CN111333392A - A kind of seawater mixing coral reef sand C120UHPC and preparation method thereof - Google Patents

Abstract

The invention discloses a seawater mixing coral reef sand C120UHPC and a preparation method thereof. The UHPC composition and proportion include: ferric aluminate cement 690.2kg/m ³ ; fine coral reef powder 138.6kg/m ³ ; coarse coral reef powder 194.1kg /m ³ ; quartz sand 776.3kg/m ³ ; silica fume 138.6kg/m ³ ; fly ash 34.7kg/m ³ ; seawater 182.3kg/m ³ ; superplasticizer 41.6kg/m ³ ; steel fiber 140.4kg /m ³ ; the present invention also discloses a preparation method of the UHPC, and the maintenance method is as follows: placing the concrete test block in a standard curing room, covering the test piece with wet linen, or placing it in water, and maintaining more Secondary watering curing to prevent the evaporation of water in the concrete, this curing method avoids UHPC steam curing. The present invention has the following technical advantages: the present invention is beneficial to the application and promotion of UHPC, and is of great significance to meet the needs of large-scale engineering construction of islands and reefs in the South my country Sea, to achieve local materials, reduce costs, shorten construction periods, etc. The construction cost of the project also meets the needs of greening, energy saving and environmental protection of civil engineering.

Description

A kind of seawater mixing coral reef sand C120UHPC and preparation method thereof

technical field

The invention relates to the technical field of preparation of civil engineering materials, in particular to C120UHPC of seawater mixing coral reef sand and a preparation method thereof.

Background technique

my country's far-sea islands and reefs are far away from the mainland of the motherland, and the lack of materials and freshwater resources restricts the construction of islands.

Due to the lack of materials and fresh water resources in the construction of the far sea project, if the traditional construction materials continue to be used, not only will the task of sea transportation be arduous and the transportation cost will be too high, it will seriously restrict the large-scale construction, management and resource development of the far sea in my country. Moreover, the traditional building materials have poor durability and short service life in the marine climate environment, which seriously restricts people's large-scale construction, management and resource development in the open sea. Ultra-high performance concrete (UHPC) is a new type of cement-based composite material with the advantages of ultra-high strength, high toughness, high durability, volume stability and good impact resistance. It has good mechanical properties and durability. Also has good environmental performance.

Among these far-sea islands and reefs, the islands are mainly coral reefs, so it is necessary to consider making full use of the raw materials around the island reefs to build the island reefs. Among them, the use of coral reef sand fine aggregates instead of quartz sand to mix ultra-high performance concrete. Some marine concrete structures that do not require reinforcement, such as revetments and breakwaters, can not only get rid of the constraints of long-distance marine transportation, but also greatly save engineering costs.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a kind of coral reef cultured with seawater, which is convenient to obtain materials on site, low in cost, short in construction period, high in early strength, good in resistance to chloride ion penetration, anti-carbonization, corrosion resistance and anti-abrasion, and is more environmentally friendly and energy-saving. Powder ultra-high performance concrete and preparation method thereof.

A seawater mixing coral reef sand C120UHPC, comprising: iron aluminate cement, fine coral reef powder, coarse coral reef powder, quartz sand, silica fume, fly ash, sea water, superplasticizer, and steel fiber.

Wherein, the composition and proportion of the concrete are as follows: ferric aluminate cement 690.2kg/m ³ ; fine coral reef powder 138.6kg/m ³ ; coarse coral reef powder 194.1kg/m ³ ; quartz sand 776.3kg/m ³ ; silica fume 138.6kg/m ³ ; fly ash 34.7kg/m ³ ; seawater 182.3kg/m ³ ; superplasticizer 41.6kg/m ³ ; steel fiber 140.4kg/m ³ .

Said one kind of seawater mixing coral reef sand C120UHPC, cement is iron aluminate cement, its chemical composition is silicon dioxide (SiO ₂ ) 12.4%, alumina (Al ₂ O ₃ ) 26.45%, iron oxide (Fe _{2 )} O ₃ ) 9.50%, calcium oxide (CaO) 48.5%, sulfur trioxide (SO ₃ ) 1.46%, loss on ignition 0.15%.

