Large-area anti-cracking floor and construction method thereof

Abstract

The present invention relates to a large-area anti-cracking floor and a construction method thereof, and belongs to the field of building construction. The large-area anti-cracking floor described in the present invention is casted with anti-cracking concrete during its construction, and the anti-cracking concrete contains the following components by weight: 120-150 parts of cement, 80-100 parts of sand, 25-45 parts of fly ash, 5-10 parts of water reducer, 12-15 parts of slag powder, 20-27 parts of anti-cracking agent, and 70-80 parts of water; wherein the anti-cracking agent contains 8-12 parts of modified peanut shells and 12-15 parts of composite fibers. In the present invention, anti-cracking concrete is used for casting, and anti-cracking concrete can better control the shrinkage deformation of concrete, and can effectively avoid cracks caused by the nature of concrete itself when it is used for laying in a large area.

Description

Technical Field

[0001] The invention belongs to the field of building construction and relates to a large-area anti-cracking ground and a construction method thereof. Background Art

[0002] With the application of concrete in human construction, large-area concrete and super-large-area concrete are also being used more and more widely. Due to its large area characteristics, it not only has requirements in terms of bearing capacity, but also has high requirements in terms of wholeness, crack control and aesthetics. That is, it requires all-round and full-process quality control in construction to achieve the expected effect.

[0003] In recent years, with the enhancement of my country's comprehensive national strength and the vigorous development of economic construction, the demand for ultra-large area concrete structures has been growing day by day. Large public buildings, factory structures, commercial centers, etc. with ultra-long and ultra-wide plane dimensions have emerged rapidly, and the number of ultra-long concrete structures has increased. Due to the good integrity of cast-in-place concrete structures, the relatively mature commercial concrete pumping technology in my country, and the low labor price, large or ultra-large area concrete structures are currently mainly cast-in-place.

[0004] The longer the concrete structure is, the greater the structural constraint caused by concrete shrinkage and temperature changes, and the more susceptible the concrete structure is to cracks.

[0005] Many concrete structures have cracks of varying degrees and forms during construction and use, which is a fairly common phenomenon. Modern scientific research on concrete strength and the experience provided by a large number of engineering practices have shown that cracks in structures are difficult to avoid.

[0006] The main cause of concrete cracking (cracks) is deformation, which includes temperature, humidity and uneven settlement, among which cracks caused by temperature changes account for the main part. Thermal expansion and contraction is a natural phenomenon of objects under the influence of temperature. The impact of temperature on the use of building structures has been paid attention to by people, and measures such as thermal insulation are taken to minimize the impact of ambient temperature.

[0007] The cracking of structural concrete is not only due to the insufficient tensile strength of concrete, but more importantly, the deformation exceeds the ultimate strain. Reinforced concrete can increase the ultimate tensile strength of concrete under normal reinforcement ratio. When the reinforcement ratio is too large (more than 5%), it will cause cracking due to excessive self-restraint. For super-large area structures, it is necessary to consider how to reduce or control cracks during construction and after they are put into use.

[0008] my country has a wealth of engineering practice in large or ultra-large concrete structures, and has explored many effective anti-cracking measures. In terms of materials, reducing the shrinkage value of concrete and improving the anti-cracking ability of concrete materials themselves can help solve the crack control problem of ultra-long concrete structures. Optimize the mix ratio of concrete, prepare low-shrinkage concrete or use shrinkage compensation concrete to reduce concrete shrinkage, use fiber concrete mixed with various fibers to improve the crack resistance of concrete, and use low-medium strength grade concrete for horizontal components such as beams and slabs to reduce the possibility of concrete cracking. Summary of the invention

[0009] The main purpose of the present invention is to provide a large-area anti-cracking floor and a construction method thereof. During the construction, anti-cracking concrete is poured to reduce the shrinkage of the concrete, improve its anti-cracking ability, and reduce the anti-cracking performance of the large-area floor.

[0010] The present invention adopts the following technical solutions to achieve the above purpose:

[0011] A large area anti-crack floor, which is constructed by pouring anti-crack concrete, wherein the anti-crack concrete contains the following components in parts by weight:

[0012] 120-150 parts of cement, 80-100 parts of sand, 25-45 parts of fly ash, 5-10 parts of water reducer, 12-15 parts of slag powder, 20-27 parts of anti-cracking agent, and 70-80 parts of water.

