CN110698145A - Trapezoidal sleeper square steel micro-expansion concrete - Google Patents

Abstract

The invention belongs to the technical field of concrete, and particularly relates to trapezoidal sleeper square steel micro-expansion concrete. The concrete comprises the following raw materials: cement, fly ash, coarse-grain quartz sand, medium-coarse-grain quartz sand, fine-grain quartz sand, No. 0 colloidal crystal and an expanding agent. The micro-expansion concrete has good linear expansion rate, and a formed casting body is free from shrinkage after long-term use, so that equipment can be ensured to be in close contact with a foundation.

Description

Trapezoidal sleeper square steel micro-expansion concrete

Technical Field

The invention belongs to the technical field of concrete, and particularly relates to trapezoidal sleeper square steel micro-expansion concrete.

Background

Along with the rapid development of national economy, the life quality of people is remarkably improved, the requirements for buildings are continuously changed, the appearance condition and the use function of the buildings are concerned more, and the slightly-expanded concrete plays an important role in the field of buildings from new construction to reinforcement and reconstruction.

The slightly expansive concrete is prepared by using cement-base, slightly expansive, early strength and high strength concrete, using high strength material as aggregate, using cement as binding agent and using high flow state, slightly expansive and segregation-resisting substances, and features good fluidity, slightly expansive, early strength and high strength, resisting oil leakage, etc., and can fully fill the pouring space, and a certain quantity of water can be added in the construction site, and after uniformly stirred, it can be used.

When trapezoidal pillow preparation, the intermediate junction is the square steel, generally will pack the concrete in the square steel, improves the intensity of square steel, and the concrete that current square steel was filled is ordinary concrete, has following defect after ordinary concrete and the square steel combination: long solidification period, low strength, linear expansion which can not meet the requirement, low strength and the like. How to provide the properties of square steel is the direction of research in the technical field at present.

Disclosure of Invention

In view of the above, the present invention provides a trapezoidal sleeper square steel micro-expansion concrete, a method for preparing the trapezoidal sleeper square steel micro-expansion concrete, and a method for grouting and constructing a square steel by using the micro-expansion concrete.

The technical scheme adopted by the invention is as follows:

the trapezoidal sleeper square steel micro-expansion concrete comprises the following raw materials in parts by weight: 340 parts of cement, 230 parts of fly ash 210, 40-50 parts of large-particle-size quartz sand, 180 parts of medium-large-particle-size quartz sand, 220 parts of small-particle-size quartz sand, 15-20 parts of 0# colloidal crystal and an expanding agent.

The particle size of the coarse-particle-size quartz sand is 6-8 meshes, the particle size of the medium-coarse-particle-size quartz sand is 10-20 meshes, and the particle size of the fine-particle-size quartz sand is 20-40 meshes.

The fly ash is I-grade fly ash.

The cement is 42.5 Portland cement;

the dosage of the expanding agent is 0.002 percent of the total amount of other raw materials except the expanding agent.

The method for preparing the trapezoidal sleeper square steel micro-expansion concrete comprises the following steps: 1) taking the raw materials according to the proportion;

2) mixing the quartz sand with the grain sizes of coarse, medium and fine, then sequentially feeding the mixed quartz sand, cement, fly ash, 0# colloidal crystal and expanding agent, and stirring for 4min to mix uniformly.

The method for grouting square steel by utilizing micro-expansion concrete comprises the following steps: 1) the square steel which is qualified in acceptance is vertically fixed;

2) the steel bar penetrates through the square steel along the direction perpendicular to the square steel, so that the sealing performance of a perforated part between the steel bar and the square steel is guaranteed (a sealing ring is arranged at the perforated part between the steel bar and the square steel); the specification of the twisted steel bar is 525mm long and phi 20, the lengths of the square steel parts exposed at the two ends of the steel bar are the same, and the error is controlled within 20 mm;

3) then taking the micro-expansive concrete of claim 1, adding water and stirring to form concrete slurry, wherein the water consumption is 12-14%; the optimal water consumption is 13.5%;

4) pouring the mixture into square steel twice, hammering the outer wall of the square steel during first pouring to discharge gas in the pouring material and compact the material, then pouring for the second time, and hammering the outer wall of the square steel during second pouring;

5) and after grouting, removing the mold, and then performing moisture preservation and maintenance.

