Preparation and application of sand-free porous concrete

Abstract

The invention provides preparation and application of sand-free porous concrete. The sand-free porous concrete comprises the following raw materials: 490-630 Kg / m < 3 > of cement; 750-1150 kg / m < 3 > of coarse aggregate; 120-170kg / m < 3 > of water; 120-360 kg / m < 3 > of an early strength agent; 110-350 kg / m < 3 > of a water reducing agent; the preparation method comprises the following steps: mixing the cement, the coarse aggregate and the water according to a certain proportion, ensuring uniform stirring, discharging air in the concrete through vibration to form a uniform pore structure, pouring and molding, covering with a transparent plastic film, and carrying out wet maintenance. The sand-free porous macroporous concrete is widely applied to the fields of buildings, traffic, metallurgy, chemical engineering and the like. The composite material has the advantages of low density, light weight and high strength, is a novel light high-strength material, has a porous structure and is filled with gas, so that the composite material has better heat insulation performance and sound insulation performance. The material not only has good environmental protection performance, but also conforms to the concept of sustainable development.

Description

Technical Field

[0001] The invention relates to the technical field of concrete, and in particular to the preparation and application of sand-free porous concrete. Background Art

[0002] At present, sand is mostly used in the preparation of ordinary concrete. The main reason is that the physical properties of sand are suitable for concrete preparation and its cost is low. The main disadvantages of ordinary concrete are heavy weight, low tensile strength, easy cracking, slow hardening speed, long production cycle, etc. These disadvantages affect the application and performance of concrete in construction. First, the sand-containing concrete Deadweight Larger, the gravity density of reinforced concrete is about 25kN / m 3 , which is heavier than masonry and wood. Although it is lighter than steel, the cross-sectional dimensions of the structure are large, and its own weight far exceeds the weight of steel structures of the same span or height, which will affect construction in areas with poor foundations. Secondly, concrete has low tensile strength and low ultimate elongation. When the shrinkage value exceeds the ultimate elongation of concrete, the concrete will crack and cause leakage. In addition, concrete hardens slowly and has a long production cycle, which also limits its application in certain emergency projects. And the large demand for river sand is not conducive to the protection of river sand and water resources. In order to overcome these shortcomings, there is an urgent need for a concrete that is lighter in weight, has higher tensile strength and is more conducive to environmental protection. Summary of the invention

[0003] The purpose of the present invention is to provide a preparation and application of sand-free porous concrete. On the basis of traditional concrete, high-quality lightweight aggregate, expansion agent and other raw materials are added to generate a large number of bubbles during the mixing process to form a lightweight concrete with a porous structure. Compared with traditional concrete, sand-free macroporous concrete has the characteristics of low density, light weight and high porosity, and is a new type of building material with excellent lightweight thermal insulation performance.

[0004] The technical solution of the present invention is: in order to solve the above technical problems, the present invention provides a preparation and application of sandless porous concrete, the raw materials of ready-mixed concrete are screened, and the ingredients are mixed according to the proportion and process after screening. According to the mass fraction, the raw materials include:

[0005] The components and contents of each group are as follows:

[0006] Cement 490-630Kg / m 3 ;

[0007] Coarse aggregate 750-1150Kg / m 3 ;

[0008] Water 120-170Kg / m 3 ;

[0009] Early strength agent 120-360Kg / m 3 ;

[0010] Water reducing agent 110-350Kg / m 3 ;

[0011] Preparation method:

[0012] The preparation method of sandless porous concrete mainly includes the following steps:

[0013] Raw material preparation: The main raw materials include cement, coarse aggregate and water. Early strength agent and water reducing agent can also be added as needed.

[0014] Mixing: Mix cement, coarse aggregate and water in a certain proportion and ensure uniform mixing.

[0015] Vibration molding: The air in the concrete is expelled through vibration to form a uniform pore structure.

[0016] Curing: After casting, cover with transparent plastic film for wet curing, usually for 28 days. The cement used is commonly used silicate cement or kaolin cement, and slag silicate cement can also be used. Cement is mostly 42.5MPa and 52.5MPa grade cement;

[0017] The coarse aggregate used in the sandless porous concrete can be crushed stone, pebbles, or artificial lightweight aggregate, with particles with a diameter of ≥4.75mm; these coarse aggregates can be used alone or in combination, and the specific selection depends on the engineering needs and design requirements;

[0018] The sand-free porous concrete coarse aggregate is usually a single particle size of small size, such as 10-20mm or 10-30mm. This can make the void ratio;

[0019] The content of needle-like and flake-like particles in the sandless porous concrete coarse aggregate is not more than 15% by mass;

[0020] The mud content (including powder content) in the crushed stone should not be greater than 1%;

[0021] The water reducing agent: plasticizer, superplasticizer, etc. 1.6%-4.5%;

[0022] The early strength agent: in order to accelerate the concrete to reach the designed strength, the early strength agent is generally added in an amount of 1% to 2%.

