Concrete, concrete precast block and disassembly-free bottom die steel bar truss floor support plate

Abstract

The invention discloses concrete, a concrete precast block and a disassembly-free bottom die steel bar truss floor support plate, and the concrete comprises the following components: cement, fly ash, phosphogypsum, machine-made sand, gravel particles, water and an additive, the weight ratio of the cement to the fly ash to the phosphogypsum to the machine-made sand to the gravel to the water to the additive is 1: 0.31: 0.03: 2.66: 3.13: 0.53: 0.02; the specific surface area ratio of the machine-made sand to the gravel particles is (1: 5)-(1: 6). The specific surface area ratio of the concrete machine-made sand to the gravel particles is 1: 5-1: 6, the larger the specific surface area is, the more powder needs to be adsorbed, the use amount of the gravel is increased, the gravel can absorb heat and well dissipate heat, and the large use amount of the gravel can effectively solve the problem of concrete cracking caused by too high hydration heat temperature.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of building materials, and particularly relates to a concrete, a concrete precast block and a demolding-free bottom mold steel bar truss floor support plate. BACKGROUND

[0002] Traditional cast-in-situ concrete floor needs to rely on wood formwork or steel formwork as temporary support, and has problems of complex formwork removal process, long construction period and material waste. In order to improve the construction efficiency, steel bar truss floor support plates (such as profiled steel sheet composite floor) are widely used, but still have defects of insufficient fireproof and soundproof performance.

[0003] The demolding-free bottom mold steel bar truss floor support plate is optimized on this basis, and a precast concrete plate or a fiber cement plate is used as a permanent bottom mold, and the upper cast-in-situ concrete is combined with the steel bar truss to form a whole force structure.

[0004] The demolding-free bottom mold steel bar truss floor support plate needs to use concrete, and the early concrete mix ratio is mostly dependent on high cement content, which is easy to cause hydration heat cracking. SUMMARY

[0005] To solve the technical problems existing in the prior art concrete, the present application provides a concrete to solve the problem of easy hydration heat cracking of concrete caused by too high cementitious material.

[0006] The concrete provided by the present application comprises the following components: cement, fly ash, phosphogypsum, machine-made sand, gravel particles, water, and admixture, and the proportion of each component in the weight of the concrete is: cement: fly ash: phosphogypsum: machine-made sand: gravel: water: admixture = 1:0.31:0.03:2.66:3.13:0.53:0.02; and the specific surface area ratio of the machine-made sand to the gravel particles is 1:5-1:6.

[0007] Further, the total phosphorus content of the phosphogypsum is <1.5%, and the fluorine content is <0.3%.

[0008] Further, the phosphogypsum is a fine powder with a specific surface area of ≥350m 2 / kg.

[0009] Further, the phosphogypsum comprises phosphogypsum and sodium sulfate, and 1-2% of sodium sulfate is added per ton of phosphogypsum.

[0010] Further, the phosphogypsum comprises phosphogypsum and calcium hydroxide, and 1-2% of calcium hydroxide is added per ton of phosphogypsum.

[0011] Further, the phosphogypsum content accounts for 2-3% of the total amount of cementitious materials.

[0012] Further, the admixture content accounts for 1.5-1.7% of the total amount of cementitious materials.

[0013] Further, the machine-made sand has a fineness modulus of 2.8-3.0 and a stone powder content of 8%-12%.

[0014] The application further provides a concrete precast block formed by pouring the concrete provided by the application into a mold paved with a glass fiber mesh and curing.

[0015] The third aspect of the application further provides a demolding-free bottom mold steel bar truss floor support plate made of the concrete provided by the application.

[0016] The application has the following beneficial effects:

[0017] 1) The specific surface area ratio of the machine-made sand to the gravel particles is 1:5-1:6, the larger the specific surface area, the more the powder to be adsorbed, and the more the gravel to be used, according to the traditional concrete mixing ratio of cement:machine-made sand:gravel of 1:2:3, according to the specific surface area ratio of the machine-made sand to the gravel particles of 1:5-1:6, the gravel to be used is between 1000 and 1100, so that the concrete volume stability is optimal, and the shrinkage rate is optimal, and the phenomenon of more sand and less gravel in the traditional floor support plate concrete mixing ratio is changed, the problem of excessive use of cementitious materials, less coarse aggregate (gravel) and unstable skeleton, and thick surface floating slurry is solved.