When the construction environment temperature is higher than 30 ℃, cooling treatment is carried out before grouting, so that the construction part is prevented from being directly irradiated by sunlight or other heat radiation, the temperature of the square steel is lower than 30 ℃, the mold-entering temperature of the concrete slurry is lower than 30 ℃, and immediately curing is carried out after grouting;

when the construction environment temperature is lower than 0 ℃, the water temperature of the micro-expansive concrete when water is added is 30-35 ℃.

The concrete slurry is used within 30min from the water addition.

The mould removing time and the maintenance time of the square steel are as follows:

when the environment temperature is-10-0 ℃, the mold removal time is 96h, and the maintenance time is 14 h;

when the environmental temperature is 0-5 ℃, the mold stripping time is 72h, and the maintenance time is 10 h;

when the environment temperature is 5-15 ℃, the mold stripping time is 48h, and the maintenance time is 7 h;

when the environmental temperature is more than or equal to 15 ℃, the mold removal time is 24 hours, and the maintenance time is 7 hours.

If the environmental temperature is lower than the lowest construction temperature required by the product or the strength increase needs to be accelerated, the steam curing mode can be adopted.

After grouting, covering a layer of plastic film on each working surface, covering the plastic film with industrial felt cloth, paving the electric mattress on the felt cloth, pressing the cotton quilt on the electric mattress for heat preservation, and arranging people to measure the temperature in a workshop and the temperature of the bedding on the working surface at any time, thereby ensuring the construction temperature and reaching the standard maintenance temperature.

Compared with the prior art, the invention has the following beneficial technical effects:

1. according to the invention, the fineness and activity of the raw materials are selected to reduce the defects of gaps and microcracks in the materials, so that high strength and high durability are obtained;

2. according to the invention, the raw material selection is adopted to remove coarse aggregate so as to improve the mechanical property of cement mortar, eliminate the interface transition between the aggregate and the cement mortar and improve the uniformity of a matrix, thereby improving various properties of the micro-expansive concrete;

3. the invention selects the admixture with good compatibility with the active component, improves the strength of the cement mortar, reduces the water consumption and greatly reduces the porosity;

4. the fly ash is added into the components, so that the waste utilization is realized, and the durability of the concrete is improved;

5. the strength of the micro-expansion concrete reaches up to 30MPa after 1-3 days, and the construction period can be shortened; during construction, only water is added and stirred on site, the mortar is directly poured into the equipment, the mortar flows automatically, vibration is avoided during construction, and vibration-free and long-distance grouting construction can be ensured;

6. the micro-expansion concrete has good linear expansion rate, and a formed pouring body has no shrinkage after long-term use, so that equipment can be ensured to be in close contact with a foundation, no shrinkage exists between the equipment and the foundation, and the requirement of secondary grouting of the equipment is met;

7. the water consumption during the construction of the micro-expansion concrete is controlled, so that the concrete can have good slump and slump expansion;

8. according to the invention, the selected quartz sand has three particle sizes of coarse, medium and fine, the usage amount of the quartz sand with the three particle sizes is strictly controlled, the usage amount of the quartz sand with the coarse particle size is strictly controlled, the slump and the expansion degree are prevented from being influenced by overlarge usage amount, the usage amount of the quartz sand with the medium particle size and the quartz sand with the fine particle size is also required to be controlled, the strength of concrete is prevented from being influenced by overlarge usage amount, and the usage amounts of the quartz sand with the three particle sizes and the quartz sand with the coarse, medium and fine particle sizes are the optimal formula on the basis of actual test data through long-term large-scale test comparison.

Drawings

FIG. 1 is a schematic structural view of a square steel mounting bar;

fig. 2 is a schematic structural view of a longitudinal section of a reinforcing steel bar passing through a square steel part.

