Low-clinker concrete for reinforcing high saline-alkali soil as well as preparation method and application of low-clinker concrete

Abstract

The invention relates to low-clinker concrete for reinforcing high saline-alkali soil as well as a preparation method and application of the low-clinker concrete, and belongs to the technical field of building materials. The concrete is formed by taking a high-sulfur-erosion-resistance gelling system as a matrix and taking gravel aggregate and a polycarboxylic acid water reducing agent as auxiliary materials, according to GB / T 50081-2019, the 28-day compressive strength of the concrete is larger than or equal to 60 MPa, the 150-time circulation sulfate corrosion resistance coefficient K is larger than or equal to 0.90, the concrete can be directly poured into an anti-erosion component or serve as a plastering layer / formwork to wrap an existing structure, the concrete is particularly suitable for the high-saline-alkali soil sulfate erosion environment, the problems that traditional concrete is prone to being eroded and damaged in high-saline-alkali areas, and the maintenance cost is high are solved, and the service life of the concrete is prolonged. The environment-friendly performance and the long-acting protection performance are achieved.

Description

Technical Field

[0001] This invention relates to a low-clinker concrete for reinforcing high-salt-alkali land, its preparation method, and its application, belonging to the field of building materials technology. Background Technology

[0002] my country has a vast territory with significant geological differences across regions. Taking Xinjiang as an example, over 30% of the land in Xinjiang is saline-alkali soil, and the high concentration of SO42- in groundwater leads to a combination of gypsum- and ettringite-type erosion in concrete structures. Traditional silicate cement concrete cracks and powders within a few years.

[0003] In existing ordinary Portland cement, cement clinker and gypsum account for more than 80%, while conventional ultra-high performance concrete (UHPC) also relies on a much higher amount of cementitious material per cubic meter than ordinary cement concrete, both of which have the problem of large carbon emissions.

[0004] Industrial byproduct gypsum in Xinjiang has high annual emissions due to power generation needs, and is currently mainly used as a cement retarder, resulting in low utilization rates. Agricultural byproduct rice husk ash is abundant in Xinjiang's agricultural areas, but its utilization rate is also low.

[0005] In summary, there is an urgent need to develop a low-clinker concrete that is low in clinker, highly corrosion-resistant, and can utilize industrial and agricultural by-products. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, one of the objectives of this invention is to provide a low-clinker concrete for reinforcing high-salt-alkali land. This concrete uses a high-sulfur-erosion-resistant cementitious system as its matrix, supplemented with sand and gravel aggregates and polycarboxylate superplasticizer. According to GB / T 50081-2019, the concrete has a 28-day compressive strength ≥60MPa and a sulfate corrosion resistance coefficient K≥0.90 after 150 cycles. It can be directly cast as an anti-erosion component or used as a finishing layer / mold to cover existing structures. It is particularly suitable for sulfate-eroded environments in high-salt-alkali land, solving the problems of traditional concrete's susceptibility to erosion and high maintenance costs in high-salt-alkali areas, while also possessing both environmental friendliness and long-term protective performance.

[0007] The second objective of this invention is to provide a method for preparing low-clinker concrete for reinforcing high-salt-alkali land.

[0008] The third objective of this invention is to provide an application of low-clinker concrete for reinforcing high-salt-alkali land.

[0009] To achieve the objectives of this invention, the following technical solutions are provided.

[0010] A low-clinker concrete for reinforcing high-salt-alkali land, wherein the low-clinker concrete is composed of a high sulfur-resistant cementitious system as the matrix, supplemented with sand and gravel aggregates and polycarboxylate superplasticizer, wherein the dosage of each raw material component is: 400 kg / m³ of high sulfur-resistant cementitious system. 3 ~650kg / m 3 , sand 600kg / m 3 ~1200kg / m 3 Crushed stone 600kg / m 3 ~1200kg / m 3 Polycarboxylate superplasticizer 6kg / m 3 ~20kg / m 3 140 kg / m³ of water 3 ~160kg / m 3 .

[0011] The particle size of the crushed stone is 5mm to 15mm.

[0012] Furthermore, a high sulfur erosion resistant cementing system of 400 kg / m 3 ~600kg / m 3 , sand 800kg / m 3 ~900kg / m 3 800 kg / m³ of crushed stone 3 ~900kg / m 3 Polycarboxylate superplasticizer 8kg / m 3 ~15kg / m 3 Water 145kg / m 3 ~160kg / m 3 .