[0018] 2) The specific surface area ratio of the machine-made sand to the gravel particles is 1:5-1:6, so that the gravel to be used is increased, and the more gravel to be used provides stable skeleton support, which indirectly promotes the early strength to be improved.

[0019] 3) The gravel can absorb heat and dissipate heat well, and the large amount of gravel can effectively solve the problem of concrete cracking caused by excessive hydration heat temperature. DETAILED DESCRIPTION

[0020] This section refers to a more complete description of the application, and the illustrative embodiments of the application are shown in the specification. However, the application can also be embodied in many different forms and should not be construed as being limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure fully and completely, and to fully convey the scope of the application to those skilled in the art.

[0021] The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the application. As used herein, the singular forms "a", "an" and "the" are intended to include plural forms, unless the context clearly indicates otherwise. It will be further understood that the terms "comprise" and "include" when used herein specify the presence of stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof.

[0022] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and will not be interpreted according to an idealized or very formal meaning unless specifically defined herein.

[0023] The formwork-free steel truss floor deck is a prefabricated building material that combines steel trusses with precast concrete slabs to form an integral load-bearing structure. This eliminates the need to remove the formwork during construction, simplifying the construction process and improving efficiency. This reduces the use and removal costs of formwork, lowering overall construction costs, simplifying the construction process, shortening the construction period, and improving efficiency. The steel trusses provide stable support, ensuring the structural safety of the floor slab. This reduces construction waste and meets the requirements of sustainable development.

[0024] The prefabrication process of steel truss floor decks without removing bottom formwork requires the use of concrete. Early concrete mixes often relied on high cement content, which was prone to hydration heat cracking, resulting in a low yield rate for steel truss floor decks without removing bottom formwork. To this end, the present invention provides a concrete that can effectively solve the problem of concrete cracking caused by excessively high hydration heat. This concrete is used in the prefabrication of steel truss floor decks without removing bottom formwork, effectively solving the problem of low yield rate for steel truss floor decks without removing bottom formwork due to concrete hydration heat cracking.

[0025] The concrete provided by the present invention includes the following components: cement, fly ash, phosphogypsum, machine-made sand, crushed stone particles, water, and admixtures. The proportions of the components by weight of the concrete are: cement: fly ash: phosphogypsum: machine-made sand: crushed stone: water: admixture = 1:0.31:0.03:2.66:3.13:0.53:0.02.

[0026] Cement: fly ash: phosphogypsum: machine-made sand: gravel: water: admixture = 1:0.31:0.03:2.66:3.13:0.53:0.02 refers to the ratio of cement, fly ash, phosphogypsum, machine-made sand, gravel, water, and admixture required for a certain amount of concrete. For example, if 10kg of cement is required, the amounts of fly ash, phosphogypsum, machine-made sand, gravel, water, and admixture are: 3.1kg, 0.3kg, 26.6kg, 31.3kg, 5.3kg, and 0.2kg, respectively.

[0027] The ratio of the specific surface area of the machine-made sand to the specific surface area of the gravel particles is close to 1:6, the greater the specific surface area, the more powder needs to be adsorbed, according to the traditional concrete mixing ratio of cement:machine-made sand:gravel 1:2:3, for example, the amount of gravel particles in the concrete is between 1000 and 1100, the volume stability of the concrete is optimal, the shrinkage rate is optimal, the amount of gravel is increased, the phenomenon of traditional floor slab concrete mixing ratio of more sand and less gravel is changed, the gravel can absorb heat and dissipate heat well, and the problem of concrete cracking caused by high hydration heat temperature can be solved by increasing the amount of gravel; and the application of phosphogypsum can also delay the phenomenon of high cement hydration heat temperature.

[0028] The increase of the amount of gravel can effectively solve the problem of unstable framework and thick surface floating slurry caused by excessive amount of cementitious materials and insufficient amount of aggregates.