Detailed Description

The following examples are given to illustrate specific embodiments of the present invention, but are not intended to limit the scope of the present invention in any way.

The cement used in the following examples is 42.5 portland cement, the fly ash is class i fly ash, the particle size of the large-particle-size quartz sand is 6-8 mesh, the particle size of the medium-particle-size quartz sand is 10-20 mesh, and the particle size of the fine-particle-size quartz sand is 20-40 mesh.

Example 1:

the trapezoidal sleeper square steel micro-expansion concrete comprises the following raw materials in parts by weight: 330kg of cement, 220kg of fly ash, 43kg of coarse-grain-size quartz sand, 172kg of medium-coarse-grain-size quartz sand, 215 kg of fine-grain-size quartz sand, 20kg of 0# colloidal crystal and 0.2kg of expanding agent.

Example 2:

the trapezoidal sleeper square steel micro-expansion concrete comprises the following raw materials in parts by weight: 320kg of cement, 230 kg of fly ash, 40 kg of coarse-grain quartz sand, 180 kg of medium-coarse-grain quartz sand, 210kg of fine-grain quartz sand, 20kg of 0# colloidal crystal and 0.2kg of expanding agent.

Example 3:

the trapezoidal sleeper square steel micro-expansion concrete comprises the following raw materials in parts by weight: 335kg of cement, 210kg of fly ash, 50 kg of coarse-grain quartz sand, 170kg of medium-coarse-grain quartz sand, 220kg of fine-grain quartz sand, 15kg of 0# colloidal crystal and 0.2kg of expanding agent.

Example 4:

the trapezoidal sleeper square steel micro-expansion concrete comprises the following raw materials in parts by weight: 335kg of cement, 230 kg of fly ash, 50 kg of coarse-grain quartz sand, 180 kg of medium-coarse-grain quartz sand, 210kg of fine-grain quartz sand, 15kg of 0# colloidal crystal and 0.204kg of expanding agent.

Example 5:

the method for preparing the trapezoidal sleeper square steel micro-expansion concrete of the embodiment 1 to 4 comprises the following steps: 1) taking the raw materials according to the proportion;

2) mixing the quartz sand with the grain sizes of coarse, medium and fine, then sequentially feeding the mixed quartz sand, cement, fly ash, 0# colloidal crystal and expanding agent, and stirring for 4min to mix uniformly.

Example 6: the method for grouting square steel by utilizing micro-expansion concrete comprises the following steps:

1) the square steel which is qualified in acceptance is vertically fixed;

2) the reinforcing steel bar 3 penetrates through the square steel along the direction perpendicular to the square steel 1 (as shown in figure 1), and in order to ensure the sealing performance of a perforated part between the reinforcing steel bar 3 and the square steel 1, a sealing ring 2 is arranged at the perforated part between the reinforcing steel bar 3 and the square steel 1 (as shown in figure 2); the specification of the twisted steel bar is 525mm long and phi 20, the lengths of the square steel parts exposed at the two ends of the steel bar are the same, and the error is controlled within 20 mm;

3) then taking the micro-expansion concrete prepared in any one of the embodiments 1-3, adding water and stirring to obtain concrete slurry, wherein the water consumption is 12-14%; the optimal water consumption is 13.5%;

4) pouring the mixture into square steel twice, hammering the outer wall of the square steel during first pouring to discharge gas in the poured material, compacting the material, then pouring for the second time, hammering the outer wall of the square steel during second pouring, and finishing the use of the concrete slurry within 30min from the time of adding water;

5) after grouting, removing the formwork, processing and leveling the concrete at the two ends of the square steel, and performing moisture preservation and maintenance;

when the moisture-keeping maintenance is carried out, a layer of plastic film is firstly covered on each layer of operation surface, then the plastic film is covered on the operation surface, then the industrial felt cloth is covered on the plastic film, then the electric mattress is paved on the felt cloth, the cotton quilt is pressed on the electric mattress for heat preservation, and a person is arranged to measure the temperature in a workshop and the temperature of the bedding on the operation surface at any time, so that the construction temperature is ensured, and the standard maintenance temperature is reached.

