on Strengthening the Production and Management of Concrete Specimens for Housing Construction Projects All relevant units:
In order to further strengthen the construction quality management of construction projects in our city, effectively improve the quality of engineering entities, and standardize the quality behavior of relevant responsible subjects, According to laws, regulations, standards and regulations such as the Construction Law of the People's Republic of China, the Regulations on Quality Management of Construction Projects, the Measures for Quality Inspection and Management of Construction Projects, and the Regulations on Witness Sampling and Inspection of Housing Construction Projects and Municipal Infrastructure Projects, and in light of the actual situation of construction projects in our city. The relevant matters on strengthening the production and management of concrete test pieces are hereby notified as follows:
I. For the housing construction projects under construction in the whole city, if there are concrete structure construction parts on the site, the production and maintenance of concrete standard curing test pieces on the construction site shall be carried out in accordance with the requirements of this notice; the urban comprehensive pipe gallery projects under the supervision of the construction administrative department can be implemented by reference.
2. According to the requirements of national standards, the construction site should have the conditions for making standard concrete specimens, and the standard specimen curing room or curing box should be set up. Standard curing room or curing box can be set for unit (sub-unit) projects with a construction area of less than 10000 square meters, and curing pool can also be set on the construction site for test block curing according to the requirements of relevant national standards. For the project under construction that meets the conditions for curing the specimen with the curing pool, the curing pool shall be built indoors; the solution of the curing pool shall be the non-flowing saturated calcium hydroxide solution at 20 ± 2 ℃, and the depth of the solution shall ensure that the concrete specimen is completely immersed. For a unit (sub-unit) project with a construction area of more than 10000 square meters, a standard curing room or curing box shall be set up according to the following requirements.
(I) The setting standards of standard curing room are as follows:
1. The size of the standard curing room shall be configured according to the project scale, and the indoor area shall not be less than 6 square meters; the standard curing room is required to have the function of heat preservation and insulation, and the standard curing room shall be equipped with constant temperature and humidity devices and temperature and humidity measurement and control devices that have passed the verification/calibration. The indoor temperature shall be controlled within the range of 20 ± 2 ℃, and the indoor air relative humidity shall be greater than 95%.
２． The test piece shall be placed on the support with an interval of 10mm-20mm. The surface of the test piece shall be kept wet and shall not be directly washed by water.
(2) The standard curing box shall be a stereotyped product with a product certificate.
(3) The standard curing room or standard curing box should be calibrated regularly to ensure that the temperature and humidity control device continuously meets the requirements of the standard.
3. Requirements for the production of standard concrete curing specimens:
(1) The municipal and district construction administrative departments may use the means of information-based supervision of engineering construction, such as the technology of implanting chips into concrete specimens, the technology of real-time acquisition of concrete production and feeding data, and the technology of QR Code of building materials for inspection. The quality behavior of all parties should be included in the supervision.
(II) For the concrete specimen with standard curing, it shall stand for one to two days and nights in an environment with a temperature of 20 ± 5 ℃ and a humidity of more than 50%, and then number and remove the formwork. The number shall include the strength grade, forming date, unique identification of the test piece, etc. The formwork shall be immediately placed into a standard curing room (box) or curing pool for curing after removal.
4. Encourage construction enterprises to establish a management system for standard concrete curing specimens at construction sites, designate special persons to be responsible for it, and establish a management account for concrete specimens. The account shall record the concrete specimen number, concrete strength grade and batch represented, pouring time and location, specimen manufacturing time, inspection time, witness, supervision unit spot check record, ready-mixed concrete enterprise tracking record, temperature and humidity record, etc. Sampling, fabrication, chip implantation, marking and curing of concrete standard curing specimens shall be carried out in strict accordance with relevant technical standards and operating procedures.
5. Construction units or supervision units shall, in accordance with the provisions of the Measures for the Administration of Quality Inspection of Construction Projects and the Regulations on Witness Sampling and Inspection of Housing Construction Projects and Municipal Infrastructure Projects (Jian Jian Zi [2000] 211), Strengthen the supervision of the whole process of sampling, sample preparation, chip implantation, curing and inspection of concrete standard curing specimens to ensure the authenticity and representativeness of the specimens.
6. Concrete specimens without marks or with non-standard marks shall not be left on the construction site, and the construction unit shall not entrust or require other units such as ready-mixed concrete enterprises to make and maintain concrete specimens on its behalf.
7. Quality supervision agencies at all levels in the city shall incorporate the production and maintenance management of concrete specimens at the project site into the contents of supervision and sampling inspection, and shall clarify the relevant requirements for the management of concrete standard maintenanc e specimens to all parties involved in the project when supervising the disclosure, and find that standard curing rooms (boxes) or curing pools and concrete specimens have not been set up in accordance with the regulations. Rectification should be ordered and incorporated into credit management according to law.
8. This Circular shall enter into force as of the date of promulgation and shall be valid for five years. Notice
is hereby given.
Guangzhou Housing and Urban-Rural Development Bureau
June 24
, 2025
浙公网安备33010802003254号