[0013] Taking the total mass of the raw materials for the high sulfur erosion resistant cementitious system as 100%, the components and their mass fractions are as follows:

[0014] Portland cement clinker 3% to 15%,

[0015] Sulfate activator 5% ~ 25%,

[0016] 60% to 85% of dense, waterproof modified admixture;

[0017] Furthermore, the sulfate activator is prepared by the following method:

[0018] The phosphogypsum was calcined at 150℃~500℃ for 2 hours, and then ground until the specific surface area was ≥300m². 2 / kg.

[0019] Furthermore, taking the total mass of the raw materials of the high sulfur erosion resistant cementitious system as 100%, the components and their mass fractions are as follows:

[0020] 5% to 10% silicate cement clinker

[0021] Sulfate activator 10% ~ 20%,

[0022] 75% to 80% of dense, waterproof modified admixture.

[0023] Furthermore, taking the total mass of the aforementioned dense waterproof modified admixture raw material as 100%, the components and their mass fractions are as follows:

[0024]

[0025] Furthermore, the micro-nano rice husk ash must meet the following specifications: amorphous SiO2 content > 85%, and particle size of 1 nm to 500 nm.

[0026] Furthermore, the micro / nano rice husk ash can be prepared using the following method:

[0027] Rice husks are calcined at a constant temperature of 400℃~600℃ for 2h~4h, and then ground to obtain the product.

[0028] Furthermore, the hydrophobic silane powder is isobutyltriethoxysilane or octyltrimethoxysilane.

[0029] Furthermore, the specific surface area of ​​the dense waterproof modified admixture is ≥450m². 2 / kg, and further, the specific surface area of ​​the dense waterproof modified admixture is 450m². 2 / kg~800m 2 / kg.

[0030] A method for preparing low-clinker concrete for reinforcing high-salinity and alkaline land, as described in this invention, comprises the following steps:

[0031] (1) Mix cement clinker, sulfate activator and dense waterproof modified admixture, stir thoroughly and evenly to form a high sulfur erosion resistant cementitious system;

[0032] (2) Mix the high sulfur erosion resistant cementitious system, sand, gravel and polycarboxylate superplasticizer, and stir thoroughly to prepare a low clinker concrete for high salinity and alkali land reinforcement.

[0033] Furthermore, the dense, waterproof modified admixture was prepared using the following method:

[0034] Mineral powder, steel slag powder, micro-nano rice husk ash, and hydrophobic silane powder were dry-mixed evenly to prepare a dense, waterproof modified admixture.

[0035] An application of the low-clinker concrete for reinforcing high-salt-alkali land according to the present invention is to directly cast the low-clinker concrete into anti-erosion components such as pile foundations, pipe corridors or retaining walls; or to use it as a finishing layer or precast mold to cover the surface of existing concrete structures.

[0036] Furthermore, the thickness of the finishing layer or precast mold shell is 15mm to 50mm.

[0037] Beneficial effects

[0038] (1) This invention provides a low-clinker concrete for reinforcing high salinity and alkalinity land. The concrete is based on a high sulfur erosion resistant cementitious system, supplemented with sand and gravel aggregates and polycarboxylate superplasticizer. According to GB / T50081-2019, the concrete has a 28-day compressive strength ≥60MPa and a sulfate corrosion resistance coefficient K ≥0.90 after 150 sulfate erosion cycles. It can be directly cast as an anti-erosion component or used as a plastering layer / mold to cover existing structures. It is particularly suitable for sulfate erosion environments in high salinity and alkalinity land, solving the problems of traditional concrete being easily eroded and damaged in high salinity and alkalinity areas and having high maintenance costs. It has both environmental protection and long-term protective performance.

[0039] (2) The present invention provides a low clinker concrete for reinforcement of high salinity and alkalinity land. The concrete realizes the resource utilization of industrial by-product phosphogypsum, which is first calcined and then ground to make sulfate activator, which can improve the sulfate erosion resistance of the high sulfur erosion resistant cementitious system.

[0040] (3) The present invention provides a low clinker concrete for reinforcement of high salinity and alkali land. The concrete realizes the resource utilization of rice husk ash, an agricultural by-product of Xinjiang with abundant resources. Micro-nano rice husk ash is used in the dense waterproof modified admixture to improve the compactness of the matrix through the dual effects of filling micropores and regulating the consistency of the paste.

[0041] (4) The present invention provides a low clinker concrete for reinforcement of high salinity and alkalinity land. The micro-nano rice husk ash used in the concrete is obtained by calcining rice husks at a constant temperature of 400℃~600℃ for 2h~4h, which can improve the activity of rice husk ash and reduce the loss on ignition.