The following technical requirements are specifically met in the construction process:

when the construction environment temperature is higher than 30 ℃, cooling treatment is carried out before grouting, so that the construction part is prevented from being directly irradiated by sunlight or other heat radiation, the temperature of the square steel is lower than 30 ℃, the mold-entering temperature of the concrete slurry is lower than 30 ℃, and immediately curing is carried out after grouting;

when the construction environment temperature is lower than 0 ℃, the water temperature of the micro-expansive concrete when water is added is 30-35 ℃.

The mould removing time and the maintenance time of the square steel are as follows:

when the environment temperature is-10-0 ℃, the square steel is demolded for 96 hours, and the maintenance time is 14 hours;

when the environmental temperature is 0-5 ℃, the square steel is demolded for 72 hours, and the maintenance time is 10 hours;

when the environmental temperature is 5-15 ℃, the square steel is demolded for 48 hours, and the maintenance time is 7 hours;

and when the environmental temperature is more than or equal to 15 ℃, the square steel stripping time is 24 hours, and the maintenance time is 7 hours.

If the environmental temperature is lower than the lowest construction temperature required by the product or the strength increase needs to be accelerated, the steam curing mode can be adopted.

Concrete requirements in grouting: (1) the grouting material poured into the steel pipe is tightly pressed, no air hole is formed, and the hollow phenomenon is avoided;

(2) the weight standard of the steel pipe (containing the steel bar) after grouting is 67 plus or minus 1 kg;

(3) after filling, cement at two ends of the steel pipe is smooth, so that the defects of leakage filling, air holes, protrusion and the like are avoided, and the outer surface of the steel pipe is free from sagging and adhesion of grouting material;

(4) the grouting process is continuously carried out without interruption, the grouting time is shortened as far as possible, and the vibrator cannot be used for vibrating in the grouting process.

Comparative example 1:

the concrete comprises the following raw materials in parts by weight: 330kg of cement, 220kg of fly ash, 90kg of coarse-grain-size quartz sand, 125kg of medium-coarse-grain-size quartz sand, 215 kg of fine-grain-size quartz sand, 20kg of 0# colloidal crystal and 0.2kg of expanding agent.

Comparative example 2:

the concrete comprises the following raw materials in parts by weight: 330kg of cement, 220kg of fly ash, 20kg of coarse-grain-size quartz sand, 195kg of medium-coarse-grain-size quartz sand, 215 kg of fine-grain-size quartz sand, 20kg of 0# colloidal crystal and 0.2kg of expanding agent.

Comparative example 3:

the concrete comprises the following raw materials in parts by weight: 330kg of cement, 220kg of fly ash, 43kg of coarse-grain-size quartz sand, 220kg of medium-coarse-grain-size quartz sand, 167kg of fine-grain-size quartz sand, 20kg of 0# colloidal crystal and 0.2kg of expanding agent.

Comparative example 4:

the concrete comprises the following raw materials in parts by weight: 330kg of cement, 220kg of fly ash, 83kg of coarse-grain-size quartz sand, 172kg of medium-coarse-grain-size quartz sand, 175kg of fine-grain-size quartz sand, 20kg of No. 0 colloidal crystal and 0.2kg of expanding agent.

The trapezoidal sleeper steel micro-expansion concrete prepared in the examples 1 to 4 and the concrete prepared in the comparative examples 1 to 4 were prepared according to the method of example 5, and the finally prepared concrete was tested according to the national standard method, and the test results are shown in the following table:

the method of the above-mentioned inspection basis is: GB/T50448-.

As shown in the above table, the performance indexes of the slightly-expanded concrete prepared in examples 1 to 4 all reach ideal states, but when the amount of the coarse-grain quartz sand is large and the amount of the medium-grain quartz sand is small in comparative example 1, the slump and the expansion degree do not meet the technical requirements.

When the comparative example 2 has a small amount of the coarse-particle-size quartz sand and a large amount of the medium-particle-size quartz sand, the 28-day strength cannot meet the design requirements.

