On December 18, the Housing and Urban-Rural Construction Bureau of Suzhou issued the Circular on Dynamic Verification of Ready-mixed Concrete Production Enterprises in the Second Half of 2025. Where 
This verification covers the qualification of the enterprise, Laboratory management, raw materials and production quality control, mix proportion design, dust control and other key links, and the main raw materials and concrete strength of the entity were supervised and sampled. A total of 57 ready-mixed concrete enterprises in the city were sampled, including 1 in Gusu District, 2 in Industrial Park, 7 in Wuzhong District, 6 in Xiangcheng District, 5 in Wujiang District, 9 in Kunshan City, 9 in Zhangjiagang City, 11 in Changshu City and 7 in Taicang City, and 488 problems were found. For the problems found, the local housing construction department shall urge the relevant responsible enterprises to rectify and close within a time limit.
Generally speaking, most enterprises can achieve effective management in product quality control and mix ratio, and the level of dust control continues to improve. However, there are still some problems such as imperfect management system of some enterprises and weak control of raw material sources, so the quality of concrete raw materials needs to be strengthened urgently.
2. Main problems
(1) Basic information
of the enterprise: the technical personnel fail to carry out one-person-one-file management, the file information of some technical directors of the enterprise is incomplete, and there is a lack of key materials such as identity cards, job training certificates, and continuing training records; the technical directors of the enterprise are not on duty or can provide performance certificates; Some enterprises lack the post responsibilities of laboratory personnel, and there are problems of duplication and contradiction in the management system.
(II) Some standards and specifications for test management
are not updated in time, such as GB/T50082, GB/T1346, etc.; some equipment is not calibrated or the calibration is not compliant, such as the concrete vibration table is not included in the account calibration, and the vibration frequency and vertical amplitude in the calibration results do not meet the requirements of GB/T50081; Lack of environmental control, such as lack of humidity control devices in cement specific surface area laboratory and chemical analysis room, no temperature and humidity records, site environment does not meet the test requirements; incomplete test records, such as lack of soundness and setting time test process information in the original cement records; The key test operation is not standardized, for example, the sieve for fineness of fly ash is not calibrated with standard samples that meet the requirements of the standard.
(3) The quality management
system of raw materials is not perfect, for example, the acceptance system of raw materials in some enterprises follows the expired standards, which is out of line with the current requirements; The testing process is not standardized, such as the lack of testing records, no testing records of cement chloride ions and no external inspection reports, the mismatch of testing items, and the inconsistency between the main control items of coal ash and the actual testing records; Lack of on-site management, such as inconsistent identification of raw materials, lack of key information such as origin, test number and manufacturer, mixed storage of machine-made sand and fine sand in some enterprises, water accumulation in gravel storage, imperfect disposal measures for unqualified raw materials, incomplete original record information, and inability to trace the treatment process.
(IV) The authorization and record of production quality management
mix ratio adjustment are missing, for example, the authorization of mix ratio adjustment lacks the signature of the tester and operator, the scope of authorized adjustment (such as admixture) is too large and there is no maximum test verification; There are loopholes in the management of test blocks, such as the disconnection between the retention of test blocks and records, the production of impermeable concrete without retention of test blocks, the non-standard curing, the placement of test blocks in the curing room without gaps, the irregular marking, and the fact that some enterprises only use marking pens to mark information on concrete test blocks, but do not engrave marks as required, resulting in the risk of confusion.
(5) The design basis of mix proportion design
is not solid, for example, the design parameters of mix proportion have no scientific basis, are not reasonably set according to the characteristics of raw materials and construction requirements, some mix proportion design documents are incomplete, the apparent density is not measured, and the impermeability test results do not reach the specified pressure; The verification and adjustment are not in place. For example, the mix proportion verification does not include the chloride ion index, which can not meet the durability requirements of concrete, the mix proportion adjustment does not correspond to the test results of sand moisture content, the total water consumption is inconsistent with the actual production consumption, and the admixture and water consumption are inconsistent with the verification ratio.
(VI) Dust environmental protection management
and dust control are not in place, for example, the powder silo is not closed, the material receiving device at the lower part of the conveyor belt is imperfect or defective, and the weighing layer of the mixing plant has serious dust accumulation; the site environment is dirty, for example, there are problems of water, mud and dust accumulation in the site, and there is concrete accumulation under the main machine of the mixer and under the discharge port; Insufficient greening and cleanliness, such as no greening in some factories, poor sanitation in front of doors, and the overall environment does not meet the requirements of green production.
