The construction unit shall implement the primary responsibility, scientifically and reasonably determine the construction period and cost of the project
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The supervision unit shall conduct patrol inspection on the process of acceptance of ready mixed concrete by the construction unit, strengthen the supervision of concrete construction process, and strictly implement the responsibilities of on-site and parallel inspection
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Before transportation, the road, traffic and construction conditions shall be fully understood
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Ensure the stability of support and support and prevent cracks in cast-in-situ floor slab; The support system of the post cast strip must be set separately and painted with red eye-catching paint to remind the operators not to remove it at will and it is strictly prohibited to return to the top after removal（ 2） Strengthen the management of concrete pouring process
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At the joint of wall and slab, beam and column, the concrete with high strength grade shall be poured first, and then the concrete with low strength grade shall be poured after the concrete with high strength grade is initially set
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The treatment method of post cast strip and construction joint shall meet the specification requirements, and the pouring shall be carried out according to the time required by the design and specification
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The delivery acceptance shall be carried out in strict accordance with the supply and demand contract and in cooperation with the user
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4
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The testing unit shall strengthen the internal management of concrete specimen receiving and testing, and fraud is strictly prohibited
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All ready mixed concrete enterprises shall strengthen the delivery inspection of ready mixed concrete, and provide the delivery note and delivery quality certificate of ready mixed concrete as required to ensure the quality of ready mixed concrete products
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The curing time and thermal insulation coverage measures shall comply with relevant regulations.
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For the case that the midway transportation time is more than 90 minutes, effective technical measures shall be taken, and the test verification shall be carried out to ensure that the concrete performance can meet the design requirements
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On August 27, Dongguan Municipal Bureau of housing and urban rural development issued a notice on strengthening the quality management of concrete in construction projects
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The construction unit shall formulate the concrete construction scheme before concrete pouring, jointly determine the position of post pouring belt and construction joint with the design unit, clarify the pouring time of post pouring belt concrete and the treatment method of post pouring belt and construction joint, and make technical disclosure, Ensure that the concrete can be poured in time after passing the mobilization inspection
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Previously, Shenzhen issued a notice on Further Strengthening the concrete quality management of construction projects, which made it clear that in principle, the construction period of concrete main structure shall not be less than 6 days / layer, and those less than or equal to 5 days / layer shall be demonstrated and approved by experts, and less than 4 days / layer is strictly prohibited
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The floor slab shall not be loaded within 24 hours after pouring and tamping
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9), and in combination with the actual situation of our city, the notice on strengthening the construction quality management of concrete structures of construction projects is as follows: I Implement the main project quality responsibilities of all parties involved in the construction
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Once found, they will be seriously dealt with
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The design unit shall improve the design quality of concrete structure engineering and formulate structural measures in strict accordance with the prevention and control requirements of common quality problems
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All ready mixed concrete production enterprises shall carry out mix proportion design in strict accordance with national standards and supply contracts, and according to the concrete strength grade, durability and working environment requirements, so as to ensure that the actual mix proportion is consistent with the mix proportion report
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The delivery acceptance shall mainly include the confirmation of concrete category, quantity and mix proportion, the confirmation of mixing time, mobilization time and unloading time of mixer truck, and the measurement of concrete slump and expansion（ 4） Standardize concrete supply management
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All parks, town (street) housing and urban rural development bureaus and relevant units (enterprises): in order to prevent quality and safety production accidents caused by the concrete strength of the main structure failing to meet the design requirements of the project under construction, and reduce the quality problems such as floor cracking and thickness failing to meet the design requirements, Improve the safety performance of buildings, further strengthen the construction quality management of concrete structures of housing construction projects in our city, and ensure the quality and structural safety of housing construction projects, In accordance with the construction law, the regulations on the quality management of construction projects, the regulations on the safety production management of construction projects, the notice of the Ministry of housing and urban rural development on implementing the primary responsibility for the project quality of construction units (JZG [2020] No
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When the standby common mix proportion is used, it shall be verified or adjusted during the use process
