Large-area seamless concrete construction method

Abstract

The invention discloses a large-area seamless concrete construction method which comprises the following steps: S1, dividing a pouring area according to a preset partition line to obtain a plurality of sub-areas; s2, carrying out bin block division on the sub-regions, carrying out concrete pouring on a plurality of bin blocks according to a bin jumping method, and then connecting the plurality of bin blocks into a whole until the concrete pouring of the whole sub-regions is completed; s3, the sub-areas are connected into a whole till concrete pouring of the whole pouring area is completed; in the construction process of the step S2, a concrete pouring method for each warehouse block comprises the steps that S21, concrete slope layered pouring is conducted on the warehouse blocks; s22, surface finishing is conducted on the uppermost layer of concrete; s23, the poured concrete is cured; the concrete is solidified; in the construction process of the steps S21-S23, temperature measurement and control and crack prevention and control are carried out on the concrete; according to the scheme, temperature measurement and control and crack prevention and control are carried out on the concrete by adopting a warehouse jumping method, so that the possibility of crack generation is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of concrete construction, and in particular to a large-area seamless concrete construction method. Background Art

[0002] During the large-scale concrete pouring construction process, there are differences in the distribution of cement hydration heat, which causes uneven shrinkage of the concrete and causes cracks inside the concrete; the larger the volume of concrete poured, the more significant the temperature cracks caused by cement hydration heat; temperature cracks in large-volume concrete are very dangerous, not only affecting the integrity of the concrete, but also causing stress redistribution, significantly changing the stress state of the structure, reducing the bearing capacity of the structure, and in severe cases may cause partial or even overall damage to the structure, threatening the safety and durability of the structure.

[0003] Cracks in concrete will significantly reduce the concrete's impermeability, and moisture in the air and environment will penetrate into the concrete, causing steel corrosion, thereby reducing the structure's bearing capacity and durability. Secondly, the cost of construction measures to prevent cracks accounts for about 3% of the project cost, but the cost of crack treatment is as high as 5% to 10%. Therefore, formulating reasonable temperature control and crack prevention and control measures and applying them properly will have a positive impact on the achievement of the economic and technical indicators of the entire project.

[0004] At present, in order to overcome harmful cracks caused by temperature, shrinkage and other reasons, post-cast joints are often set during the construction of cast-in-place reinforced concrete structures. However, if a large number of post-cast joints are set for large-volume concrete, the construction progress will be seriously slowed down. At the same time, the installation of post-cast joints will cause the basement to be in a leaking state all the time, and it is also very easy to crack and seep after being closed. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides a large-area seamless concrete construction method, which solves the problem that cracks are easily generated during the large-area concrete pouring construction process.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is:

[0007] A large-area seamless concrete construction method is provided, which comprises the following steps:

[0008] S1: Divide the casting area according to the preset partition lines and obtain several sub-areas;

[0009] S2: Divide the sub-area into blocks, and pour concrete on several blocks according to the skipping method, and then connect several blocks into a whole until the concrete pouring of the entire sub-area is completed;

[0010] S3: Connect several sub-areas into a whole until the concrete pouring of the entire pouring area is completed;

[0011] During the construction process of step S2, the method for pouring concrete for each bin block includes:

[0012] S21: pouring concrete on the silo block in layers on the inclined surface;

[0013] S22: Finishing the top layer of concrete;

[0014] S23: Curing the poured concrete until the concrete solidifies;

[0015] During the construction process of steps S21-S23, the temperature of the concrete is measured and controlled, and cracks are prevented and controlled.

[0016] Furthermore, the temperature measurement and control method includes:

[0017] A1: When pouring concrete on the silo block in layers, a number of temperature sensors are evenly buried in each layer of concrete;

[0018] A2: Use several temperature sensors to monitor the temperature of each temperature measuring point during concrete pouring and the temperature change after concrete pouring;

[0019] A3: Use temperature control measures to control the mold entry temperature and subsequent temperature changes to remain within the preset temperature range.