[0013] Furthermore, the anti-cracking agent contains 8-12 parts of modified peanut shells and 12-15 parts of composite fibers;

[0014] Furthermore, the composite fiber contains steel fiber and modified polypropylene fiber in a weight ratio of 1:(3-5).

[0015] The preparation method of the modified peanut shell of the present invention is:

[0016] Peanut shells and corn stalks are crushed, and paraformaldehyde, polyethylene glycol, phenol and hydrochloric acid are added in sequence, mixed, stirred continuously and heated to 100-120°C, kept stirring at 100-120°C for 1-1.5h, then cooled to 70-80°C, sodium hydroxide was added dropwise, and cooled to room temperature to obtain modified peanut shells.

[0017] Furthermore, the amount of corn stalk added is 5-8% of the weight of peanut shells, the amount of paraformaldehyde added is 1-1.2% of the weight of peanut shells, the amount of polyethylene glycol added is 15-20% of the weight of peanut shells, the amount of phenol added is 60-70% of the weight of peanut shells, the amount of hydrochloric acid added is 45-65% of the weight of peanut shells, and the amount of sodium hydroxide added is 85-90% of the weight of peanut shells.

[0018] Furthermore, the mass fraction of the hydrochloric acid is 35-37%, and the mass fraction of the sodium hydroxide is 35-40%.

[0019] The preparation method of the modified polypropylene fiber of the present invention is:

[0020] The dried polypropylene fiber is immersed in a sulfuric acid solution with a mass fraction of 60-70% for 1.5-2 hours. After the immersion is completed, it is washed with distilled water, dried, crushed, added into polyethylene glycol and polypropylene, and melt-spinned to obtain modified polypropylene fiber.

[0021] Furthermore, the weight ratio of polypropylene fiber, polyethylene glycol and polypropylene in the modified polypropylene fiber is 1:(0.8-1.2):(1-1.2).

[0022] The preparation method of the crack-resistant concrete of the present invention is:

[0023] Mix cement, water and anti-cracking agent, then add sand, fly ash, water reducing agent and slag powder in sequence, stir and mix to obtain crack-resistant concrete.

[0024] The present invention provides a construction method for a large-area anti-cracking ground, comprising the following steps:

[0025] (1) Base treatment: Before construction, calculate the settlement of the construction site, backfill and compact it to different degrees;

[0026] (2) Construction of cushion layer: pour a 5-8 cm thick concrete cushion layer on the base layer to ensure the surface level of the concrete cushion layer;

[0027] (3) Processing and installation of steel bars, and production and installation of formwork;

[0028] (4) pouring concrete, using a delivery pump to push the concrete from one end to the other end in parallel, pouring the above-obtained anti-cracking concrete in place at one time and vibrating it in time;

[0029] (5) Vibration leveling machine leveling: Use a vibration leveling machine to level the concrete surface;

[0030] (6) Concrete curing: After the crack-resistant concrete has initially set, cover the top of the ground with a wet cloth and spray water regularly to maintain it.

[0031] The present invention has the following beneficial effects:

[0032] (1) In the present invention, polyformaldehyde, polyethylene glycol, phenol, etc. are used to modify peanut shells. The chemical bonds of peanut shells are broken and degraded to varying degrees during the peanut shell phenol liquefaction reaction, and then react with polyethylene glycol and phenol to introduce hydroxyl groups, making them have good hydrophilic properties. At the same time, they contain abundant phenolic hydroxyl groups, which react with formaldehyde to make them have the properties of an adhesive, thereby improving the bonding force between them and the components in concrete. When the modified peanut shells prepared by this method are added to concrete, the cohesion of the concrete can be improved, thereby improving the crack resistance of the concrete.

[0033] (2) In the modification method of the polypropylene fiber of the present invention, the surface of the polypropylene fiber is etched with a sulfuric acid solution to increase its surface roughness, which can increase the bonding strength with other components when used in concrete; at the same time, the oxidizing property of sulfuric acid is used to oxidize the fiber surface, and polyethylene glycol is added to introduce hydroxyl groups, so that the surface of the polypropylene fiber has a certain hydrophilicity, which is beneficial to its dispersion in the concrete material and further enhances the bonding strength inside the concrete.

