Road engineering quality assurance system and quality assurance measures?

What is the road engineering quality assurance system? What are the quality assurance measures? Please read the article by the editor of Zhongda Consulting.

Road engineering quality assurance system and quality assurance measures

1. Quality assurance system and management organization

1.1. Quality assurance system

(1) Establish an ISO9002 quality system as the center, combining professional inspections with mass inspections, with all-round and full-process management of all employees as the content, with tracking monitoring, follow-up inspection, testing, strengthening the control of processes, key processes and irregularities. A quality assurance system with qualification control as the main means to achieve the company's quality policy and quality objectives. See "Quality Assurance System Block Diagram".

(2) Quality is the life of an enterprise, and the continuous and effective operation of the quality assurance system indicates that the enterprise has strong vitality. In order to ensure the effective operation of the system, we start with education and continuously enhance the quality awareness of all employees. Enable all employees to participate in quality activities and quality management, consciously accept inspection and supervision, and consciously maintain corporate reputation.

(3) Develop clear quality policies and quality objectives. Our company's quality policy is: relying on technology, standardized management, quality assurance, and customer satisfaction. The quality goals are: for railway construction projects, the first-time acceptance rate of unit projects is 100, the excellent and good rate is above 85, and the excellent and good rate at the completion of housing construction is above 50; for national key construction projects, the excellent and good rate is above 90, and we strive to create high-quality projects at the ministerial level and national level; For highway, water conservancy, municipal, airport, industrial and civil construction projects, the one-time acceptance rate of unit projects is 100, and the excellent and good rate meets the industry standards and industry requirements.

(4) Our company’s quality goals for this project are:

(1) Pass the one-time acceptance, reach the quality project of Guangdong Province, and strive for the Luban Award.

(2) The first-time acceptance rate of sub-projects is 100%, the excellent and good rate of sub-projects is more than 95, and the important sub-projects are excellent;

(3) The excellent and good rate of sub-projects More than 90%;

(4) Put an end to all quality liability accidents.

(5) Excellence planning:

1) Establish an excellence leadership group headed by the project manager, vigorously promote the famous brand strategy, formulate excellence measures and rigorous construction plans and implementation The detailed rules are broken down layer by layer and implemented to the individual team members.

2) Cover this project with the ISO9002 quality system to ensure that the system operates effectively in this project. In the operation of the quality system, all managements are standardized, standardized and programmed, quality management is promoted with scientific management, and product quality is guaranteed with work quality.

3) Formulate excellence acceptance standards, accept sub-projects and sub-projects, and establish strict process supervision and sub-project inspection and testing systems. Although sub-projects meet the "Quality Inspection" standards, However, if the standards for excellence are not met, acceptance will not be allowed; although the sub-processes meet the standards of "Bidding Inspection" but do not meet the standards for excellence, they are not allowed to enter the next process. Strict process control is used to achieve excellence in sub-projects, and strict classification is required. The company strives to achieve excellence in branch projects and unit projects.

4) Establish a quality excellence responsibility system and a strict reward and punishment system. In quality excellence activities, competition will be used to get jobs and the fittest will survive.

5) In the operation of the quality system, establish a quality ring and strictly control all links.

a. Control construction preparations to plan and arrange the site carefully and scientifically to ensure the smooth implementation of the project; b. Control the procurement of materials, components, and equipment to prevent substandard products from entering the site.

b. Control the process flow, compare the standards step by step, and compare the design everywhere, fundamentally laying the foundation for excellence and avoiding the occurrence of substandard products;

c. Control the important things During the construction process, in accordance with the design and specification requirements, refer to the construction organization design, quality plan, operation instructions, construction methods, operating process standards and acceptance standards, supervise random inspections and inspections at any time, and place important key processes and the entire construction process under strict supervision. , this is the core of quality assurance;

d. Carry out inspection and test control, including detection, monitoring, measurement, material and finished product testing and other means, as well as incoming inspection, process inspection, sub-item inspection , finished product and semi-finished product inspection, hidden inspection, final inspection and other items, the construction process can be tracked and monitored at any time. This is an important means of the entire project quality assurance system and the key to the success or failure of excellence. It is necessary to formulate inspection work procedures and operating systems to ensure the system of normal operation.

e. Carry out "unqualified" control, including purchased materials, purchased parts, semi-finished products, processes, procedures, etc. Generally, emergency releases are not made, and items that are not qualified will not be released.

f. Do a good job in document and data control, including documents and data related to the quality system, including program documents, quality records, correspondence, design drawings, technical specifications, acceptance standards, budget estimates, and bidding documents. , various on-site records of contracts and agreements, inspection and test data, telex, telephone records, etc. shall be controlled, and a registration system for sending, receiving, transmitting, modifying, invalidating, and archiving shall be formulated to prevent the use of invalid versions and cause accidents.