[0020] Furthermore, the method of embedding the temperature sensor in concrete includes:

[0021] A11: Fix the temperature sensor at one end of the support rod and perform heat insulation between the temperature sensor and the support rod;

[0022] A12: Tie the temperature measuring wire of the temperature sensor to the support rod, and lead the temperature measuring wire along the extension direction of the support rod to the other end of the support rod;

[0023] A13: When pouring concrete in layers on a slope, implant the support rod into the concrete until the temperature sensor reaches the measuring point.

[0024] Furthermore, the temperature control measures in step A3 include:

[0025] A31: Before pouring concrete slopes in layers, determine the construction date and construction period based on recent weather conditions;

[0026] A32: Adjust the temperature of the water added during concrete mixing until the temperature entering the mold meets the preset temperature range;

[0027] A33: Reduce the hydration heat temperature rise of concrete by adjusting the mix ratio of concrete.

[0028] Furthermore, the concrete includes gel material, fine aggregate, coarse aggregate, concrete admixture and water, and the gel material includes cement, fly ash, slag powder and expansion agent; the method for adjusting the concrete mix ratio includes: the mass ratio of water to gel material is not greater than 0.45, and the water content is not greater than 170kg / m 3 , the mass ratio of coarse aggregate is 38%-45%, the slump of concrete is not more than 180mm, and the adiabatic temperature rise of concrete is not more than 50℃.

[0029] Furthermore, the method of crack prevention and control includes:

[0030] B1: Control the thickness of each layer of concrete, and the thickness of each layer of concrete shall not exceed 450mm;

[0031] B2: During the pouring of each layer of concrete, the concrete is vibrated point by point through a number of inserted vibrating rods until the concrete is vibrated evenly and densely;

[0032] B3: Cover the poured concrete surface with aerogel insulation felt and sprinkle water on the concrete surface regularly to keep it moist.

[0033] Further, the method of vibrating concrete includes:

[0034] B21: Arrange several inserted vibrating rods in a matrix, and equip one inserted vibrating rod at the discharge port, slope angle, and slope center for vibration;

[0035] B22: After the inserted vibrator is vibrated, slowly pull it out. During the process of pulling out the inserted vibrator, the surrounding concrete automatically fills the hole left by the inserted vibrator.

[0036] B23: Use small white lines to control the concrete slab elevation and surface flatness.

[0037] Furthermore, the method for finishing the top layer of concrete in step S22 includes: flattening the top layer of concrete before initial setting, and repeatedly pressing the concrete surface until the surface aggregate sinks evenly, and the last pressing is completed before the end of water seepage.

[0038] Furthermore, the interval pouring time between skipping bins in step S2 is not less than 7 days; before several bin blocks are connected as a whole, each bin block needs to undergo 7-10 days of stress release; the interval pouring time between two adjacent sub-areas in step S3 is not less than 7 days

[0039] The beneficial effects of the present invention are:

[0040] This plan adopts the skip-bin method for compartment construction, which speeds up the construction time of the concrete structure, improves the utilization efficiency of various turnover materials, and eliminates a large number of processes such as waterproofing and formwork construction at the post-casting joint position, as well as post-casting joint concrete chiseling, garbage cleaning, and post-casting joint support, thereby reducing construction costs and construction difficulties and eliminating the hidden dangers of leakage in the later post-casting joint. At the same time, during the concrete pouring process, the concrete is temperature-controlled and cracks are prevented and controlled, and the skip-bin method is used to further improve the quality of engineering construction and reduce the possibility of cracks. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Flow chart of large area seamless concrete construction method. DETAILED DESCRIPTION

[0042] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0043] like Figure 1 As shown, the large-area seamless concrete construction method of the present scheme comprises the following steps:

[0044] S1: Divide the casting area according to the preset partition lines and obtain several sub-areas;

[0045] S2: Divide the sub-area into blocks, and pour concrete for several blocks according to the skip-bin method, and then connect the blocks into a whole until the concrete pouring of the entire sub-area is completed; the interval between skip-bin pouring is not less than 7 days; before several blocks are connected into a whole, each block needs to undergo 7-10 days of stress release, and then the blocks are connected into a whole, relying on tensile strength to resist the temperature shrinkage stress of the next stage. If the conditions such as the on-site construction site are limited, the skip-bin position can be flexibly adjusted accordingly;

[0046] S3: Connect several sub-areas into a whole until the concrete pouring of the entire pouring area is completed; the interval pouring time between two adjacent sub-areas shall not be less than 7 days.

