficiency water-reducing agent, mixed steel fiber and polyvinyl alcohol fiber. The prepared cement-based engineering material has good working performance, high early strength, large later strength growth, excellent mechanical properties, volume stability, and high toughness. The invention significantly improves the shortcomings of the cement-based engineering material, such as large shrinkage, easy debonding and cracking of the repair layer and the base layer, high viscosity, difficulty in construction, and high cost, and has important practical application significance.

Compared with prior art, the beneficial effect of the present invention is:

(1) Use sulphoaluminate cement to replace part of Portland cement, give full play to the superimposed and complementary advantages of the two properties, use the characteristics of early strength and micro-expansion of calcium vanadium stone, the hydration product of sulphoaluminate cement, and adjust the setting through compounding The components realize the early strength and low shrinkage properties of cement-based engineering materials, enhance the durability of interface bonding, and can be used in the field of rapid repair, broadening the application range of cement-based engineering materials;

(2) Use cheap low-elastic-modulus steel fibers to replace some expensive high-elastic-modulus polyvinyl alcohol fibers, which not only exerts the performance effect and size effect of hybrid fibers, comprehensively improves the effect of strengthening, toughening and shrinkage reduction, but also significantly reduces raw materials. cost;

(3) The preparation process is simple, and the cost is reduced by using fine river sand instead of quartz sand; the ultra-dispersed viscosity-reducing high-efficiency water reducer is used to disperse cement particles, reduce the cohesion of the slurry, and the prepared cement-based engineering materials have good working performance , high early strength, and has good mechanical properties and durability. It is applied in the rapid repair of bridge decks, which can realize rapid repair and rapid traffic opening.

Detailed ways

In order to better understand the present invention, the content of the present invention is further illustrated below in conjunction with the examples, but the content of the present invention is not limited to the following examples.

In the following examples: the sulphoaluminate cement is R.SAC42.5 sulphoaluminate cement, specific surface area ≥ 400m ² /kg, 0.08mm sieve residue ≤ 10.0%, 0.2% ≤ 28d free expansion rate ≤ 0.4%. The ordinary Portland cement (ie Portland cement) is PO42.5 Portland cement with a specific surface area ≥ 300m ² /kg. The silica fume is micro silica fume, the specific surface area is ≥20000m ² /kg, and the activity index is ≥90%. The steel fibers are copper-plated short-wire steel fibers with a diameter of 0.2mm and a length of 10mm, a tensile strength of ≥1800MPa, and an elastic modulus of ≥200MPa. The polyvinyl alcohol fiber has a length of 12 mm, an aspect ratio of 316, a breaking strength of ≥1600 MPa, and an elastic modulus of ≥28 GPa. The water reducer is an ultra-dispersed viscosity-reducing polycarboxylic acid-based high-efficiency water reducer. The early strength agent is lithium carbonate, industrial grade, with a content ≥ 98% (by mass). The retarder is boric acid, industrial grade, with a content ≥ 98% (by mass). The mud content of the river sand is 0% (mass), the particle size is not greater than 1.18mm, the fineness modulus is ≤1.7, and the apparent density is ≤2700kg/m ³ .

Example 1:

A cement-based engineering material with early strength, low shrinkage and high toughness. The weight ratio (kg/m ³ ) of each raw material is: water 210, sulfoaluminate cement 480, ordinary Portland cement 60, silica fume 60, steel fiber 50, polyvinyl alcohol fiber 10, water reducing agent 7.2, early strength agent 0.21, retarder 1.8, river sand 1200.