The fine coral reef powder and the coarse coral reef powder are both in the original state or obtained after the broken coral reef stone is ground by a ball mill and sieved, wherein: the fine coral reef powder particle size is 1000 meshes, and the coarse coral reef powder particle size is 20-70 mesh. eye.

The quartz sand is milky white, its chemical composition silicon dioxide (SiO ₂ ) content is 99.5%-99.9%, carbon trioxide (Fe ₂ O ₃ ) content is less than 0.005%, and the particle size is 0.45-0.85mm.

。The silica fume is gray-black, and its chemical composition is silicon dioxide (SiO ₂ ) content of 94.5% to 96%, magnesium oxide (MgO) content of 0.97%, carbon trioxide (Fe ₂ O ₃ ) content of 0.83%, specific surface area 23000m ² /kg, specific gravity 2400kg/m ³ , particle size 0.05

.

。The fly ash is off-white, and its chemical composition is silicon dioxide (SiO ₂ ) content of 60.98%, aluminum oxide (Al ₂ O ₃ ) content of 24.47%, carbon trioxide (Fe ₂ O ₃ ) content of 6.7%, Calcium oxide (CaO) content is 5.1%, magnesium oxide (MgO) content is 0.68%, particle size is 8

.

The superplasticizer is a polycarboxylic acid-based superplasticizer produced by BASF (China) Co., Ltd. The superplasticizer is a liquid superplasticizer, and the steel fiber is a straight copper-plated steel fiber with a length of 12 ~14mm, diameter 0.21~0.23mm.

Said one-day compressive strength of concrete is 30Mpa, 3-day compressive strength is 58Mpa, 7-day compressive strength is 88Mpa, 28-day compressive strength is 122Mpa, and 28-day compressive strength is 122Mpa. The strength is 15.5MPa, the 28-day tensile strength is 6.98MPa, and the expansion is 211mm.

A preparation method of coral reef sand C120UHPC mixed with sea water, comprising the following steps:

Step 1: Weigh a specific amount of quartz sand, fine coral reef powder and coarse coral reef powder according to the ratio and place them in a mixer, and the mixing time is not less than 5min under low speed conditions;

Step 2: Add specific amounts of cement, silica fume and fly ash according to the ratio and place them in the mixer, and the mixing time is not less than 5min under low speed conditions;

Step 3: Weigh a specific amount of water and a high-efficiency water reducer according to the ratio, first mix and stir the two evenly, then add them to the mixer, stir at a low speed for 2 minutes, and then at a high speed for 5 minutes, until the mixture becomes fluid;

Step 4: After step 3 is completed, weigh a specific amount of steel fibers according to the ratio, slowly add them into the agitator, and continue to stir at high speed for 10min after the addition is complete;

Step 5: After step 4 is completed, slowly pour the mixed concrete into the mold, tap lightly with a small hammer 20 times on both sides of the mold, and then place it in a standard curing room for 1 day of curing;

Step 6: After the completion of Step 5, the concrete is demolded and cured, and after the curing is completed, the seawater-mixed coral reef sand C120UHPC is obtained.

The described method for preparing coral reef sand C120UHPC mixed with sea water is characterized in that: in step 6, the curing method of concrete can be as follows: 1) placing the concrete in a standard curing room, covering the test piece with wet linen, Perform high-frequency intermittent watering treatment to keep the sackcloth in a wet state; 2) Place the specimen in water for maintenance, and ensure that the temperature in the water is 20 °C.

The beneficial effects of the present invention are as follows:

1. It is convenient to use seawater and coral reef powder to mix concrete with local materials and reduce transportation costs.

2. Use seawater and ferric aluminate cement to mix UHPC, so that the early strength of concrete is high, reaching 30MPa in 1 day, so as to avoid the damage of buildings on the island due to low early strength due to high tide. UHPC is a kind of ultra-high strength and high toughness. , high durability, volume stability and good impact resistance of new cement-based composite materials, with good mechanical properties and durability, its 28-day compressive strength is 122Mpa, 28-day flexural strength is 15.5MPa, 28 The tensile strength is 6.98MPa, and it also has good environmental performance.