[0029] The strength of the concrete itself is partly derived from the activity of the cement and the cementitious materials, and partly derived from the hardness of the aggregate, and the large amount of gravel provides stable framework support, which indirectly promotes the early strength. 2

[0030] The total phosphorus (P2O5) content of the phosphogypsum is <1.5%, and the fluorine (F) is <0.3%, to avoid delaying setting or corroding steel bars; the phosphogypsum is a fine powder with a specific surface area ≥350m 2 / kg, and the phosphogypsum mixed into the concrete in the form of fine powder can promote the hydration reaction.

[0031] In order to stimulate the activity of the phosphogypsum, the phosphogypsum in the present concrete includes phosphogypsum and sodium sulfate, 1-2% of sodium sulfate is added per ton of phosphogypsum; or the phosphogypsum includes phosphogypsum and calcium hydroxide, 1-2% of calcium hydroxide is added per ton of phosphogypsum, and the active ingredients in the phosphogypsum are stimulated by the reaction of sodium sulfate or calcium hydroxide with the phosphogypsum.

[0032] The amount of phosphogypsum accounts for 2-3% of the total amount of cementitious materials, and adding more will reduce the durability of the concrete, reduce the bonding strength of the concrete, and cause the strength to decrease.

[0033] The admixture in the present concrete is a water reducing agent, which should ensure that the final setting time of the concrete is between 8 and 10 hours, and existing water reducing agents such as polycarboxylic acid high-performance water reducing agent can be used. The amount of admixture accounts for 1.5-1.7% of the total amount of cementitious materials, low dosage leads to easy segregation of the concrete, high dosage leads to low water reducing rate, affects the water-binder ratio of the concrete, affects the strength of the concrete, and affects the production quality fluctuation.

[0034] The cementitious materials referred to in this paper refer to cement + fly ash + phosphogypsum.

[0035] The fineness modulus of the machine-made sand is 2.8-3.0, and the stone powder content is 8-12%.

[0036] The concrete prepared according to the proportioning of each component of the concrete has the following test results: 24h compressive strength ≥ 15MPa, 28d compressive strength meets the design C30 grade requirement; environmental temperature > 15℃, 24h natural curing can be demoulded, and the finished product rate ≥ 95%, without edge drop, which reduces the mold occupancy rate.

[0037] The concrete increases the waste materials such as gravel particles and machine-made sand, saves the amount of gel materials, and creates economic value through resource utilization, and has higher economic efficiency than traditional concrete mix.

[0038] The concrete is stirred according to the conventional ready-mixed concrete production preparation method, and the stirring time is not less than 3 minutes after the feeding is completed.

[0039] The concrete can be used in the required pouring occasions and prefabricated building materials according to the needs, such as being used for prefabricated concrete blocks. The stirred concrete is poured into the mold, and the mold is removed after 24h of natural curing, and the prefabricated building material is formed after 3 days of natural curing.

[0040] Before the concrete is poured into the mold, the entire mold is covered with a glass fiber mesh. After the concrete is poured and cured, the glass fiber mesh is embedded in the concrete.

[0041] It can also be used for the production of demoulding-free bottom mould steel bar truss floor support plates. The floor support plate is produced according to the conventional production method of demoulding-free bottom mould steel bar truss floor support plates. The concrete required is the concrete provided in the present application. The concrete can be directly poured, or a layer of glass fiber mesh can be laid before pouring the concrete. After the concrete is solidified, the glass fiber mesh is embedded in the concrete. Since the concrete can effectively solve the problem of concrete cracking caused by high hydration heat temperature, when it is used for the production of demoulding-free bottom mould steel bar truss floor support plates, the concrete thickness is between 20-25mm, and the concrete will not crack due to high temperature, thereby improving the finished product rate of the demoulding-free bottom mould steel bar truss floor support plates.