The above-mentioned preparation method of an early-strength low-shrinkage high-toughness cement-based engineering material comprises the following steps:

1) Take raw materials according to the above raw material ratio;

2) Take part of the water and heat it into warm water (the temperature of the warm water is 45-60° C.), respectively dissolving the early strength agent (lithium carbonate) and the retarder (boric acid) in warm water to obtain a lithium carbonate solution and a boric acid solution;

3) Mix sulphoaluminate cement, ordinary Portland cement, silica fume and river sand dry-mixed for 1 minute to obtain a mixture; add the remaining water to the obtained mixture (that is, deduct the water for dissolving lithium carbonate and boric acid) , water reducer, stirring for 2-3min to prepare a mixed slurry;

4) Add the steel fiber and polyvinyl alcohol fiber evenly into the mixed slurry respectively, and stir for 3 minutes until the mixed fiber is evenly dispersed in the mixed slurry to obtain a fiber-containing mixed slurry;

5) adding the lithium carbonate solution and the boric acid solution into the fiber-containing mixed slurry obtained in step 4), and stirring for 1 min;

6) Pour the slurry obtained in 5) into a mold to form it, smooth it, cover it with a film, let it stand for 4 to 5 hours, demould it, and perform curing to obtain a cement-based engineering material with early strength, low shrinkage and high toughness.

See Table 1 for the mix ratio of the early-strength, low-shrinkage, high-toughness cement-based engineering material prepared in this example, and see Tables 2 and 3 for the working performance, mechanical properties and durability parameters.

Example 2:

A cement-based engineering material with early strength, low shrinkage and high toughness. The weight ratio (kg/m ³ ) of each raw material is: water 220, sulfoaluminate cement 470, ordinary Portland cement 70, silica fume 60, steel fiber 60, polyvinyl alcohol fiber 8, water reducing agent 7, early strength agent 0.2, retarder 1.7, river sand 1200.

The above-mentioned preparation method of an early-strength low-shrinkage high-toughness cement-based engineering material comprises the following steps:

1) Take raw materials according to the above raw material ratio;

2) Take part of the water and heat it into warm water (the temperature of the warm water is 45-60° C.), respectively dissolving the early strength agent (lithium carbonate) and the retarder (boric acid) in warm water to obtain a lithium carbonate solution and a boric acid solution;

3) Mix sulphoaluminate cement, ordinary Portland cement, silica fume and river sand dry-mixed for 1 minute to obtain a mixture; add the remaining water to the obtained mixture (that is, deduct the water for dissolving lithium carbonate and boric acid) , water reducer, stirring for 2-3min to prepare a mixed slurry;

4) Add the steel fiber and polyvinyl alcohol fiber evenly into the mixed slurry respectively, and stir for 3 minutes until the mixed fiber is evenly dispersed in the mixed slurry to obtain a fiber-containing mixed slurry;

5) adding the lithium carbonate solution and the boric acid solution into the fiber-containing mixed slurry obtained in step 4), and stirring for 1 min;

6) Pour the slurry obtained in 5) into a mold to form it, smooth it, cover it with a film, let it stand for 4 to 5 hours, demould it, and perform curing to obtain a cement-based engineering material with early strength, low shrinkage and high toughness.

See Table 1 for the mix ratio of the early-strength, low-shrinkage, high-toughness cement-based engineering material prepared in this example, and see Tables 2 and 3 for the working performance, mechanical properties and durability parameters.

Example 3:

A cement-based engineering material with early strength, low shrinkage and high toughness. The weight ratio (kg/m ³ ) of each raw material is: water 200, sulfoaluminate cement 490, ordinary Portland cement 60, silica fume 50, steel fiber 50, polyvinyl alcohol fiber 9, water reducing agent 7.1, early strength agent 0.22, retarder 1.8, river sand 1210.

The above-mentioned preparation method of an early-strength low-shrinkage high-toughness cement-based engineering material comprises the following steps:

1) Take raw materials according to the above raw material ratio;

2) Take part of the water and heat it into warm water (the temperature of the warm water is 45-60° C.), respectively dissolving the early strength agent (lithium carbonate) and the retarder (boric acid) in warm water to obtain a lithium carbonate solution and a boric acid solution;

3) Mix sulphoaluminate cement, ordinary Portland cement, silica fume and river sand dry-mixed for 1 minute to obtain a mixture; add the remaining water to the obtained mixture (that is, deduct the water for dissolving lithium carbonate and boric acid) , water reducer, stirring for 2-3min to prepare a mixed slurry;

4) Add the steel fiber and polyvinyl alcohol fiber evenly into the mixed slurry respectively, and stir for 3 minutes until the mixed fiber is evenly dispersed in the mixed slurry to obtain a fiber-containing mixed slurry;

5) adding the lithium carbonate solution and the boric acid solution into the fiber-containing mixed slurry obtained in step 4), and stirring for 1 min;

6) Pour the slurry obtained in 5) into a mold to form it, smooth it, cover it with a film, let it stand for 4 to 5 hours, demould it, and perform curing to obtain a cement-based engineering material with early strength, low shrinkage and high toughness.