3. The coral reef sand has the characteristics of fast water absorption in the early stage and slow in the later stage, which leads to the internal curing and shrinkage of the coral reef to provide the durability of concrete.

4. Replace all the coral reef powders of different particle sizes with the quartz powder in the ultra-high performance concrete, partially replace the coarse aggregate quartz sand in the concrete, replace the quartz powder and reduce the amount of quartz sand, which reduces the natural resources in the environment. It can realize the purpose of energy saving and emission reduction, and reduce the area occupied by coral reef sand stacking and reduce the consumption of natural materials.

5. Based on the theory of maximum bulk density, the present invention fills the gaps between concretes by adding coral reef powders of different particle sizes, so that the concrete structure becomes more compact, thereby optimizing the bulk density of ultra-high performance concrete particles and making them each The voids between the components are fully accumulated to ensure the strength and durability of the ultra-high-performance concrete; the present invention also uses fly ash to replace part of the silica fume, and fine coral reef powder to replace 10% of the cement, thereby reducing the ultra-high-performance concrete. The production cost is economical and environmentally friendly, and the addition of fly ash can ensure the later strength of the concrete, and the surface of the fly ash microscopic particles is smooth, which can greatly improve the fluidity of the concrete, and the optimization of the water-binder ratio enables the concrete to achieve self-compacting effect. , so that it can meet different construction conditions and construction environments.

6. The seawater-cured concrete prepared by the present invention, under the action of high-efficiency water-reducing agent, continues to optimize the concrete water-to-binder ratio, so that the concrete prepared by mixing has a certain fluidity, which makes the pumping of the concrete more convenient, and the pouring Vibration is not required in the process, the gas in the slurry is discharged by the concrete due to its own weight, and the concrete achieves the effect of natural compaction; and the seawater-cured concrete prepared by the present invention does not require steam or high temperature curing, but the concrete test block is covered with wet linen cloth. , and perform high-frequency intermittent watering maintenance to ensure that the linen is in a wet state, or is placed in water for maintenance. This maintenance method not only simplifies the maintenance system, greatly reduces the maintenance cost, but also effectively prevents the evaporation of water in the concrete. During the curing period, it provides a good moisturizing environment, and its simple maintenance method and excellent curing effect make the large-scale use of seawater-mixed concrete on offshore islands and reefs with great application prospects.

Detailed ways

The present invention will be further specifically described below in conjunction with the embodiments, but not limited thereto.

A seawater mixing coral reef sand C120UHPC, comprising: iron aluminate cement, fine coral reef powder, coarse coral reef powder, quartz sand, silica fume, fly ash, sea water, superplasticizer, and steel fiber.

Wherein, the composition and proportion of the concrete are as follows: ferric aluminate cement 690.2kg/m ³ ; fine coral reef powder 138.6kg/m ³ ; coarse coral reef powder 194.1kg/m ³ ; quartz sand 776.3kg/m ³ ; silica fume 138.6kg/m ³ ; fly ash 34.7kg/m ³ ; seawater 182.3kg/m ³ ; superplasticizer 41.6kg/m ³ ; steel fiber 140.4kg/m ³ .

Said one kind of seawater mixing coral reef sand C120UHPC, cement is iron aluminate cement, its chemical composition is silicon dioxide (SiO ₂ ) 12.4%, alumina (Al ₂ O ₃ ) 26.45%, iron oxide (Fe _{2 )} O ₃ ) 9.50%, calcium oxide (CaO) 48.5%, sulfur trioxide (SO ₃ ) 1.46%, loss on ignition 0.15%.

The fine coral reef powder and the coarse coral reef powder are both in the original state or obtained after the broken coral reef stone is ground by a ball mill and sieved, wherein: the particle size of the fine coral reef powder is 1000 meshes, and the particle size of the coarse coral reef powder is 20-70 mesh. eye.

The quartz sand is milky white, its chemical composition silicon dioxide (SiO ₂ ) content is 99.5%-99.9%, carbon trioxide (Fe ₂ O ₃ ) content is less than 0.005%, and the particle size is 0.45-0.85mm.