[0042] (5) The present invention provides a low clinker concrete for reinforcement of high salinity and alkalinity land, wherein the use of hydrophobic silane powder in the dense waterproof modified admixture of the concrete can improve the waterproof and moisture-proof performance of the concrete.

[0043] (6) The present invention provides a low clinker concrete for reinforcement of high salinity and alkalinity land. The use of steel slag powder and mineral powder in the compact and waterproof modified admixture of the concrete not only further realizes the utilization of solid waste, but also improves the overall compactness of the concrete. Detailed Implementation

[0044] The present invention will be described in detail below with reference to specific embodiments, but this is not intended to limit the scope of the present invention.

[0045] Example 1

[0046] A low-clinker concrete for reinforcing high-salt-alkali land, wherein the low-clinker concrete is composed of a high sulfur-resistant cementitious system as the matrix, supplemented with sand and gravel aggregates and polycarboxylate superplasticizer, wherein the dosage of each raw material component is: 500 kg / m³ of high sulfur-resistant cementitious system. 3 Sand 850kg / m 3 900 kg / m³ of crushed stone 3 Polycarboxylate superplasticizer 12kg / m 3 Water 145kg / m 3 The particle size of the crushed stone is 5mm to 7mm.

[0047] Taking the total mass of the raw materials for the high sulfur erosion resistant cementitious system as 100%, the components and their mass fractions are as follows:

[0048] 5% silicate cement clinker

[0049] Sulfate activator 15%, 80% dense, waterproof modified admixture;

[0050] The sulfate activator was prepared by the following method:

[0051] The phosphogypsum was calcined at 300℃ for 2 hours and then ground until the specific surface area was 300 m². 2 / kg.

[0052] Based on the total mass of the aforementioned dense waterproof modified admixture raw material as 100%, the components and their mass fractions are as follows:

[0053]

[0054]

[0055] The hydrophobic silane powder is isobutyltriethoxysilane.

[0056] The micro-nano rice husk ash is obtained by calcining rice husks at 400℃ for 2 hours and then grinding them. The particle size is 1nm to 500nm. X-ray fluorescence spectroscopy (XRF) analysis shows that the SiO2 content is 90%.

[0057] According to the Blaine method test, the specific surface area of ​​the dense waterproof modified admixture is 500 m². 2 / kg.

[0058] A method for preparing low-clinker concrete for reinforcing high-salinity and alkaline land, as described in this embodiment, comprises the following steps:

[0059] (1) Mix cement clinker, sulfate activator and dense waterproof modified admixture, stir thoroughly and evenly to form a high sulfur erosion resistant cementitious system;

[0060] (2) Mix the high sulfur erosion resistant cementitious system, sand, gravel, polycarboxylate superplasticizer and water, and stir thoroughly to prepare a low clinker concrete for high salinity and alkali land reinforcement.

[0061] The dense waterproof modified admixture was prepared using the following method.

[0062] Mineral powder, steel slag powder, micro-nano rice husk ash, and hydrophobic silane powder were dry-mixed evenly to prepare a dense, waterproof modified admixture.

[0063] The low-clinker concrete used for high-salt-alkali land reinforcement described in this embodiment was directly cast into a pile foundation concrete mold shell with a thickness of 20mm. Its performance was then tested as follows:

[0064] According to GB / T 50081 "Standard for Test Methods of Physical and Mechanical Properties of Concrete", the test results show that the 28-day compressive strength of low clinker concrete is 72 MPa.

[0065] According to the sulfate corrosion resistance test method in GB / T 50082, the test results show that the sulfate corrosion resistance coefficient is 0.92 after 150 cycles.

[0066] The above test results demonstrate that the low-clinker concrete for high-salt-alkali land reinforcement prepared in this embodiment is particularly suitable for sulfate erosion environments in high-salt-alkali lands. It solves the problems of traditional concrete being easily eroded and damaged in high-salt-alkali areas and having high maintenance costs, and has both environmental friendliness and long-term protective performance.

[0067] Example 2

[0068] A low-clinker concrete for reinforcing high-salt-alkali land, wherein the low-clinker concrete is composed of a high sulfur-resistant cementitious system as the matrix, supplemented with sand and gravel aggregates and polycarboxylate superplasticizer, wherein the dosage of each raw material component is: 600 kg / m³ of high sulfur-resistant cementitious system. 3 , sand 900kg / m 3 800 kg / m³ of crushed stone 3 Polycarboxylate superplasticizer 15kg / m 3 150kg / m 3 The particle size of the crushed stone is 5mm to 10mm.