[0047] During the construction process of step S2, the method for pouring concrete for each bin block includes:

[0048] S21: pouring concrete on the silo block in layers on the inclined surface;

[0049] S22: Finishing the top layer of concrete; specifically, it includes: scraping the top layer of concrete flat before initial setting, and repeatedly pressing the concrete surface until the surface aggregates sink evenly and are not restricted by steel bars and larger aggregates, so as to improve the surface density and reduce plastic shrinkage deformation; at the same time, the last pressing is completed before the end of bleeding, so as to better control the cracks on the concrete surface and reduce the evaporation of water on the concrete surface, so as to promote maintenance;

[0050] S23: Maintain the poured concrete until it solidifies. Specifically, when pouring concrete in windy weather, wind shields and other wind-blocking measures can be added to the work surface, and secondary concrete compaction measures can be added. When pouring concrete in rainy weather, a canopy can be set up, a reasonable construction joint location can be selected, and concrete pouring can be stopped as soon as possible. The poured concrete that has not yet hardened can be covered in time to prevent rain from eroding the concrete.

[0051] During the construction process of steps S21-S23, the temperature of the concrete is measured and controlled, and cracks are prevented and controlled.

[0052] The temperature measurement and control methods include:

[0053] A1: When pouring concrete on the silo block in layers on the slope, a number of temperature sensors are evenly buried in each layer of concrete; the temperature sensors are arranged at the surface, bottom and center temperature measuring points along the thickness direction of the concrete casting body, and the distance between the measuring points is not more than 500mm; the method of burying the temperature sensors specifically includes:

[0054] A11: Fix the temperature sensor at one end of the support rod and perform heat insulation between the temperature sensor and the support rod;

[0055] A12: Tie the temperature measuring wire of the temperature sensor to the support rod, and lead the temperature measuring wire along the extension direction of the support rod to the other end of the support rod;

[0056] A13: When pouring concrete on a slope in layers, implant the support rod into the concrete until the temperature sensor reaches the temperature measuring point. Leave the temperature measuring line at the other end of the support rod outside the concrete and cover it with a plastic bag to avoid moisture and keep it clean. The temperature of the corresponding temperature measuring point is displayed on the main display.

[0057] A2: Use several temperature sensors to monitor the temperature of each temperature measuring point during concrete pouring and the temperature change after concrete pouring; and the temperature of the concrete pouring should be measured at least twice per shift; after concrete pouring, the temperature should be measured at least 4 times per day and night;

[0058] A3: Temperature control measures are used to control the mold entry temperature and subsequent temperature changes within the preset temperature range; specific temperature control measures include:

[0059] A31: Before pouring concrete on the slope in layers, determine the construction date and time period based on recent weather conditions; concrete pouring can be preferably carried out at night;

[0060] A32: Adjust the temperature of the water added when mixing concrete until the temperature entering the mold meets the preset temperature range; when constructing in summer, add ice cubes when mixing concrete to lower the concrete temperature; and when constructing in winter, lay quilts to keep the concrete warm;

[0061] A33: By adjusting the mix ratio of concrete, the hydration heat temperature rise of concrete can be reduced; concrete includes gel material, fine aggregate, coarse aggregate, concrete admixture and water, and the gel material includes cement, fly ash, slag powder and expansion agent; the adjustment method of concrete mix ratio not only complies with the provisions of the current industry standard "Ordinary Concrete Mix Design Code" (JGJ55-2011), but also includes: the mass ratio of water to gel material is not more than 0.45, and the water content is not more than 170kg / m 3 , the mass ratio of coarse aggregate is 38%-45%, the slump of concrete is not more than 180mm, and the adiabatic temperature rise of concrete is not more than 50℃.