。The silica fume is gray-black, and its chemical composition is silicon dioxide (SiO ₂ ) content of 94.5% to 96%, magnesium oxide (MgO) content of 0.97%, carbon trioxide (Fe ₂ O ₃ ) content of 0.83%, specific surface area 23000m ² /kg, specific gravity 2400kg/m ³ , particle size 0.05

.

。The fly ash is off-white, and its chemical composition is silicon dioxide (SiO ₂ ) content of 60.98%, aluminum oxide (Al ₂ O ₃ ) content of 24.47%, carbon trioxide (Fe ₂ O ₃ ) content of 6.7%, Calcium oxide (CaO) content is 5.1%, magnesium oxide (MgO) content is 0.68%, particle size is 8

.

The superplasticizer is a polycarboxylic acid-based superplasticizer produced by BASF (China) Co., Ltd. The superplasticizer is a liquid superplasticizer, and the steel fiber is a straight copper-plated steel fiber with a length of 12 ~14mm, diameter 0.21~0.23mm.

Said one-day compressive strength of concrete is 30Mpa, 3-day compressive strength is 58Mpa, 7-day compressive strength is 88Mpa, 28-day compressive strength is 122Mpa, and 28-day compressive strength is 122Mpa. The strength is 15.5MPa, the 28-day tensile strength is 6.98MPa, and the expansion is 211mm;

A preparation method of coral reef sand C120UHPC mixed with sea water, comprising the following steps:

Step 1: Weigh a specific amount of quartz sand, fine coral reef powder and coarse coral reef powder according to the ratio and place them in a mixer, and the mixing time is not less than 5min under low speed conditions;

Step 2: Add specific amounts of cement, silica fume and fly ash according to the ratio and place them in the mixer, and the mixing time is not less than 5min under low speed conditions;

Step 3: Weigh a specific amount of water and a high-efficiency water reducer according to the ratio, first mix and stir the two evenly, then add them to the mixer, stir at a low speed for 2 minutes, and then at a high speed for 5 minutes, until the mixture becomes fluid;

Step 4: After step 3 is completed, weigh a specific amount of steel fibers according to the ratio, slowly add them into the agitator, and continue to stir at high speed for 10min after the addition is complete;

Step 5: After step 4 is completed, slowly pour the mixed concrete into the mold, tap lightly with a small hammer 20 times on both sides of the mold, and then place it in a standard curing room for 1 day of curing;

Step 6: After the completion of Step 5, the concrete is demolded and cured, and after the curing is completed, the seawater-mixed coral reef sand C120UHPC is obtained.

The described method for preparing coral reef sand C120UHPC mixed with sea water is characterized in that: in step 6, the curing method of concrete can be as follows: 1) placing the concrete in a standard curing room, covering the test piece with wet linen, Perform high-frequency intermittent watering treatment to keep the sackcloth in a wet state; 2) Place the specimen in water for maintenance, and ensure that the temperature in the water is 20 °C.

Claims (10)