[0069] Taking the total mass of the raw materials for the high sulfur erosion resistant cementitious system as 100%, the components and their mass fractions are as follows:

[0070] 10% silicate cement clinker

[0071] Sulfate activator 10%, 80% dense, waterproof modified admixture;

[0072] The sulfate activator was prepared by the following method:

[0073] The phosphogypsum was calcined at 150℃ for 2 hours and then ground until the specific surface area was 350 m². 2 / kg.

[0074] Based on the total mass of the aforementioned dense waterproof modified admixture raw material as 100%, the components and their mass fractions are as follows:

[0075]

[0076] The hydrophobic silane powder is isobutyltriethoxysilane.

[0077] The micro-nano rice husk ash is obtained by calcining rice husks at 600℃ for 4 hours and then grinding them. The particle size is 1nm to 500nm, and XRF testing shows that the SiO2 content is 93%.

[0078] According to the Blaine method test, the specific surface area of ​​the dense waterproof modified admixture is 520 m². 2 / kg.

[0079] A method for preparing low-clinker concrete for reinforcing high-salinity and alkaline land, as described in this embodiment, comprises the following steps:

[0080] Same preparation method as in Example 1.

[0081] The low-clinker concrete used for high-salt-alkali land reinforcement described in this embodiment was prepared into a 30mm thick plaster layer and applied to the surface of the existing concrete structure. Its performance was then tested as follows:

[0082] According to GB / T 50081 "Standard for Test Methods of Physical and Mechanical Properties of Concrete", the test results show that the 28-day compressive strength of low clinker concrete is 78 MPa.

[0083] According to the test method for sulfate corrosion resistance in GB / T 50082, the test results show that the sulfate corrosion resistance coefficient is 0.95 after 150 cycles.

[0084] The test results above demonstrate that the low-clinker concrete for high-salt-alkali land reinforcement described in this embodiment solves the problems of traditional concrete being easily eroded and damaged and having high maintenance costs in high-salt-alkali areas, while also possessing both environmental friendliness and long-term protective performance.

[0085] Example 3

[0086] A low-clinker concrete for reinforcing high-salt-alkali land, wherein the low-clinker concrete is composed of a high sulfur-resistant cementitious system as the matrix, supplemented with sand and gravel aggregates and polycarboxylate superplasticizer, wherein the dosage of each raw material component is: 400 kg / m³ of high sulfur-resistant cementitious system. 3 , sand 800kg / m 3 900 kg / m³ of crushed stone 3 Polycarboxylate superplasticizer 8kg / m 3 Water 160kg / m 3 The particle size of the crushed stone is 5mm to 15mm.

[0087] Taking the total mass of the raw materials for the high sulfur erosion resistant cementitious system as 100%, the components and their mass fractions are as follows:

[0088] 5% silicate cement clinker

[0089] Sulfate activator 20%,

[0090] 75% dense, waterproof modified admixture;

[0091] The sulfate activator was prepared by the following method:

[0092] The phosphogypsum was calcined at 500℃ for 2 hours and then ground until the specific surface area was 380 m2 / kg.

[0093] Based on the total mass of the aforementioned dense waterproof modified admixture raw material as 100%, the components and their mass fractions are as follows:

[0094]

[0095] The hydrophobic silane powder is octyltrimethoxysilane.

[0096] The micro-nano rice husk ash is obtained by calcining rice husks at 500℃ for 3 hours and then grinding them. The particle size is 1nm to 500nm. XRF testing shows that the SiO2 content is 94%.

[0097] According to the Blaine method test, the specific surface area of ​​the dense waterproof modified admixture is 530 m². 2 / kg.

[0098] A method for preparing low-clinker concrete for reinforcing high-salinity and alkaline land, as described in this embodiment, comprises the following steps:

[0099] Same preparation method as in Example 1.

[0100] The low-clinker concrete used for high-salt-alkali land reinforcement described in this embodiment was prepared into a 50mm thick precast mold shell to cover the surface of the existing concrete structure, and its performance was tested as follows:

[0101] According to GB / T 50081 "Standard for Test Methods of Physical and Mechanical Properties of Concrete", the test results show that the 28-day compressive strength of low clinker concrete is 65 MPa.

[0102] According to the test method for sulfate corrosion resistance in GB / T 50082, the test results show that the sulfate corrosion resistance coefficient is 0.90 after 150 cycles.