[0023] The beneficial effects of the present invention are as follows: compared with the prior art, the present invention adopts coarse aggregate crushed stone, pebble particles, and artificial lightweight aggregate as coarse aggregate added to concrete, which has lower density and lighter weight. This lightweight characteristic makes sandless porous concrete more convenient in transportation and installation, and also reduces the requirements for the foundation structure. Sand porous concrete has higher strength and performs well when bearing loads, and is suitable for various structural requirements. Due to its porous structure, it can effectively absorb and isolate noise, and reduces dependence on river sand and water resources, which is conducive to environmental protection and sustainable development. DETAILED DESCRIPTION

[0024] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The present invention provides a preparation and application of sandless porous concrete, wherein the raw materials of the ready-mixed concrete are screened, and the ingredients are mixed according to the proportion and process after the screening. The raw materials include the following in terms of mass fraction:

[0026] The components and contents of each group are as follows:

[0027] Cement 490-630Kg / m 3 ;

[0028] Coarse aggregate 750-1150Kg / m 3 ;

[0029] Water 120-170Kg / m 3 ;

[0030] Early strength agent 120-360Kg / m 3 ;

[0031] Water reducing agent 110-350Kg / m 3 ;

[0032] Preparation method:

[0033] The preparation method of sandless porous concrete mainly includes the following steps:

[0034] Raw material preparation: The main raw materials include cement, coarse aggregate and water. Early strength agent and water reducing agent can also be added as needed.

[0035] Mixing: Mix cement, coarse aggregate and water in a certain proportion and ensure uniform mixing.

[0036] Vibration molding: The air in the concrete is expelled through vibration to form a uniform pore structure.

[0037] Curing: After casting, cover with transparent plastic film for wet curing, usually for 28 days. The cement used is commonly used silicate cement or kaolin cement, and slag silicate cement can also be used. Cement is mostly 42.5MPa and 52.5MPa grade cement;

[0038] The coarse aggregate used in the sandless porous concrete can be crushed stone, pebbles, or artificial lightweight aggregate, with particles with a diameter of ≥4.75mm; these coarse aggregates can be used alone or in combination, and the specific selection depends on the engineering needs and design requirements;

[0039] The sand-free porous concrete coarse aggregate is usually a single particle size of small size, such as 10-20mm or 10-30mm. This can make the void ratio;

[0040] The content of needle-like and flake-like particles in the sandless porous concrete coarse aggregate is not more than 15% by mass;

[0041] The mud content (including powder content) in the crushed stone should not be greater than 1%;

[0042] The water reducing agent: plasticizer, superplasticizer, etc. 1.6%-4.5%;

[0043] The early strength agent: in order to accelerate the concrete to reach the designed strength, the early strength agent is generally added in an amount of 1% to 2%;

[0044] Different types of water reducing agents can be selected according to specific conditions. The use of water reducing agents can increase the fluidity and viscosity of cement slurry, which is beneficial to the wrapping of aggregates. Early strength agents can be considered for winter construction.

[0045] The coarse aggregate used in the preferred sandless porous concrete can be crushed stone, pebbles, or artificial light aggregate. Old sandless concrete can also be used as coarse aggregate after being crushed. Using different coarse aggregates, the physical and mechanical properties of the materials are also different.

[0046] Sandless porous concrete is a porous aggregate structure formed by the bonding of coarse aggregate and cement paste. Since the strength of coarse aggregate is much higher than that of concrete, the bonding strength between coarse aggregate and cement paste is the weakest link of the material. The damage mainly occurs in the cement paste layer between the aggregate interface. Therefore, the type, strength and quantity of cementitious materials and cement play a key role in the strength of sandless porous concrete. In general, ordinary Portland cement should be used for sandless porous concrete, and slag Portland cement can also be used. Other types of cement should be determined through experiments. In order to ensure that sandless porous concrete has satisfactory strength, cement is mostly 42.5MPa and 52.5MPa grades.

[0047] The smaller the aggregate size of sandless porous concrete, the greater the porosity between aggregate particles, and the strength of the prepared concrete is higher. Therefore, sandless porous concrete aggregates usually use a single particle size of small size, such as 10-20mm or 10-30mm. This can make the porosity larger, and there is enough contact area between aggregate particles to ensure that the concrete has sufficient strength. The content of needle-like and flaky particles in coarse aggregates of sandless porous concrete should not exceed 15% by mass, and the mud content (including powder content) in crushed stone should not exceed 1%.