[0034] (3) In the crack-resistant concrete of the present invention, the various components cooperate with each other and work synergistically, which can better control the shrinkage and deformation of the concrete, improve the compressive and flexural strength of the concrete, and reduce cracks caused by the properties of the concrete itself during use. The concrete is suitable for paving large areas and will not be damaged after paving. DETAILED DESCRIPTION

[0035] The present invention is further explained below in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent modifications to the present invention by those skilled in the art all fall within the scope of protection of the claims of this application.

[0036] Example 1

[0037] Preparation of crack-resistant concrete

[0038] (1) Preparation of modified peanut shells: 20 kg of peanut shells and 1.6 kg of corn stalks were crushed, mixed, and placed in a reaction container. Then, 0.2 kg of paraformaldehyde, 4 kg of polyethylene glycol, 12 kg of phenol, and 12.4 kg of 37% hydrochloric acid solution were added in sequence, and the mixture was stirred continuously and heated to 100° C. The mixture was kept stirred at 100° C. for 1.5 h, then cooled to 70° C., 18 kg of 35% sodium hydroxide solution was added dropwise, and the mixture was cooled to room temperature to obtain modified peanut shells.

[0039] (2) Preparation of modified polypropylene fiber: 15 kg of dried polypropylene fiber was soaked in a 70% sulfuric acid solution for 1.5 h. After soaking, it was washed with distilled water, dried, crushed, and added to 18 kg of polyethylene glycol and 15 kg of polypropylene for melt spinning to obtain modified polypropylene fiber.

[0040] (3) Concrete preparation: 150 kg of cement, 70 kg of water, 8 kg of modified peanut shells, 3 kg of steel fiber, and 9 kg of modified polypropylene fiber were mixed, and then 80 kg of sand, 25 kg of fly ash, 5 kg of water reducing agent, and 15 kg of slag powder were added in sequence. After stirring and mixing, crack-resistant concrete was obtained.

[0041] Large area ground construction

[0042] (1) Base treatment: Before construction, calculate the settlement of the construction site, backfill and compact it to different degrees;

[0043] (2) Construction of cushion layer: pour a 5 cm thick concrete cushion layer on the base layer to ensure the surface level of the concrete cushion layer;

[0044] (3) Processing and installation of steel bars, and production and installation of formwork;

[0045] (4) pouring concrete, using a delivery pump to push the concrete from one end to the other end in parallel, pouring the above-obtained anti-cracking concrete in place at one time and vibrating it in time;

[0046] (5) Vibration leveling machine leveling: Use a vibration leveling machine to level the concrete surface;

[0047] (6) Concrete curing: After the crack-resistant concrete has initially set, cover the top of the ground with a wet cloth and spray water regularly to maintain it.

[0048] Example 2 Preparation of crack-resistant concrete

[0049] Preparation of modified peanut shells: Take 20kg of peanut shells and 1kg of corn stalks, crush them, mix them, and place them in a reaction container. Then add 0.24kg of polyformaldehyde, 3kg of polyethylene glycol, 14kg of phenol, and 9kg of 35% hydrochloric acid solution in sequence. Stir continuously and heat to 120°C. Keep stirring at 120°C for 1h, then cool to 80°C, add 17kg of 40% sodium hydroxide solution dropwise, and cool to room temperature to obtain modified peanut shells.

[0050] Preparation of modified polypropylene fiber: 15 kg of dry polypropylene fiber was soaked in a 60% sulfuric acid solution for 2 hours. After soaking, it was washed with distilled water, dried, crushed, and added to 12 kg of polyethylene glycol and 18 kg of polypropylene for melt spinning to obtain modified polypropylene fiber.

[0051] Concrete preparation: Mix 120kg of cement, 80kg of water, 12kg of modified peanut shells, 2.5kg of steel fiber, and 12.5kg of modified polypropylene fiber, then add 100kg of sand, 45kg of fly ash, 10kg of water reducer, and 12kg of slag powder in sequence, stir and mix to obtain crack-resistant concrete.