6) Regularly conduct internal audits of the system and apply for external audits in a timely manner.

(6) Key points of the quality assurance system

1) First establish a high-quality and efficient project team, which is the primary guarantee in the assurance system.

2) The quality of each work in the construction preparation stage is an important part of the system and an important part of the quality loop.

Construction preparation includes scientific site layout, accurate construction measurement, investigation of project environment including investigation of material sources, soil sources, geology, adjacent construction sites, surrounding buildings, transportation channels and other elements, and the preparation of design documents. Review and check, collect relevant specifications, standards, government regulations, owner's requirements and other documents, prepare implementation team, establish experimental monitoring institution, three connections and one leveling, pipeline modification, resource investment, including equipment capacity, labor quality, Technical strength, capital investment, etc. form an important part of the quality assurance system in the construction preparation stage.

3) Construction process control is an important part of the quality system and quality cycle. Including process, process control, inspection, testing, testing, monitoring means control, setting-out accuracy control, operating standard control and failure control, etc., determine the final quality of the product and mark the final result of each work.

4) The completion stage work is also an important part of the quality cycle. Including the quality of the project's closing supporting facilities, final inspection, unit project quality evaluation, original data collection and completion document preparation quality, technical summary and scientific research achievement level, etc.

5) Administrative reward and punishment means include quality responsibility system, competition evaluation system, quality one-vote veto system and other administrative control means, which are one of the means in the quality assurance system.

6) Total quality management means are an important part of the quality assurance system. Through the PDCA cycle and QC activities, the process quality is continuously summarized and improved, and the process and process quality development trends are predicted through mathematical statistics. It is proposed to Work quality ensures product quality, and weak links are pointed out in a timely manner so that they can be corrected in the next cycle, and QC research results are used to improve work and product quality, thus further improving the quality assurance system.

1.2. Quality management organization

Establish a project quality leadership group headed by the project manager and branch organizations led by the group, so that the quality management of the project is integrated into the network of organizational management and mass participation. The organizational form of the quality leadership group is shown in the figure below.

2. Quality management measures

1) After the project wins the bid, the project manager will preside over and lead the department heads and engineering and technical personnel of the management department to conduct a comprehensive and in-depth re-investigation of the site. Understand the on-site geological conditions, surrounding environment, traffic conditions, underground pipelines, drainage systems, adjacent construction sites, and finalize the site layout and construction plan.

2) Become more familiar with bidding, contract terms, design drawings, and strictly implement the relevant technical specifications, acceptance standards and related regulations of the country, Guangzhou City and the owner. On this basis, the implementation construction organization design and construction plan will be prepared and submitted to the owner and supervising engineer on time.

3) According to the approved implementation team, prepare the quality plan of this project, quality assurance measures for each part, professional technical operating procedures, technical requirements and process rules. We also organized technical briefings and issued work instructions.

4) In the operation of this project, formulate the scope of responsibilities of each management position and the management standards of each department; formulate tests, inspections, monitoring, routine inspections, random inspections, hidden inspections, process inspections, and sub-items Procedures for branch inspection and internal acceptance; establish document control procedures and unqualified control procedures for raw materials, semi-finished products, finished products and processes, and establish a regular internal audit system.

5) Establish and improve full-time quality inspection and mass "mutual inspection", "three inspections" systems and quality evaluation systems, sign quality responsibility letters at all levels, conduct strict assessments, and honor rewards and punishments.

6) Establish a comprehensive quality management system, carry out mass QC group activities, combine it with professional and technical research, establish projects, produce results, and transform results.

7) Establish a work plan for the quality leadership group, and regard the implementation of the excellence planning goals as the main work content and ultimate goal of the group. It is necessary to regularly analyze the activities, assign tasks for the next stage, and ensure that there are arrangements and inspections .

3. Various quality assurance measures

3.1. Concrete quality assurance measures

(1) Raw material assurance measures

Cement is given priority Portland or ordinary Portland cement of No. 425 and above produced by Dachang's rotary kiln.