See Table 1 for the mix ratio of the early-strength, low-shrinkage, high-toughness cement-based engineering material prepared in this example, and see Tables 2 and 3 for the working performance, mechanical properties and durability parameters.

Example 4:

A cement-based engineering material with early strength, low shrinkage and high toughness. The weight ratio (kg/m ³ ) of each raw material is: water 200, sulfoaluminate cement 460, ordinary Portland cement 50, silica fume 70, steel fiber 50, polyvinyl alcohol fiber 8, water reducing agent 7.1, early strength agent 0.22, retarder 1.8, river sand 1220.

The above-mentioned preparation method of an early-strength low-shrinkage high-toughness cement-based engineering material comprises the following steps:

1) Take raw materials according to the above raw material ratio;

2) Take part of the water and heat it into warm water (the temperature of the warm water is 45-60° C.), respectively dissolving the early strength agent (lithium carbonate) and the retarder (boric acid) in warm water to obtain a lithium carbonate solution and a boric acid solution;

3) Mix sulphoaluminate cement, ordinary Portland cement, silica fume and river sand dry-mixed for 1 minute to obtain a mixture; add the remaining water to the obtained mixture (that is, deduct the water for dissolving lithium carbonate and boric acid) , water reducer, stirring for 2-3min to prepare a mixed slurry;

4) Add the steel fiber and polyvinyl alcohol fiber evenly into the mixed slurry respectively, and stir for 3 minutes until the mixed fiber is evenly dispersed in the mixed slurry to obtain a fiber-containing mixed slurry;

5) adding the lithium carbonate solution and the boric acid solution into the fiber-containing mixed slurry obtained in step 4), and stirring for 1 min;

6) Pour the slurry obtained in 5) into a mold to form it, smooth it, cover it with a film, let it stand for 4 to 5 hours, demould it, and perform curing to obtain a cement-based engineering material with early strength, low shrinkage and high toughness.

See Table 1 for the mix ratio of the early-strength, low-shrinkage, high-toughness cement-based engineering material prepared in this example, and see Tables 2 and 3 for the working performance, mechanical properties and durability parameters.

Example 5:

A cement-based engineering material with early strength, low shrinkage and high toughness. The weight ratio (kg/m ³ ) of each raw material is: water 220, sulfoaluminate cement 480, ordinary Portland cement 60, silica fume 70, steel fiber 50, polyvinyl alcohol fiber 8, water reducing agent 7, early strength agent 0.21, retarder 1.9, river sand 1180.

The above-mentioned preparation method of an early-strength low-shrinkage high-toughness cement-based engineering material comprises the following steps:

1) Take raw materials according to the above raw material ratio;

2) Take part of the water and heat it into warm water (the temperature of the warm water is 45-60° C.), respectively dissolving the early strength agent (lithium carbonate) and the retarder (boric acid) in warm water to obtain a lithium carbonate solution and a boric acid solution;

3) Mix sulphoaluminate cement, ordinary Portland cement, silica fume and river sand dry-mixed for 1 minute to obtain a mixture; add the remaining water to the obtained mixture (that is, deduct the water for dissolving lithium carbonate and boric acid) , water reducer, stirring for 2-3min to prepare a mixed slurry;

4) Add the steel fiber and polyvinyl alcohol fiber evenly into the mixed slurry respectively, and stir for 3 minutes until the mixed fiber is evenly dispersed in the mixed slurry to obtain a fiber-containing mixed slurry;

5) adding the lithium carbonate solution and the boric acid solution into the fiber-containing mixed slurry obtained in step 4), and stirring for 1 min;

6) Pour the slurry obtained in 5) into a mold to form it, smooth it, cover it with a film, let it stand for 4 to 5 hours, demould it, and perform curing to obtain a cement-based engineering material with early strength, low shrinkage and high toughness.