[0052] Large area ground construction

[0053] (1) Base treatment: Before construction, calculate the settlement of the construction site, backfill and compact it to different degrees;

[0054] (2) Construction of cushion layer: pour 8 cm thick concrete cushion layer on the base layer to ensure the surface level of the concrete cushion layer;

[0055] (3) Processing and installation of steel bars, and production and installation of formwork;

[0056] (4) pouring concrete, using a delivery pump to push the concrete from one end to the other end in parallel, pouring the above-obtained anti-cracking concrete in place at one time and vibrating it in time;

[0057] (5) Vibration leveling machine leveling: Use a vibration leveling machine to level the concrete surface;

[0058] (6) Concrete curing: After the crack-resistant concrete has initially set, cover the top of the ground with a wet cloth and spray water regularly to maintain it.

[0059] Example 3 Preparation of crack-resistant concrete

[0060] Preparation of modified peanut shells: Take 20kg of peanut shells and 1.2kg of corn stalks, crush them, mix them, and place them in a reaction container. Then add 0.22kg of polyformaldehyde, 4kg of polyethylene glycol, 13kg of phenol, and 10kg of 36% hydrochloric acid solution in sequence, stir continuously and heat to 120°C, keep stirring at 120°C for 1h, then cool to 80°C, add 17kg of 38% sodium hydroxide solution dropwise, and cool to room temperature to obtain modified peanut shells.

[0061] Preparation of modified polypropylene fiber: 15 kg of dried polypropylene fiber was soaked in a 65% sulfuric acid solution for 2 hours. After soaking, it was washed with distilled water, dried, crushed, and added to 15 kg of polyethylene glycol and 15 kg of polypropylene for melt spinning to obtain modified polypropylene fiber.

[0062] Concrete preparation: Mix 130kg of cement, 75kg of water, 10kg of modified peanut shells, 3kg of steel fiber, and 12kg of modified polypropylene fiber, then add 90kg of sand, 35kg of fly ash, 8kg of water reducer, and 13kg of slag powder in sequence, stir and mix to obtain crack-resistant concrete.

[0063] Large area ground construction

[0064] (1) Base treatment: Before construction, calculate the settlement of the construction site, backfill and compact it to different degrees;

[0065] (2) Construction of cushion layer: pour a 6 cm thick concrete cushion layer on the base layer to ensure the surface level of the concrete cushion layer;

[0066] (3) Processing and installation of steel bars, and production and installation of formwork;

[0067] (4) pouring concrete, using a delivery pump to push the concrete from one end to the other end in parallel, pouring the above-obtained anti-cracking concrete in place at one time and vibrating it in time;

[0068] (5) Vibration leveling machine leveling: Use a vibration leveling machine to level the concrete surface;

[0069] (6) Concrete curing: After the crack-resistant concrete has initially set, cover the top of the ground with a wet cloth and spray water regularly to maintain it.

[0070] Comparative Example 1 Preparation of crack-resistant concrete

[0071] Preparation of modified peanut shells: Take 20 kg of peanut shells, crush them, put them in a reaction container, then add 13 kg of phenol and 10 kg of 36% hydrochloric acid solution in turn, stir continuously and heat to 120°C, keep stirring at 120°C for 1 hour, then cool to 80°C, add 17 kg of 38% sodium hydroxide solution dropwise, cool to room temperature, and obtain modified peanut shells.

[0072] Concrete preparation: Mix 130kg of cement, 75kg of water, 10kg of modified peanut shells, 3kg of steel fiber, and 15kg of polypropylene fiber, then add 90kg of sand, 35kg of fly ash, 8kg of water reducer, and 13kg of slag powder in sequence, stir and mix to obtain crack-resistant concrete.

[0073] Large area ground construction

[0074] (1) Base treatment: Before construction, calculate the settlement of the construction site, backfill and compact it to different degrees;

[0075] (2) Construction of cushion layer: pour a 6 cm thick concrete cushion layer on the base layer to ensure the surface level of the concrete cushion layer;

[0076] (3) Processing and installation of steel bars, and production and installation of formwork;

[0077] (4) pouring concrete, using a delivery pump to push the concrete from one end to the other end in parallel, pouring the above-obtained anti-cracking concrete in place at one time and vibrating it in time;

[0078] (5) Vibration leveling machine leveling: Use a vibration leveling machine to level the concrete surface;

[0079] (6) Concrete curing: After the crack-resistant concrete has initially set, cover the top of the ground with a wet cloth and spray water regularly to maintain it.