The main technical performance indicators comply with the requirements of "Portland Cement, Ordinary Portland Cement" (GB175-92). When the cement is transported to the construction site, a cement factory quality certificate must be submitted and sampling tests must be conducted. Choose natural sand or hard rock machine-made sand with qualified grade, hard texture, and clean particles. Medium-coarse sand with a particle size of 0.16 to 5.0 mm should be used, and its mud content should not be greater than 3. The mud content should not be greater than 1, the solidity content loss rate should be less than 8, and the content of mica, light substances, sulfides and sulfates, and organic matter should all meet the specification requirements. Coarse aggregate gravel or pebbles are controlled according to the "Acceptance Standards", and the maximum particle size is no more than 40mm, the needle-like particle content is no more than 15, the mud content is no more than 1, the mud content is no more than 0.5, and the solidity weight loss The rate should not be greater than 8. The gravel and pebbles should be tested for alkali activity. The test should be performed according to specifications. The water used for concrete uses municipal tap water. The use of admixtures and admixtures complies with national standards (GB8076-87) and (GB1596-91) (GBJ146-90).

(2) Mix ratio selection and mixing quality assurance measures

Commercial concrete is used as the main structural concrete of this project. Our company’s central laboratory will contact the commercial concrete supplier,* **We also researched and designed the mix ratio of high-performance concrete that meets the needs of this subway project. Regarding the raw materials, mixing methods, and mixing processes used in the mixing station, our unit sent technical personnel to the station to verify, supervise, and check the cement varieties. Label, aggregate specifications, gradation and other physical and chemical indicators, measurement accuracy of various mixing materials, admixtures and admixtures, mixing time, supply speed, etc., and contact the construction site at any time.

(3) Concrete construction organizational measures

1) Establish a concrete pouring construction management group headed by the deputy project manager, which is mainly responsible for the implementation of relevant organizational management work of concrete pouring construction to ensure Concrete is continuously supplied and constructed according to specifications and prescribed construction techniques to ensure the quality of concrete construction.

2) Before concrete pouring, the chief engineer of the project should organize relevant personnel to conduct technical briefings and clarify the concrete pouring process, characteristics, construction precautions, etc. The project manager should organize the supply and transportation of construction machinery and commercial concrete, The labor force is arranged, and the technical and quality inspection departments make quality control plans.

3) Send a dedicated person to the mixing station to be responsible for the monitoring of mixing quality and supply and transportation liaison.

4) During pouring, the project department organizes relevant technical, quality inspection, testing and other personnel to form an on-site duty team to inspect and supervise the implementation of the concrete pouring quality control plan.

5) Implement the concrete pouring quality responsibility system, assign responsible persons in each pouring area and keep construction records. Quality inspection personnel will follow and supervise at any time to prevent the phenomenon of honeycomb pockmarks and exposed tendons.

(4) Concrete construction site control measures

1) Commercial concrete is delivered to the construction site using a mixer truck. Practical and reliable transportation routes must be developed to ensure that it reaches the construction site within the specified time. On site, stir for 2 minutes before discharging the material, check the ingredient list, and then take it out of the tank. After the concrete is taken out of the tank, pay attention to measuring the subsidence and making test blocks.

2) Concrete is poured using a concrete delivery pump.

3) Adopt segmented, block-based, and layered pouring. The thickness of each layer is generally 30cm~40cm. The length of the segments should not exceed the initial pouring time of the first-poured layer and the later-poured layer. The setting time is measured as a degree, and the side walls of the integrated pipe trench are poured symmetrically in sections. Unilateral construction is prohibited from causing deformation of the model and formwork.

4) Tamping should be followed by pouring and tamping. When vibrating, the concrete should be tamped to the surface floating slurry at each vibration point and no longer settles. The moving distance of the vibrating rod should not be greater than 1.5 of the radius of action. times. The lower concrete should be inserted 5cm-8cm each time, and the formwork, steel bars and embedded parts should not be collided during vibration.

5) The comprehensive pipe trench structure pouring is assembled using large steel molds and fasteners. The model must be specially designed and calculated to ensure the strength, stiffness and stability of the model. The support support must be strong and reliable, and there must be no displacement, deformation, or slurry leakage during pouring.

After the model is erected, it should be inspected and construction records should be kept. The error should not be greater than the value specified in the specification. The template should be painted with release agent.

6) After the initial setting of the concrete, manual slurry lifting, compaction and troweling must be carried out before final setting.

7) Cover the new concrete immediately after it is poured. Do not pour open-air concrete structures on days when they are not directly exposed to the sun, wind or rain.

When the concrete enters final setting, sprinkle water on the covering straw bag for curing, and keep the surface moist at all times. The curing period is 14 days.