[0062] Since the temperature rise due to hydration heat mainly depends on the type of cement, cement dosage and heat dissipation rate, this scheme adopts low hydration heat cement to reduce the cement dosage in the concrete mix ratio. Under the condition of ensuring the strength and slump of concrete, coarse aggregate and fly ash are appropriately added to reduce the temperature rise due to hydration heat of concrete and control the final hydration heat.

[0063] The crack prevention and control methods of this program include:

[0064] B1: Control the thickness of each layer of concrete, and the thickness of each layer of concrete should not exceed 450mm; make sure that the hydration heat of the concrete is fully dissipated; when implementing, pour from one side to the other side in sequence to ensure that the upper layer of concrete is poured before the lower layer of concrete begins to set;

[0065] B2: During the pouring of each layer of concrete, the concrete is vibrated point by point through a number of inserted vibrating rods until the concrete is vibrated evenly and densely; specifically, it includes:

[0066] B21: Arrange several inserted vibrating rods in a matrix, and equip one inserted vibrating rod at the discharge port, slope angle, and slope center for vibration. Since the slump of pumped concrete is large and the concrete slope is spread over a long distance, the concrete is vibrated from the slope foot and the slope top to the slope center at the same time to ensure good bonding between the layers of concrete. The vibration time is generally controlled within 15 to 30 seconds, and the surface is no longer significantly sunk, no bubbles appear, and mortar is overflowing on the surface to avoid missed vibration, under-vibration, over-vibration, and failure to vibrate.

[0067] B22: After the inserted vibrator is vibrated, slowly pull it out, and during the process of pulling out, the surrounding concrete automatically fills the void left by the inserted vibrator; adopt the "fast insertion and slow withdrawal" method, in which fast insertion is to prevent the surface concrete from being vibrated and stratified and segregated from the underlying concrete, and slow withdrawal is to allow the concrete to fill the void caused by the withdrawal of the vibrator.

[0068] B23: Control the concrete slab elevation and surface flatness through small white lines;

[0069] B3: Cover the surface of poured concrete with aerogel insulation felt, and sprinkle water on the concrete surface regularly to keep it moist. Aerogel insulation felt has excellent thermal insulation performance and extremely low thermal conductivity, which can significantly reduce the temperature difference inside the concrete and prevent the occurrence of temperature cracks. It is light in weight but has good mechanical strength. It has excellent waterproof performance and does not absorb water, which can prevent moisture in the environment from penetrating into the concrete and protect the durability of the structure. It is resistant to high temperatures and has excellent fire resistance, which increases construction safety. It is easy to cut and install and can be flexibly applied to various complex structures. During the construction process, covering the concrete surface with aerogel insulation felt can not only ensure uniform temperature distribution, but also improve the overall quality and durability of the concrete structure.

[0070] This scheme adopts the skipping bin method for compartment construction. The principle of the skipping bin method is "jump one every other bin", that is, at least one bin block is skipped or closed for construction, and the maximum size of the block is calculated based on the external constraint crack control of the foundation concrete; the construction is carried out on the principle of both resistance and release, with resistance as the main method, and release first and then resistance; it speeds up the construction time of the concrete structure, speeds up the utilization efficiency of various turnover materials, and cancels a large number of processes such as waterproofing and formwork construction at the post-casting zone position, post-casting zone concrete chiseling, garbage cleaning, and post-casting zone support, thereby reducing construction costs and construction difficulties and eliminating the hidden dangers of leakage of the post-casting zone in the later stage; at the same time, during the pouring process of concrete, the temperature of the concrete is measured and controlled, and crack prevention and control are carried out, and the skipping bin method is used to further improve the quality of engineering construction and reduce the possibility of cracks.