[0042] The embedding of the glass fiber mesh has the following advantages:

[0043] 1) Improved tensile strength and durability

[0044] The addition of the glass fiber mesh can significantly improve the tensile strength of the concrete, making it more durable, especially in places where concrete is prone to cracking. This material can disperse stress and reduce the occurrence and expansion of cracks, thereby prolonging the service life of the concrete structure.

[0045] 2) Enhanced thermal stability

[0046] The glass fiber mesh helps the concrete to maintain good structural stability in high temperature environments, preventing cracks caused by temperature changes. This thermal stability is particularly important for concrete structures exposed to extreme temperature environments.

[0047] 3) Improve fatigue resistance

[0048] Under repeated loads, concrete may develop fatigue cracks. Fiberglass mesh can effectively improve the fatigue resistance of concrete and reduce cracks and damage caused by long-term loads.

[0049] 4) Convenient construction

[0050] The concrete construction process using fiberglass mesh is simpler because the grid design allows for faster laying and greater coverage, which not only improves construction efficiency but also helps ensure the uniformity and integrity of the concrete structure.

[0051] 5) Environmental protection

[0052] Fiberglass mesh is an inorganic material that does not pollute the environment and can be recycled and reused after its service life, meeting environmental protection requirements.

[0053] This concrete, precast concrete blocks made with this concrete, and bottom formwork-free reinforced truss floor slabs made with this concrete combine phosphogypsum solid waste resources, increase the value of solid waste, reduce the use of cementitious materials, and meet the requirements of green building materials and green development. They save energy and reduce carbon emissions, alleviate environmental pressure, and effectively reduce the cost of concrete mix ratio. Phosphogypsum (processing cost is about 20 to 50 yuan / ton) is much lower than natural gypsum (100 to 200 yuan / ton). Resource utilization can create economic value. Based on the current market unit price of cement (280 to 330 yuan / ton), the application of phosphogypsum can save 2.6 to 2.8 yuan per cubic meter of concrete.

[0054] The present disclosure has been described using the aforementioned embodiments. However, the aforementioned embodiments are merely exemplary embodiments of the present disclosure. It should be noted that the disclosed embodiments do not limit the scope of the present disclosure. On the contrary, modifications and alterations made without departing from the spirit and scope of the present disclosure are within the scope of patent protection of the present disclosure.

Claims

1. A concrete, characterized in that: The concrete includes the following components: cement, fly ash, phosphogypsum, machine-made sand, crushed stone particles, water, and admixtures. The proportions of the components by weight of the concrete are: cement: fly ash: phosphogypsum: machine-made sand: crushed stone: water: admixture = 1:0.31:0.03:2.66:3.13:0.53:0.02; the ratio of the specific surface area of ​​the machine-made sand to the crushed stone particles is 1:5 to 1:

6.

2. The concrete according to claim 1, characterized in that: The total phosphorus content of the phosphogypsum is less than 1.5%, and the fluorine content is less than 0.3%.

3. The concrete according to claim 1, characterized in that: The phosphogypsum is a fine powder with a specific surface area of ​​≥350m2 / kg.

4. The concrete according to claim 1, characterized in that: The phosphogypsum includes phosphogypsum and sodium sulfate, and 1-2% of sodium sulfate is added to each ton of phosphogypsum.

5. The concrete according to claim 1, characterized in that: The phosphogypsum includes phosphogypsum and calcium hydroxide, and 1-2% of calcium hydroxide is added to each ton of phosphogypsum.

6. The concrete according to claim 1, characterized in that: The amount of phosphogypsum accounts for 2% to 3% of the total amount of the cementitious material.

7. The concrete according to claim 1, characterized in that: The admixture dosage accounts for 1.5% to 1.7% of the total amount of the cementitious material.

8. The concrete according to claim 1, characterized in that: The fineness modulus of the machine-made sand is 2.8-3.0, and the stone powder content is 8%-12%.

9. A precast concrete block, characterized in that: The prefabricated block is formed by pouring the concrete according to any one of claims 1 to 8 into a mold covered with a glass fiber mesh and curing the mold, and comprises concrete and glass fiber mesh.

10. A steel truss floor decking plate without dismantling bottom formwork, characterized in that: The deck is made of the concrete according to any one of claims 1 to 8.