1. a seawater mixing coral reef sand C120UHPC, is characterized in that: comprise: iron aluminate cement, fine coral reef powder, thick coral reef powder, quartz sand, silica fume, fly ash, sea water, superplasticizer, steel fiber ; Wherein, the composition and proportion of the concrete are as follows: ferric aluminate cement 690.2kg/m ³ ; fine coral reef powder 138.6kg/m ³ ; coarse coral reef powder 194.1kg/m ³ ; quartz sand 776.3kg/m ³ ; Ash 138.6kg/m ³ ; fly ash 34.7kg/m ³ ; seawater 182.3kg/m ³ ; superplasticizer 41.6kg/m ³ ; steel fiber 140.4kg/m ³ . 2. a kind of seawater mixing coral reef sand C150UHPC and preparation method thereof according to claim 1, is characterized in that: described cement is iron aluminate cement, and its chemical composition is silicon dioxide (SiO ₂ ) 12.4%, Alumina (Al ₂ O ₃ ) 26.45%, iron oxide (Fe ₂ O ₃ ) 9.50%, calcium oxide (CaO) 48.5%, sulfur trioxide (SO ₃ ) 1.46%, loss on ignition 0.15%. 3. a kind of seawater mixing coral reef sand C120UHPC according to claim 1, is characterized in that: described fine coral reef powder and thick coral reef powder are both natural original or broken coral reef by ball mill pulverization and sieving after making. The particle size of the fine coral reef powder is 1000 meshes, and the particle size of the coarse coral reef powder is 20-70 meshes. 4. a kind of seawater mixing coral reef sand C120UHPC according to claim 1, is characterized in that: described quartz sand is milky white, and its chemical composition is silicon dioxide (SiO ₂ ) content 99.5%～99.9%, dioxide trioxide The carbon (Fe ₂ O ₃ ) content is less than 0.005%, and the particle size is 0.45~0.85mm. 5. a kind of seawater mixing coral reef sand C120UHPC according to claim 1, is characterized in that: described silica fume is gray-black, and its chemical composition is silicon dioxide (SiO ₂ ) content 94.5%～96%, magnesium oxide (MgO) content 0.97%, carbon trioxide (Fe ₂ O ₃ ) content 0.83%, specific surface area 23000m ² /kg, specific gravity 2400kg/m ³ , particle size 0.05

. 6. a kind of seawater mixing coral reef sand C120UHPC according to claim 1, is characterized in that: described fly ash is off-white, and its chemical composition is silicon dioxide (SiO ₂ ) content 60.98%, aluminum oxide ( Al ₂ O ₃ ) content is 24.47%, carbon trioxide (Fe ₂ O ₃ ) content is 6.7%, calcium oxide (CaO) content is 5.1%, magnesium oxide (MgO) content is 0.68%, and the particle size is 8

. 7. a kind of seawater mixing culture mixed coral reef sand C120UHPC according to claim 1, is characterized in that: described superplasticizer is the polycarboxylate superplasticizer produced by BASF (China) Co., Ltd., the water-reducing agent The agent is a liquid water reducing agent, and the steel fiber is a straight copper-coated steel fiber with a length of 12-14 mm and a diameter of 0.21-0.23 mm. 8. a kind of seawater mixing coral reef sand C120UHPC according to claim 1, is characterized in that: 1 day compressive strength of described concrete is 30Mpa, 3 days compressive strength is 58Mpa, 7 days compressive strength is 88Mpa, The 28-day compressive strength is 122Mpa, the 28-day flexural strength is 15.5MPa, the 28-day tensile strength is 6.98MPa, and the expansion is 211mm. 9. a preparation method of seawater mixing and raising coral reef sand C120UHPC, is characterized in that: its stirring method comprises the following steps: Step 1: Weigh a specific amount of quartz sand, fine coral reef powder and coarse coral reef powder according to the ratio and place them in a mixer, and the mixing time is not less than 5min under low speed conditions; Step 2: Add specific amounts of cement, silica fume and fly ash according to the ratio and place them in the mixer, and the mixing time is not less than 5min under low speed conditions; Step 3: Weigh a specific amount of water and a high-efficiency water reducer according to the ratio, mix and stir the two evenly, then add them to the mixer, stir at low speed for 2 minutes, and then stir at high speed for 5 minutes, until the mixture becomes fluid; Step 4: After step 3 is completed, weigh a specific amount of steel fibers according to the ratio, slowly add them into the agitator, and continue to stir at high speed for 10min after the addition is complete; Step 5: After step 4 is completed, slowly pour the mixed concrete into the mold, tap lightly with a small hammer 20 times on both sides of the mold, and then place it in a standard curing room for 1 day of curing; Step 6: After the completion of Step 5, the concrete is demolded and cured, and after the curing is completed, the seawater-mixed coral reef sand C120UHPC is obtained. 10. the preparation method of a kind of seawater mixing coral reef sand C120UHPC according to claim 9, it is characterized in that: in step 6, the conservation method of concrete can be: 1) concrete is placed in standard curing room, with wet The test piece was covered with sackcloth, and high-frequency intermittent watering was performed to keep the sackcloth in a wet state; 2) The specimen was placed in water for maintenance, and the temperature in the water was guaranteed to be 20 °C.