[0103] The test results above demonstrate that the low-clinker concrete for high-salt-alkali land reinforcement described in this embodiment solves the problems of traditional concrete being easily eroded and damaged and having high maintenance costs in high-salt-alkali areas, while also possessing both environmental friendliness and long-term protective performance.

Claims

1. A low-clinker concrete for reinforcing high-salinity and alkaline soils, characterized in that: The low-clinker concrete is based on a high sulfur-resistant cementitious system, supplemented with sand and gravel aggregates and polycarboxylate superplasticizer. The dosage of each raw material component is: 400 kg / m³ of high sulfur-resistant cementitious system. 3 ~650kg / m 3 , sand 600kg / m 3 ~1200kg / m 3 Crushed stone 600kg / m 3 ~1200kg / m 3 Polycarboxylate superplasticizer 6kg / m 3 ~20kg / m 3 140 kg / m³ of water 3 ~160kg / m 3 The particle size of the crushed stone is 5mm to 15mm.

2. The low-clinker concrete for reinforcing high-salinity and alkaline soils according to claim 1, characterized in that: High sulfur erosion resistant cementitious system 400kg / m 3 ~600kg / m 3 , sand 800kg / m 3 ~900kg / m 3 800 kg / m³ of crushed stone 3 ~900kg / m 3 Polycarboxylate superplasticizer 8kg / m 3 ~15kg / m 3 Water 145kg / m 3 ~160kg / m 3 .

3. A low-clinker concrete for reinforcing high-salinity and alkaline soils according to claim 1 or 2, characterized in that: With the total mass of the raw materials for the high sulfur erosion resistant cementitious system being 100%, the components and their mass fractions are as follows: Portland cement clinker 3% to 15%, Sulfate activator 5% ~ 25%, 60% to 85% of dense, waterproof modified admixture.

4. The low-clinker concrete for reinforcing high-salinity and alkaline soils according to claim 3, characterized in that: With the total mass of the raw materials for the high sulfur erosion resistant cementitious system being 100%, the components and their mass fractions are as follows: 5% to 10% silicate cement clinker Sulfate activator 10% ~ 20%, 75% to 80% of dense, waterproof modified admixture.

5. The low-clinker concrete for reinforcing high-salinity and alkaline soils according to claim 3, characterized in that: The sulfate activator was prepared by the following method: The phosphogypsum was calcined at 150℃~500℃ for 2 hours and then ground until the specific surface area was ≥300m². 2 / kg; Based on the total mass of the dense waterproof modified admixture raw material as 100%, the components and their mass fractions are as follows:

6. The low-clinker concrete for reinforcing high-salinity and alkaline soils according to claim 5, characterized in that: The hydrophobic silane powder is isobutyltriethoxysilane or octyltrimethoxysilane; The micro-nano rice husk ash must meet the following specifications: amorphous SiO2 content > 85%, and particle size of 1nm to 500nm; The specific surface area of ​​the dense waterproof modified admixture is ≥450m². 2 / kg.

7. The low-clinker concrete for reinforcing high-salinity and alkaline soils according to claim 6, characterized in that: The micro-nano rice husk ash is prepared by calcining rice husks at a constant temperature of 400℃~600℃ for 2h~4h and then grinding them; the specific surface area of ​​the dense, waterproof modified admixture is 450m². 2 / kg~800m 2 / kg.

8. A method for preparing low-clinker concrete for reinforcing high-salinity and alkaline land as described in any one of claims 1 to 7, characterized in that: (1) Mix cement clinker, sulfate activator and dense waterproof modified admixture, stir thoroughly and evenly to form a high sulfur erosion resistant cementitious system; (2) Mix the high sulfur erosion resistant cementitious system, sand, gravel and polycarboxylate superplasticizer, and stir thoroughly to prepare a low clinker concrete for high salinity and alkali land reinforcement. The dense, waterproof modified admixture was prepared using the following method: Mineral powder, steel slag powder, micro-nano rice husk ash, and hydrophobic silane powder were dry-mixed evenly to prepare a dense, waterproof modified admixture.

9. An application of low-clinker concrete for reinforcing high-salinity and alkaline soils as described in any one of claims 1 to 7, characterized in that: Low-clinker concrete can be directly cast into anti-corrosion components for pile foundations, pipe galleries, or retaining walls; or used as a finishing layer or precast mold to cover the surface of existing concrete structures.

10. The application of low-clinker concrete for reinforcing high-salinity and alkaline soils according to claim 9, characterized in that: The thickness of the finishing layer or precast mold shell is 15mm to 50mm.

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