[0080] Comparative Example 2 Preparation of crack-resistant concrete

[0081] Preparation of modified polypropylene fiber: 15 kg of dried polypropylene fiber was soaked in a 65% sulfuric acid solution for 2 hours. After soaking, it was washed with distilled water, dried, crushed, and added to 15 kg of polyethylene glycol and 15 kg of polypropylene for melt spinning to obtain modified polypropylene fiber.

[0082] Concrete preparation: Mix 130kg of cement, 75kg of water, and 15kg of modified polypropylene fiber, then add 90kg of sand, 35kg of fly ash, 8kg of water reducer, and 13kg of slag powder in sequence, stir and mix to obtain crack-resistant concrete.

[0083] Large area ground construction

[0084] (1) Base treatment: Before construction, calculate the settlement of the construction site, backfill and compact it to different degrees;

[0085] (2) Construction of cushion layer: pour a 6 cm thick concrete cushion layer on the base layer to ensure the surface level of the concrete cushion layer;

[0086] (3) Processing and installation of steel bars, and production and installation of formwork;

[0087] (4) pouring concrete, using a delivery pump to push the concrete from one end to the other end in parallel, pouring the above-obtained anti-cracking concrete in place at one time and vibrating it in time;

[0088] (5) Vibration leveling machine leveling: Use a vibration leveling machine to level the concrete surface;

[0089] (6) Concrete curing: After the crack-resistant concrete has initially set, cover the top of the ground with a wet cloth and spray water regularly to maintain it.

[0090] Comparative Example 3 Preparation of crack-resistant concrete

[0091] Preparation of modified polypropylene fiber: 15 kg of dried polypropylene fiber was soaked in a 65% sulfuric acid solution for 2 hours. After soaking, it was washed with distilled water, dried, crushed, and added to 15 kg of polypropylene solution for melt spinning to obtain modified polypropylene fiber.

[0092] Concrete preparation: Mix 130kg of cement, 75kg of water, 10kg of peanut shell powder, and 12kg of modified polypropylene fiber, then add 90kg of sand, 35kg of fly ash, 8kg of water reducer, and 13kg of slag powder in sequence, stir and mix to obtain crack-resistant concrete.

[0093] Large area ground construction

[0094] (1) Base treatment: Before construction, calculate the settlement of the construction site, backfill and compact it to different degrees;

[0095] (2) Construction of cushion layer: pour a 6 cm thick concrete cushion layer on the base layer to ensure the surface level of the concrete cushion layer;

[0096] (3) Processing and installation of steel bars, and production and installation of formwork;

[0097] (4) pouring concrete, using a delivery pump to push the concrete from one end to the other end in parallel, pouring the above-obtained anti-cracking concrete in place at one time and vibrating it in time;

[0098] (5) Vibration leveling machine leveling: Use a vibration leveling machine to level the concrete surface;

[0099] (6) Concrete curing: After the crack-resistant concrete has initially set, cover the top of the ground with a wet cloth and spray water regularly to maintain it.

[0100] Test example

[0101] 1. Referring to the relevant provisions of "Anti-cracking and anti-seepage composite materials for concrete", the crack reduction coefficient in the early crack resistance of the concrete prepared according to the method described in Examples 1-3 and Comparative Examples 1-3 was determined.

[0102] 2. Referring to the Standard Test Method for Ordinary Mechanical Properties of Ordinary Concrete, the compressive strength and flexural strength of the concrete prepared according to the methods described in Examples 1-3 and Comparative Examples 1-3 were measured.

[0103] 3. According to the standard of "Mortar and Concrete Shrinkage Reducing Agent", the shrinkage reduction rate of the concrete prepared according to the method described in Examples 1-3 and Comparative Examples 1-3 was measured for 28 days and 60 days.