(VII) Chloride ion in group 1.1 of material sampling test
is unqualified, and the corresponding concrete enterprise is Changshu Yuneng Mechanical and Electrical Installation Engineering Co., Ltd. 2.21
groups of mud content are applicable to ≤ C25 concrete specified in the standard, involving 19 concrete enterprises. They are Suzhou Liangxing Concrete Co., Ltd., Suzhou Lion King Concrete Co., Ltd., Suzhou Liangxing Concrete Co., Ltd., Kunshan Qingyanggang Commodity Concrete Co., Ltd., Kunshan Zhonghuan Concrete Co., Ltd., Suzhou yuanhua Commodity Concrete Co., Ltd., Suzhou Huayi Concrete Co., Ltd., Suzhou Yixing Concrete Co., Ltd., Suzhou Xiangcheng East China Material Co., Ltd. Jiangsu Xin Concrete Building Materials Co., Ltd., Jiangsu Shuang Concrete Building Materials Co., Ltd., Changshu Yuneng Mechanical and Electrical Installation Engineering Co., Ltd., Suzhou Hongshun Building Materials Industrial Co., Ltd., Suzhou Tianhe Concrete Co., Ltd., Suzhou Jiuhe Concrete Co., Ltd., Jiangsu Shuangshan Commodity Concrete Co., Ltd., Suzhou Aide Concrete Products Co., Ltd., Suzhou Daxin Concrete Co., Ltd., Suzhou Hongsheng Commercial Concrete Co., Ltd.; the content of 3 groups of mud blocks is not applicable to the preparation of ordinary concrete, and the corresponding concrete enterprises are Suzhou Liangxing Concrete Co., Ltd., Jiangsu Shuangjian Concrete Building Materials Co., Ltd., and Changshu Yuneng Mechanical and Electrical Installation Engineering Co., Ltd. The content of group
3.4 stone powder and the content of mud block are applicable to the requirements of ≤ C25 concrete sand specified in the standard, involving 4 concrete enterprises, namely Liangxing Concrete Co., Ltd., Suzhou Huayi Concrete Co., Ltd., Taicang Jianguo Concrete Co., Ltd., and Suzhou Tianhe Concrete Co., Ltd.; The content of stone powder in Group 1 is not applicable to the preparation of ordinary concrete, and the corresponding concrete enterprise is Suzhou Huaxin Kanghong Concrete Co., Ltd. The silt content of
Group 4.3 is applicable to the requirements of ≤ C25 concrete sand specified in the standard, involving three concrete enterprises, namely, Suzhou Amity Concrete Products Co., Ltd., Jiangsu Defeng Concrete Co., Ltd., and Suzhou yuanhua Commodity Concrete Co., Ltd.; The mud content of Group 1 is not applicable to the preparation of ordinary concrete, and the corresponding concrete enterprise is Suzhou Daxin Concrete Co., Ltd.
(8) a total of 51 items were sampled for supervision
and sampling of physical concrete strength, and one item was sampled for each item supplied by the inspected concrete enterprise (within 10 days after the age of the test block under the same conditions should reach (600 ℃ d and ≥ 14 d)). Among them, industrial parks, high-tech zones, Wujiang District, Gusu District and Zhangjiagang are all qualified, while Taicang City, Wuzhong District, Xiangcheng District, Changshu City and Kunshan City each have one unqualified project.
3. Verification
(1) Enterprises
with better verification results 1.2.3
. Green production management is outstanding, dust suppression measures are appropriate, and production equipment is clean and tidy.
(II) Enterprises
found to be poor in verification 1.2.3.4.5.6
.
IV. Requirements
for the next step 1. All ready-mixed concrete enterprises should check the list of problems found in the inspection, carry out the reform immediately, and implement the closed-loop rectification. The housing and construction departments of county-level cities (districts) should focus on "common problems" to carry out special supervision, strictly supervise and guide enterprises to ensure that the rectification is in place within a time limit, trace the source of unqualified projects, increase the frequency of supervision and sampling of construction and concrete enterprises, and form a closed rectification report, which will be submitted to the municipal quality and safety supervision station before December 31.
2. All ready-mixed concrete enterprises must strictly implement the re-inspection of key indicators of raw materials, and establish a special rejection or return account for sand and stone with excessive mud content or mud blocks, so as to ensure the authenticity of data and traceability of the process.The housing and construction departments of county-level cities (districts) should strengthen supervision, investigate and punish enterprises using unqualified materials or false data according to law through random sampling and comparison, and check the traceability accounts, so as to urge enterprises to implement their main responsibilities.
3. The housing and construction departments of county-level cities (districts) should take the initiative to dock with the newly added ready-mixed concrete enterprises within their jurisdiction, improve the production quality control ability through policy publicity and technical guidance, help enterprises quickly grasp the operation process of "Suzhou ready-mixed concrete management system", and ensure that the quality of concrete is stable and controlled. For enterprises in the process of stopping production, the "management system" will automatically disable business permissions. Before the resumption of production, it is necessary to apply for the restoration of the right to use the system after on-site verification and confirmation by the local housing construction department.
4. Record yellow cards for the last 10 ready-mixed concrete production enterprises in the dynamic verification results, and record red cards for the enterprises in the dynamic verification results for two consecutive times. At the same time, according to the requirements of the Notice on Defining the Work Related to the Supervision and Sampling of Concrete Strength of Housing Construction and Municipal Infrastructure Projects in the City, credit punishment shall be imposed on the unqualified projects of concrete strength supervision and sampling (see Annex 2 and Annex 3).
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