Claims

1. A large-area seamless concrete construction method, It is characterized in that The following steps are involved: S1: Divide the casting area according to the preset partition lines and obtain several sub-areas; S2: Divide the sub-area into blocks, and pour concrete on several blocks according to the skipping method, and then connect several blocks into a whole until the concrete pouring of the entire sub-area is completed; S3: Connect several sub-areas into a whole until the concrete pouring of the entire pouring area is completed; During the construction process of step S2, the method for pouring concrete for each bin block includes: S21: pouring concrete on the silo block in layers on the inclined surface; S22: Finishing the top layer of concrete; S23: Curing the poured concrete until the concrete solidifies; During the construction process of steps S21-S23, the temperature of the concrete is measured and controlled, and cracks are prevented and controlled.

2. The large-area seamless concrete construction method according to claim 1, It is characterized in that The temperature measurement and control method comprises: A1: When pouring concrete on the silo block in layers, a number of temperature sensors are evenly buried in each layer of concrete; A2: Use several temperature sensors to monitor the temperature of each temperature measuring point during concrete pouring and the temperature change after concrete pouring; A3: Use temperature control measures to control the mold entry temperature and subsequent temperature changes to remain within the preset temperature range.

3. The large-area seamless concrete construction method according to claim 2, It is characterized in that The method of embedding the temperature sensor in concrete comprises: A11: Fix the temperature sensor at one end of the support rod and perform heat insulation between the temperature sensor and the support rod; A12: Tie the temperature measuring wire of the temperature sensor to the support rod, and lead the temperature measuring wire along the extension direction of the support rod to the other end of the support rod; A13: When pouring concrete in layers on a slope, implant the support rod into the concrete until the temperature sensor reaches the measuring point.

4. The large-area seamless concrete construction method according to claim 2, It is characterized in that The temperature control measures in step A3 include: A31: Before pouring concrete slopes in layers, determine the construction date and construction period based on recent weather conditions; A32: Adjust the temperature of the water added during concrete mixing until the temperature entering the mold meets the preset temperature range; A33: Reduce the hydration heat temperature rise of concrete by adjusting the mix ratio of concrete.

5. The large-area seamless concrete construction method according to claim 4, It is characterized in that The concrete comprises gel material, fine aggregate, coarse aggregate, concrete admixture and water, wherein the gel material comprises cement, fly ash, slag powder and expansion agent; the method for adjusting the concrete mix ratio comprises: the mass ratio of water to gel material is not greater than 0.45, the water content is not greater than 170kg / m 3 , the mass ratio of coarse aggregate is 38%-45%, the slump of concrete is not more than 180mm, and the adiabatic temperature rise of concrete is not more than 50℃.

6. The large-area seamless concrete construction method according to claim 1, It is characterized in that The crack prevention and control method comprises: B1: Control the thickness of each layer of concrete, and the thickness of each layer of concrete shall not exceed 450mm; B2: During the pouring of each layer of concrete, the concrete is vibrated point by point through a number of inserted vibrating rods until the concrete is vibrated evenly and densely; B3: Cover the poured concrete surface with aerogel insulation felt and sprinkle water on the concrete surface regularly to keep it moist.

7. The large-area seamless concrete construction method according to claim 1, It is characterized in that Methods of vibrating concrete include: B21: Arrange several inserted vibrating rods in a matrix, and equip one inserted vibrating rod at the discharge port, slope angle, and slope center for vibration; B22: After the inserted vibrator is vibrated, slowly pull it out. During the process of pulling out the inserted vibrator, the surrounding concrete automatically fills the hole left by the inserted vibrator. B23: Use small white lines to control the concrete slab elevation and surface flatness.

8. The large-area seamless concrete construction method according to claim 1, It is characterized in that The method for finishing the top layer of concrete in step S22 includes: scraping the top layer of concrete flat before it begins to set, and repeatedly pressing the concrete surface until the surface aggregate sinks evenly, and the last pressing is completed before the end of water seepage.

9. The large-area seamless concrete construction method according to claim 1, It is characterized in that In step S2, the interval pouring time between skip bins is not less than 7 days; before several bin blocks are connected into a whole, each bin block needs to undergo 7-10 days of stress release; in step S3, the interval pouring time between two adjacent sub-areas is not less than 7 days.

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