In the comparative example 3, when the amount of the quartz sand with the particle size is large and the amount of the quartz sand with the fine particle size is small, the 28-day strength cannot meet the design requirement, the slump and the expansion steel meet the design requirement, and the margin is small.

In comparative example 4, when the amount of the coarse-particle-size quartz sand is large and the amount of the fine-particle-size quartz sand is small, the slump cannot meet the design requirement.

From the above experiments, it can be seen that the concrete strength, slump and expansion can be ensured to be in an ideal state only under the premise of strictly controlling the use amount of the coarse-grain-size quartz sand, the medium-grain-size quartz sand and the fine-grain-size quartz sand.

Finally, the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting, and other modifications or equivalent substitutions made by the technical solutions of the present invention by those of ordinary skill in the art should be covered within the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solutions of the present invention.

Claims (9)

1. The trapezoidal sleeper square steel micro-expansion concrete is characterized by comprising the following raw materials in parts by weight: 340 parts of cement, 230 parts of fly ash 210, 40-50 parts of large-particle-size quartz sand, 180 parts of medium-large-particle-size quartz sand, 220 parts of small-particle-size quartz sand, 15-20 parts of 0# colloidal crystal and an expanding agent.

2. The trapezoidal sleeper square steel micro-expansion concrete as claimed in claim 1, wherein:

the particle size of the coarse-particle-size quartz sand is 6-8 meshes, the particle size of the medium-coarse-particle-size quartz sand is 10-20 meshes, and the particle size of the fine-particle-size quartz sand is 20-40 meshes.

3. The trapezoidal sleeper square steel micro-expansion concrete as claimed in claim 1, wherein:

the fly ash is I-grade fly ash;

the cement is 42.5 Portland cement;

the dosage of the expanding agent is 0.002 percent of the total amount of other raw materials except the expanding agent.

4. The method for preparing the trapezoidal sleeper square steel micro-expansion concrete of claim 1, which is characterized by comprising the following steps of: 1) taking the raw materials according to the proportion;

2) mixing the quartz sand with the grain sizes of coarse, medium and fine, then sequentially feeding the mixed quartz sand, cement, fly ash, 0# colloidal crystal and expanding agent, and stirring for 4min to mix uniformly.

5. The method for grouting square steel with the micro-expansive concrete according to claim 1, comprising the steps of: 1) the square steel which is qualified in acceptance is vertically fixed;

2) the steel bar penetrates through the square steel along the direction perpendicular to the square steel, so that the sealing performance of a through hole between the steel bar and the square steel is guaranteed;

3) then taking the micro-expansive concrete of claim 1, adding water and stirring to form concrete slurry, wherein the water consumption is 12-14%;

4) pouring the mixture into square steel twice, hammering the outer wall of the square steel during first pouring to discharge gas in the pouring material and compact the material, then pouring for the second time, and hammering the outer wall of the square steel during second pouring;

5) and after grouting, removing the mold, and then performing moisture preservation and maintenance.

6. The construction method according to claim 5, wherein: when the construction environment temperature is higher than 30 ℃, cooling treatment is carried out before grouting, so that the construction part is prevented from being directly irradiated by sunlight or other heat radiation, the square steel temperature is lower than 30 ℃, the concrete slurry injection temperature is lower than 30 ℃, and the concrete slurry is maintained immediately after grouting.

7. The construction method according to claim 5, wherein: when the construction environment temperature is lower than 0 ℃, the water temperature of the micro-expansive concrete when water is added is 30-35 ℃.

8. The construction method according to claim 5, wherein: the concrete slurry is used within 30min from the water addition.

9. The construction method according to claim 5, wherein: the mould removing time and the maintenance time of the square steel are as follows:

when the environment temperature is-10-0 ℃, the mold removal time is 96h, and the maintenance time is 14 h;

when the environmental temperature is 0-5 ℃, the mold stripping time is 72h, and the maintenance time is 10 h;

when the environment temperature is 5-15 ℃, the mold stripping time is 48h, and the maintenance time is 7 h;

when the environmental temperature is more than or equal to 15 ℃, the mold removal time is 24 hours, and the maintenance time is 7 hours.

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