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Ready mixed concrete production enterprises shall be responsible for the production quality of ready mixed concrete, further improve the quality management system, product quality assurance system and product quality tracking system, and organize production in strict accordance with relevant laws, regulations and technical standards（ 1） Ensure the quality inspection of raw materials, and all ready mixed concrete production enterprises shall strengthen the mobilization inspection and quality control of raw materials, establish and improve the raw material procurement management system and raw material use account, so as to realize the traceability of the use process of raw materials
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2、 Scientifically and reasonably arrange the construction period, reasonably determine and effectively control the construction period is an important content of project management
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It is strictly prohibited to add water during concrete pumping and pouring
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Observe the key points of wall column, beam slab concrete pouring and vibration construction
Strictly control the thickness of floor slab and the thickness of reinforcement protective layer
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The inspection of raw materials shall be strengthened, the inspection batches shall be divided in strict accordance with the requirements of specifications and standards, and the performance indexes of relevant items shall be inspected to ensure that they must be inspected before use, and the use of unqualified raw materials is prohibited（ 2） Strictly control the concrete mix proportion
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If it is confirmed by all parties to the project that it needs to be implemented according to 5 days / layer, a construction scheme to ensure project quality and safety shall be formulated and implemented after being demonstrated and approved by experts
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Attached original: Notice on strengthening the concrete quality management of construction projects
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4、 Strengthen the quality control of concrete construction process (I) make preparations before concrete pouring
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Each enterprise shall ensure that the common mix proportion is verified at least once a quarter
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Cushion blocks, slab negative reinforcement support and concealed pipelines shall be set according to the specification requirements to ensure the thickness of floor slab and the effective height of floor reinforcement
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In case of significant changes in the variety and quality of raw materials or special requirements for concrete performance, the mix proportion design shall be carried out again（ 3） Strengthen the management of concrete delivery and transportation
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The construction period of concrete main structure shall not be less than 5 days / layer
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If it is confirmed by all parties to the project that it needs to be implemented according to 5 days / layer, a construction scheme to ensure project quality and safety shall be formulated and implemented after being demonstrated and approved by experts
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The construction contractor shall reasonably arrange the schedule and carry out construction in strict accordance with the design documents and construction technical quality standards and specifications
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The construction unit shall strengthen the concrete construction management of important parts and carry out the whole process quality control in strict accordance with the requirements of the prevention and control manual of common construction engineering quality problems in Dongguan and the quality standardization Manual of Construction Engineering in Dongguan: 1
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The construction unit shall be responsible for the determination and control of the construction period, and shall not arbitrarily reduce the construction period
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The determination and control of construction period must follow the principles of safety first, quality priority, technical feasibility, economic rationality and environmental protection
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Each responsible party involved in the construction shall strictly implement the main responsibility of project quality, establish and improve the quality assurance system and mechanism, strengthen the process management of project quality, improve the quality awareness of all parties involved in the construction, and ensure the project quality and structural safety
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It is strictly prohibited to add water during the transportation of ready mixed concrete, and the transportation time shall be reasonably controlled
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The copyright of Dongguan Municipal Bureau of housing and urban rural development belongs to the original author
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All ready mixed concrete production enterprises shall strictly implement supply account management, strengthen source control, and shall not sell commercial concrete to illegal construction projects that fail to go through construction permit or supervision and registration procedures as required
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It is strictly prohibited to rush the construction period and speed up the progress blindly, and shall not force other participating units of the project to simplify the process and reduce the quality standard
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We must firmly establish the awareness of “red line” to ensure project quality and safety
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When the strength grade of wall, column, beam and slab concrete is different, effective interception measures shall be taken to prevent mixed pouring of high and low grade concrete
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3
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Clear: the construction period of concrete main structure shall not be less than 5 days / layer
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After concrete pouring, ensure that the concrete has sufficient curing time with formwork, and carry out moisturizing curing in time
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3、 Strengthen the production quality management of ready mixed concrete
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The supervision unit shall do a good job in the whole process of concrete pouring at important parts（ 3） Strengthen concrete curing
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