3.2. Structural anti-leakage measures

Structural leakage is caused by poor material selection, lax construction control or improper mix ratio, and lack of strict control of the process. In order to prevent leakage in concrete structures, the following measures are planned:

(1) Establish a waterproof construction leadership organization and take measures to strictly control

Establish a waterproof construction leadership organization with the project manager as the team leader The leading group, led by the chief engineer of the project, is responsible for the construction of this project. It consists of full-time supervisor engineers and quality inspection engineers. It organizes technical training for construction personnel, conducts technical briefings on waterproof construction, and achieves the following:

Comprehensive understanding of waterproofing The raw materials used in the project shall be strictly controlled, giving priority to products with good performance, good effects and easy construction. Quality inspection shall be carried out before entering the site to avoid the use of inferior raw materials;

During construction, the engineer in charge and the quality inspection engineer must Carefully guide and inspect the construction behavior of the waterproof construction team on site, and strictly control it in accordance with the construction process details. Anyone who fails the inspection will be ordered to correct it immediately;

After each waterproof construction is completed, the quality inspection engineer will first Carry out inspection, and then submit it to the supervision engineer for inspection and acceptance after passing the inspection. Only after passing the inspection can you enter the next process of construction and complete the handover of the process.

(2) Quality control measures for waterproof concrete construction

1) Designing the mix ratio and construction process of waterproof concrete and implementing standardized operations are the primary measures to prevent structural leakage .

According to the principle of "prevention first, combination of prevention and drainage, adapting measures to local conditions, and comprehensive management", the focus is on prevention, and waterproof concrete is a specific form of improving the self-waterproofing of the structure. The mix ratio of waterproof concrete must be designed well, and high-efficiency admixtures should be used first. Improve the impermeability grade and implement construction control;

2) All raw materials used in waterproof concrete must comply with technical standards and design requirements, and must be submitted to the supervision engineer for approval. Admixtures and admixtures should be incorporated according to the design to improve the impermeability. In order to reduce the amount of cement, reduce the heat of hydration and the temperature difference between inside and outside, reduce slump loss, and avoid the occurrence of cracks, add no more than 10% of the cement amount of fly ash and no more than 5% of the silica fume, and all the fine powder must pass through 0.15mm. Sieve hole screening;

3) The mix ratio of waterproof concrete is determined through experiments and the anti-permeability level is increased by more than 0.2Mpa compared with the design. The cement dosage, sand rate, lime-sand ratio, water-cement ratio and slump are all stipulated in the "Technical Specifications" and are strictly measured during construction;

4) Strict construction control. All aspects of "raw materials - mixing - transportation - mold placement - pouring, vibrating - maintenance" must be fully paid attention to and strictly controlled. The raw materials must be inspected and tested, and must be signed by the supervisor; they must be fully stirred, and the mixing must be delayed appropriately according to the performance of the admixture; try to transport them at night to avoid delaying the transport time; the model must have sufficient stiffness, and no mold leaks must be allowed during pouring If segregation occurs, cement slurry with the same water-cement ratio can be added for secondary mixing; it must be poured in blocks and in layers, vibrated layer by layer, without under-vibration or over-vibration, and the interval between upper and lower concrete pouring should not exceed 45 minutes to ensure that the upper and lower layers of concrete are combined before initial setting to prevent cold seams from forming; after the concrete enters final setting, start sprinkling water for curing and keep the surface moist at all times for 14 days;

5) Waterproof concrete It is necessary to pour continuously and leave as few construction joints as possible. The comprehensive pipe trench shall be carried out in sections and layers as designed;

For weak parts of the concrete structure such as construction joints, structural joints, reserved holes for embedded pipe fittings, etc., the construction technical measures described in the relevant chapters shall be followed Handle it carefully.

3.3. Preventive measures for groundwater corrosion of structural concrete and steel bars

According to geological data and groundwater test results, if groundwater and rock soil are corrosive to concrete structures and steel bars, they can be Take the following measures:

Improve the compactness of concrete structures. For concrete structures that are in direct contact with groundwater and rock and soil, quality control should be strengthened during construction to ensure compactness. When spraying concrete, it must be uniform and dense, and the parts with steel bars must be sprayed from different angles;

Use special cement, such as fly ash cement, etc., to increase the erosion resistance of the concrete;

Derust the surface of the steel bars to ensure tight bonding with the concrete;

When pouring waterproof concrete, control the molding temperature and strengthen maintenance to ensure that the width of concrete cracks is not greater than 0.2mm.

The above is collected and compiled by Zhongda Consulting

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