[0048] Sandless porous concrete has a wide range of applications in many fields:

[0049] Permeable pavement: Due to its good water permeability, sandless porous concrete is often used to make permeable pavement, which helps reduce urban waterlogging and urban heat island effect.

[0050] Ecological restoration: In ecological restoration projects, sandless porous concrete can be used for vegetation concrete to promote vegetation growth and improve the ecological environment.

[0051] Other applications: It can also be used in parking lots, sidewalks and other places that require water permeability.

[0052] Sandless porous concrete has good water permeability. Due to its large number of pores, it can quickly drain water and reduce water accumulation on the road.

[0053] Sandless porous concrete has a lower density and lighter weight. This lightweight feature makes sandless porous concrete more convenient during transportation and installation, and also reduces the requirements for the foundation structure.

[0054] Sandless porous concrete has higher strength and performs well under load, making it suitable for a variety of structural needs. Due to its porous structure, it can effectively absorb and isolate noise, and reduces dependence on river sand and water resources, contributing to environmental protection and sustainable development.

[0055] Eco-friendliness of sandless porous concrete: its water permeability helps improve the urban ecological environment, reduce the heat island effect and waste of water resources.

[0056] Due to its unique physical properties and ecological benefits, sandless porous concrete has broad application prospects in fields such as permeable pavement and ecological restoration.

[0057] In summary, the present invention has the advantages of low density, light weight and high strength. It is a new type of lightweight and high-strength material with a porous structure and is filled with gas inside, so it can have good thermal insulation and sound insulation properties. This material not only has good environmental protection performance, but also conforms to the concept of sustainable development. Therefore, sand-free porous macroporous concrete has been widely used in the fields of construction, transportation, metallurgy, chemical industry, etc. Application in the construction field: as insulation boards, wall materials, roofing materials, etc. Application in roads and transportation fields: as light fillers, isolation belts, etc. Application in metallurgy and chemical industry: as thermal insulation materials, furnace lining materials, etc. Application in environmental protection field: as sewage treatment materials, landfill lining materials, etc. In short, sand-free porous concrete is a new type of building material with broad application prospects, which can meet people's various needs for building quality, environmental protection, comfort, etc.

[0058] In the above description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed above.

Claims

1. Preparation and application of sandless porous concrete, characterized by: The raw materials for ready-mixed concrete are screened and mixed according to the proportion and process. The raw materials are calculated by weight. The components and contents of each component are as follows: Cement 490-630Kg / m 3 , coarse aggregate 750-1150K, water 120-170Kg / m 3 , early strength agent 120-360Kg / m 3 , water reducing agent 110-350Kg / m 3 .

2. The preparation and application of the sandless porous concrete according to claim 1, characterized in that: The cement may be commonly used silicate cement or kaolin cement, or slag silicate cement. Cement of 42.5MPa and 52.5MPa grade is often used.

3. The preparation and application of the sandless porous concrete according to claim 1, characterized in that: The stone coarse aggregate can be crushed stone, pebble, or artificial light aggregate, with particles having a diameter of ≥4.75 mm; these coarse aggregates can be used alone or in combination, and the specific selection depends on the engineering needs and design requirements.

4. The preparation and application of the sandless porous concrete according to claim 1, characterized in that: The water reducing agent: plasticizer, superplasticizer, etc. 1.6%-4.5%.

5. The preparation and application of the sandless porous concrete according to claim 1, characterized in that: The early strength agent is generally added in an amount of 1% to 2%.

6. The preparation and application of the sandless porous concrete according to claim 1, characterized in that: The coarse aggregate is usually a single particle size with a small size, such as 10-20 mm or 10-30 mm.

7. The preparation and application of the sandless porous concrete according to claim 1, characterized in that: The content of needle-like and flaky particles in the coarse aggregate is not more than 15% by mass.

8. The preparation and application of the sandless porous concrete according to claim 1, characterized in that: The preparation method of the sandless porous concrete mainly includes the following steps: raw material preparation: the main raw materials include cement, coarse aggregate and water. If necessary, early strength agent and water reducing agent can also be added, mixing and stirring: cement, coarse aggregate and water are mixed in a certain proportion to ensure uniform mixing, vibration molding: the air in the concrete is discharged by vibration to form a uniform pore structure, curing: after pouring and molding, cover with transparent plastic film for wet curing, usually the curing time is 28 days.

9. The preparation and application of the sandless porous concrete according to claim 1, characterized in that: The sandless porous concrete is used in the construction field: as insulation boards, wall materials, roofing materials, etc., in the road and transportation field: as light fillers, isolation belts, etc., in the metallurgy and chemical industry field: as thermal insulation materials, furnace lining materials, etc., and in the environmental protection field: as sewage treatment materials, landfill lining materials, etc.