The construction period of the concrete main structure shall not be less than 5 days / floor.
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.
The determination and control of the construction period must follow the principles of safety first, quality first, technical feasibility, economic rationality and environmental protection.
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.
Source: the construction of Dongguan Municipal Bureau of housing and urban rural development and the main building management body of Guangdong Province shall not be less than 5 days / floor.
(1) Ensure the quality inspection of raw materials.
The supervision unit shall carry out 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 side-by-side and parallel inspection.
The testing unit shall strengthen the internal management of concrete sample receiving and testing, and no fraud is allowed II.
Strictly control the thickness of floor slab and the thickness of reinforcement protective layer.
The supervision unit shall patrol the curing of concrete..
IV.
3.
The supervision unit shall do a good job in the whole process of concrete pouring at important parts.
Scientifically and reasonably arrange the construction period of the project, reasonably determine and effectively control the construction period is an important content of project management, and the “red line” must be firmly established Awareness and ensure the quality and safety of the project.
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.
The post cast strip and construction joint treatment method shall meet the specification requirements, and the pouring shall be carried out according to the time required by the design and specification.
Observe the key points of concrete pouring and vibration construction of wall, column, beam and slab.
2.
All enterprises shall ensure that the common mix proportion is verified at least once a quarter.
strengthen the production quality management of ready mixed concrete.
They shall strengthen the raw material inspection, divide the inspection batches in strict accordance with the requirements of specifications and standards, and inspect the performance indicators of relevant projects to ensure that they must be inspected before use, It is forbidden to use unqualified raw materials Strictly control the concrete mix proportion.
Attached original: Notice on strengthening the concrete quality management of construction projects.
After concrete pouring, it shall be ensured that the concrete has sufficient curing time with formwork, and moisture conservation shall be carried out in time.
Ensure the support and support And prevent cracks in the 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 dismantle it at will and not to return to the top after demolition.
If it is confirmed by all parties of the project that it is necessary to implement it according to 5 days / floor, The construction scheme to ensure the quality and safety of the project shall be formulated and implemented only after being demonstrated and approved by experts.
At the connecting parts of wall, slab, beam and column, concrete with high strength grade shall be poured first, and then concrete with low strength grade shall be poured after the concrete with high strength grade is initially set.
III.
The exposed surface of foundation mass concrete shall be covered for curing, and reliable temperature control measures shall be taken during concrete curing, and the concrete curing method shall comply with relevant regulations Code for construction of concrete structure engineering stipulates that during the curing of cast-in-situ floor slab, when the strength is less than 10MPa, heavy objects shall not be lifted or stacked on the cast-in-situ floor slab.
The construction unit shall formulate a 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 to ensure that the concrete can be poured in time after passing the mobilization inspection.
All ready mixed concrete enterprises shall strengthen the delivery inspection of ready mixed concrete, provide the delivery note and delivery quality certificate of ready mixed concrete according to the regulations, and ensure the quality of ready mixed concrete products.
No water shall be added within 24 hours after the completion of floor slab pouring and tamping Loading.
When the concrete strength grades of wall, column and beam and slab are different, effective interception measures shall be taken to prevent concrete pouring of high and low grade concrete.
The construction unit is responsible for the determination and control of the construction period of the construction project and shall not arbitrarily reduce the construction period.
(III) Strengthen concrete curing.
When the standby common mix proportion is used, It shall be verified or adjusted during commissioning.
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, and 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.
strengthen the quality control of concrete construction process (I) Make preparations before concrete pouring.
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.
On August 27, Dongguan Municipal Bureau of housing and urban rural development issued a notice on strengthening the concrete quality management of construction projects.
The delivery acceptance shall focus on the confirmation of concrete category, quantity and mix proportion, mixing time, mobilization time and unloading time of mixer truck, and concrete collapse Main contents such as the measurement of fall and expansion.
(III) Strengthen the management of concrete delivery and transportation.
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 strictly comply with relevant laws, regulations and technical standards Organize production.
The construction Contractor shall reasonably arrange the schedule and carry out the construction in strict accordance with the design documents and construction technical quality standards and specifications.
Before transportation, they shall fully understand the conditions of roads, traffic and construction, and for midway transportation If the delivery 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 meets the design requirements.
(IV) standardize the concrete supply management.
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.
It is strictly prohibited to add water during concrete pumping and pouring.
All ready mixed concrete production enterprises shall carry out mix proportion design in strict accordance with the national standards and supply contracts, and according to the concrete strength grade, durability and working environment requirements to ensure that the actual production mix proportion is consistent with the mix proportion report.
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.
(II) strengthen the management of the concrete pouring process, and the construction unit shall strictly follow the prevention and control manual of common quality problems of construction projects in Dongguan Dongguan construction project quality standardization manual It is required to strengthen the concrete construction management of important parts and carry out the whole process quality control: 1.
The delivery acceptance shall be carried out in strict accordance with the supply and demand contract in cooperation with the user.
The curing time and thermal insulation coverage measures shall comply with relevant regulations.
It is strictly prohibited to add water during the transportation of ready mixed concrete, and the transportation time shall be reasonably controlled.
The construction unit shall implement the primary responsibility, scientifically and reasonably determine the construction period and cost of the project.
Clear: the construction period of concrete main structure shall not be less than 5 days / layer.
All ready mixed concrete production enterprises shall strictly implement the supply account management, strengthen the source control, and shall not sell commercial concrete to illegal construction projects that fail to go through the construction permit or supervision and registration procedures as required.
9) , 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: first, implement the main project quality responsibilities of all parties involved in the construction, and all parties involved in the construction shall strictly implement the main project quality responsibilities, 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.
4.
Once found, they will be seriously dealt with.