[0104] Table 1 Test results of various concrete performance indicators

[0105]

[0106] From the results in Table 1, it can be seen that the concrete of Examples 1-3 prepared according to the method of the present invention is significantly better than that of Comparative Examples 1-3 in terms of concrete crack reduction coefficient, compressive and flexural strength, reduction rate, splitting tensile strength, etc. It can be seen that the concrete prepared by the present invention has more excellent crack resistance, can better control the shrinkage deformation of concrete, and can effectively avoid cracks caused by the properties of the concrete itself when used for large-area floor paving. The modified peanut shells and modified polypropylene fibers are added to the present invention, which can effectively improve the cohesion inside the concrete and improve the crack resistance of the concrete. Comparative Example 1 peanut shells are modified in different ways and polypropylene fibers are not modified; Comparative Example 2 has no modified peanut shells; Comparative Example 3 peanut shells are not modified, and polypropylene fibers are modified in different ways. Its various indicators are worse than those of the embodiments. It can be seen that modified peanut shells and modified polypropylene fibers have a significant effect on improving the crack resistance of concrete.

Claims

1. A large area anti-crack floor, characterized in that: The anti-crack concrete is used for pouring during the construction. The anti-crack concrete contains the following components in parts by weight: 120-150 parts of cement, 80-100 parts of sand, 25-45 parts of fly ash, 5-10 parts of water reducer, 12-15 parts of slag powder, 20-27 parts of anti-cracking agent, 70-80 parts of water; The anti-cracking agent contains 8-12 parts of modified peanut shells and 12-15 parts of composite fibers; the composite fibers contain steel fibers and modified polypropylene fibers in a weight ratio of 1:(3-5); The preparation method of the modified polypropylene fiber is as follows: the dried polypropylene fiber is placed in a sulfuric acid solution with a mass fraction of 60-70% and soaked for 1.5-2 hours, and after soaking, it is washed with distilled water, dried, crushed, and then added to polyethylene glycol and polypropylene for melt spinning to obtain the modified polypropylene fiber; the weight ratio of the polypropylene fiber, polyethylene glycol, and polypropylene is 1: (0.8-1.2): (1-1.2); The preparation method of the modified peanut shell is as follows: peanut shell and corn stalk are crushed, paraformaldehyde, polyethylene glycol, phenol and hydrochloric acid are added in sequence, the mixture is stirred continuously and heated to 100-120° C., the mixture is kept warm and stirred at 100-120° C. for 1-1.5 hours, then cooled to 70-80° C., sodium hydroxide is added dropwise, and the mixture is cooled to room temperature to obtain the modified peanut shell; the amount of corn stalk added is 5-8% of the weight of the peanut shell, the amount of paraformaldehyde added is 1-1.2% of the weight of the peanut shell, the amount of polyethylene glycol added is 15-20% of the weight of the peanut shell, the amount of phenol added is 60-70% of the weight of the peanut shell, the amount of hydrochloric acid added is 45-65% of the weight of the peanut shell, and the amount of sodium hydroxide added is 85-90% of the weight of the peanut shell; the mass fraction of the hydrochloric acid is 35-37%, and the mass fraction of the sodium hydroxide is 35-40%.

2. The large-area anti-crack floor as claimed in claim 1, characterized in that: The preparation method of the crack-resistant concrete is: Mix cement, water and anti-cracking agent, then add sand, fly ash, water reducing agent and slag powder in sequence, stir and mix to obtain crack-resistant concrete.

3. A construction method for large-area anti-cracking ground according to claim 1 or 2, characterized in that: The following steps are involved: (1) Base treatment: calculate the settlement of the construction site before construction, and backfill and compact it to different degrees; (2) Construction of cushion layer: pour a 5-8 cm thick concrete cushion layer on the base layer to ensure the surface level of the concrete cushion layer; (3) Processing and installation of steel bars, and production and installation of formwork; (4) pouring concrete, using a delivery pump to push the concrete in parallel from one end to the other end, pouring the anti-cracking concrete according to any one of claims 1 to 2, pouring it in place at one time and vibrating it in time; (5) Vibration leveling machine leveling: Use a vibration leveling machine to level the concrete surface; (6) Concrete maintenance: After the crack-resistant concrete has initially set, cover the top of the ground with a wet cloth and spray water regularly to maintain it.

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