See Table 1 for the mix ratio of the early-strength, low-shrinkage, high-toughness cement-based engineering material prepared in this example, and see Tables 2 and 3 for the working performance, mechanical properties and durability parameters.

Comparative Example 6

An ordinary cement-based engineering material, the weight ratio of each component (kg/m ³ ) is: water 370, ordinary portland cement 900, fly ash 100, quartz sand 900, ordinary water reducing agent 10, polyethylene Alcohol fiber26.

The preparation method of the common cement-based engineering material comprises: weighing raw materials according to the above-mentioned raw material ratio, mixing cement, fly ash and polyvinyl alcohol fiber for 1 min, so that the cementitious material and polyvinyl alcohol fiber are fully mixed evenly, Then add water and water reducer and stir for 4 minutes to fully stir the slurry, pour the mixed slurry into a mold to form, smooth it, cover it with a film, let it stand for 24 hours, demould, and perform maintenance to obtain the ordinary cement-based project. Material.

See Table 1 for the mix ratio of the common cement-based engineering materials described in this example, and see Table 2 and Table 3 for the parameters of workability, mechanical properties and durability.

Table 1 shows the mixing ratios of the early-strength, low-shrinkage, high-toughness cement-based engineering materials prepared in Examples 1-5 and the ordinary cement-based engineering materials prepared in Example 6.

Table 1 Example 1-6 Cement-based engineering material mix ratio (kg/m ³ )

The working performance and mechanical properties of the early strength, low shrinkage and high toughness cement-based engineering materials prepared in Examples 1-5 and the ordinary cement-based engineering materials prepared in Example 6 were tested, and the results are shown in Table 2.

The working performance and mechanical property parameters of the cement-based engineering material that table 2 embodiment 1～6 makes

Table 2 illustrates: Compared with ordinary cement-based engineering materials, the early-strength, low-shrinkage, high-toughness cement-based engineering materials prepared by the present invention have good work performance and high early strength, which shows that the super-dispersed viscosity-reducing high-efficiency water reducer and steel fiber are used to replace parts Under the joint action of polyvinyl alcohol fiber, the viscosity of cement-based engineering material slurry can be effectively reduced, and the working performance of cement-based engineering materials can be improved; it also shows that the combination of retarder and early strength agent can effectively adjust the cement-based engineering material. The setting time of the material can ensure a high early strength, which meets the requirements of rapid hardening and early strength of the rapid repair material.

Compared with common cement-based engineering materials, the early-strength, low-shrinkage and high-toughness cement-based engineering materials prepared by the invention have better mechanical properties in later stages and comparable bending toughness. It shows that the mixing of steel fiber with low elastic modulus and polyvinyl alcohol fiber with high elastic modulus can complement each other, and the performance effect and size effect of the two can be fully exerted in the mortar, and the toughening and strengthening effects can be comprehensively improved.

The volume stability and durability of the early-strength, low-shrinkage, high-toughness cement-based engineering materials prepared in Examples 1-5 and the ordinary cement-based engineering materials prepared in Example 6 were tested, and the unilateral cost was calculated. The results are shown in Table 3.

The volume stability performance, durability performance and cost parameter of the cement-based engineering material that table 3 embodiment 1～6 makes

Table 3 illustrates: compared with ordinary cement-based engineering materials, the early-strength, low-shrinkage and high-toughness cement-based engineering materials prepared by the present invention have good durability; the drying shrinkage deformation is small, which is 1/9 of ordinary cement-based engineering materials. It shows that using sulfoaluminate cement compounded with Portland cement and silica fume as cementitious material can significantly improve the volume stability of cement-based engineering materials; the unilateral cost is low, saving 60% of raw material costs, and the economic benefits are obvious. Good practical application value.

Detect the working performance, mechanical properties and durability parameters of the early-strength, low-shrinkage, high-toughness cement-based engineering materials prepared in Examples 1 to 5, and the results show that the early-strength, low-shrinkage, high-toughness cement-based engineering materials prepared by the present invention have good mechanical properties. High performance, volume stability and durability, with great practical application value.

The upper and lower limits and interval values of each raw material and process parameter involved in the present invention can realize the present invention, and the examples are not listed one by one here.

Claims (5)

1. A cement-based engineering material with early strength, low shrinkage and high toughness, characterized in that it consists of sulphoaluminate cement, ordinary Portland cement, silica fume, steel fiber, polyvinyl alcohol fiber, water, water reducing agent, It is prepared from early strength agent, retarder and river sand raw materials. The content of each raw material is: sulphoaluminate cement 460~500kg/m ³ , ordinary portland cement 50~70kg/m ³ , silica fume 50~70kg /m ³ , steel fiber 40~60kg/m ³ , polyvinyl alcohol fiber 8~10kg/m ³ , water 200~220kg/m ³ , water reducing agent 7.0~7.4kg/m ³ , early strength agent 0.2~0.22kg /m ³ , retarder 1.7～1.9kg/m ³ , river sand 1180～1220kg/m ³ ; The sulphoaluminate cement is R.SAC42.5 sulphoaluminate cement, with specific surface area ≥ 400m ² /kg, 0.08mm sieve residue ≤ 10.0%, 0.2% ≤ 28d free expansion rate ≤ 0.4%; The ordinary Portland cement is PO42.5 Portland cement with a specific surface area ≥ 300m ² /kg; The silica fume is micro silica fume, the specific surface area is ≥20000m ² /kg, and the activity index is ≥90%; The steel fibers are copper-plated short steel fibers with a diameter of 0.2 mm, a length of 10 mm, a tensile strength ≥ 1800 MPa, and a modulus of elasticity ≥ 200 MPa; The polyvinyl alcohol fiber has a length of 12 mm, an aspect ratio of 316, a breaking strength of ≥1600 MPa, and an elastic modulus of ≥28 GPa. 2. The early-strength, low-shrinkage, high-toughness cement-based engineering material according to claim 1, wherein the water reducer is an ultra-dispersed viscosity-reducing polycarboxylic acid-based high-efficiency water reducer. 3. a kind of early-strength low-shrinkage high-toughness cement-based engineering material according to claim 1, is characterized in that, described early-strength agent is lithium carbonate, industrial grade, and content >=98% (mass). 4. A kind of early-strength low-shrinkage high-toughness cement-based engineering material according to claim 1, is characterized in that, described retarder is boric acid, industrial grade, content >=98% (mass); Described river sand contains The amount of mud is 0% (mass), the particle size is not greater than 1.18mm, the fineness modulus is ≤1.7, and the apparent density is ≤2700kg/m ³ . 5. the preparation method of a kind of early-strength low-shrinkage high-toughness cement-based engineering material according to claim 1, is characterized in that comprising the following steps: 1) According to the content of each raw material: sulphoaluminate cement 460~500kg/m ³ , ordinary Portland cement 50~70kg/m ³ , silica fume 50~70kg/m ³ , steel fiber 40~60kg/m ³ , polyvinyl alcohol fiber 8~10kg/m ³ , water 200~220kg/m ³ , water reducer 7.0~7.4kg/m ³ , early strength agent 0.2~0.22kg/m ³ , retarder 1.7~1.9kg/m 3 m ³ , river sand 1180～1220kg/m ³ , weigh raw materials; 2) Take part of the water and heat it into warm water, and dissolve the early strength agent and the retarder in warm water respectively to obtain a lithium carbonate solution and a boric acid solution; 3) Dry mixing sulphoaluminate cement, ordinary Portland cement, silica fume and river sand to obtain a mixture; add the remaining water and water reducer to the obtained mixture, and stir to obtain a mixed slurry ; 4) uniformly adding steel fibers and polyvinyl alcohol fibers into the mixed slurry respectively, and stirring to obtain a mixed slurry containing fibers; 5) Lithium carbonate solution and boric acid solution are added in step 4) the obtained fiber-containing mixed slurry, stirring; 6) Pour the slurry obtained in 5) into a mold to form it, let it stand for 4 to 5 hours, demould it, and perform curing to obtain a cement-based engineering material with early strength, low shrinkage and high toughness.