外文翻译

Thesis Keywords：Highway Engineering Quality control of construction perfusion

Abstract In this paper, on many years of working experience, first of all start from the highway construction process, quality control start on, focusing on the highway project preparation phase, three aspects of the construction process, the completion of stage 11 were analyzed, the final focus from the concrete quality assurance aspects are discussed, pointing out three aspects of the specific guarantees of the quality of concrete measures: concrete mix design and management; concrete construction organization measures; concrete quality control measures for the reader is referred to.

A highway engineering concrete quality defects and their causes

The common problem of concrete quality is important factor to affect the quality of highway projects has become a prominent issue of restricting the quality of structural engineering; its main crack overrun, the protective layer thickness deviation exceeding the joint surface is not handled properly, Tendon grouting false ; which have a direct impact on the durability and security of the structural quality of the project, reducing its reliability and useful life of.

Concrete quality defects specific cellular, pockmarked face, exposed ribs, holes and other performance type, each common problem, especially causes. But overall, its a common problem reasons can be divided into three performance types: concrete mix than irrational design and management; improper concrete construction organization; concrete quality control is not strict.

Cellular problem is the concrete structure local crisp, mortar, gravel, stones formed between the phenomenon of the honeycomb-like holes. Its causes are: concrete mix than improper or material measurement are not allowed to cause less mortar, gravel; concrete mixing time is not enough, not mixing well; cutting concrete in stratified vibrators false or omitted to vibration, or vibration time is not enough; template gap is not blocking Yan, grout loss; foundation, columns, foot of the Ministry is not a little intermittent continue filling the upper concrete. Ma surface is the surface of the concrete local shortage of pulp and many small pits, pitting, forming a rough surface, but the exposure of reinforcing bars. Main causes: the template surface roughness, or adhesion of grout residue and other debris is not cleaned up, form removal when the concrete surface is glued bad; template patchwork of lax local leakage of plasma; template release agent brushing uneven, or local leakage brush or failure of the concrete surface caused by the template bond pockmarked face; concrete vibrators are not real, the bubbles are not discharged, parked in the surface of the template the formation of pitting.

Exposed tendon problem is the internal reinforcement of concrete, vice tendons or the stirrups partial nudity in the phenomenon of the surface of

structural members. Generated causes are: pouring the concrete pad displacement of the reinforcement layer or pad too little or of missing, resulting in reinforced close to the template exposed; cross-section of structural members, steel too close, gravel stuck in the reinforced on cement mortar can not be filled with reinforced around, causing the exposed tendons; concrete mix properly, resulting in segregation, lack of a paste or slurry leakage rely on template site; concrete protective layer is too thin protective layer at concrete vibrators false; wooden template is not watering moist. absorbent bond or release too early, the lack of edge in the form stripping off angle, resulting in leakage tendons.

Two, the common problem of concrete quality control measures

2.1 concrete mix design and management

The concrete mix ratio is an important factor to control the quality of concrete, with selected characteristics based on where the project site, construction techniques, technical requirements and construction environment to determine the performance of concrete construction technology, concrete construction technology performance by different materials and use of the proportion of experimentally determined.

1) mix design to meet the relevant requirements. Before construction, according to the performance test of the two kinds of concrete construction technology formulated the theory of a variety of concrete mix for the select. Concrete with the addition to meet the technical specifications and design requirements, but also to the durability of concrete requirements.

2) with the ratio of management. ①The tenders concrete technical performance higher, the admixture and the admixture of the more varieties, in order to ensure that the concrete quality, and the entire concrete mixing the whole process of supervision and management. ②According to the selection of concrete with the state of the material and mechanical condition of the equipment to determine the construction mix ratio. Construction with the quality objectives in conjunction with the theoretical ratio is. Construction tie than single-ingredient mixing concrete mixing station, mixing station are required to take appropriate management measures to ensure the proper use of mixture ratio. ③Press tie strictly than the organization of concrete supply, each pouring of concrete must be tested before being shipped into the perfusion face.

2.2 Concrete construction organization measures

Concrete Construction Quality five factors are: the construction environment, construction techniques, steel, formwork and the pouring of concrete construction, the pouring of concrete construction in the five factors influenced by natural conditions. Therefore, take the following measures to ensure the quality of concrete construction.

1) the establishment of the Deputy Project Manager, the pouring of

concrete-based construction management group, is mainly responsible for the implementation of the pouring of concrete construction organization and

management, to ensure continuous concrete supply and organize the construction of the construction process, thus ensuring the quality of the pouring of concrete.

2) before the pouring of concrete, concrete construction technology, construction and technical performance characteristics and construction Note the technical disclosure by the project chief engineer organization workers. Deputy Project Manager is responsible for organizing the corresponding construction machinery, concrete transport and operating labor arrangement. The project quality control, technical, and waterproof operating group of

full-time responsible for the quality of the corresponding parts of the perfusion and quality inspection and supervision.

3) the project manager, quality, technical, mechanical and electrical, materials and the Ministry of the composition field duty team, specializing in the implementation of the concrete supply and construction technology is the construction of the fabric craft organizations and to urge the construction of key parts, such as waterproof structural details such as concrete quality.

4) full-time concrete testing personnel stationed in the concrete mixing station to oversee the mixing station press with the implementation of quality control of the situation and assist in organizing transport.

5) the pouring of concrete construction to implement a quality contract responsibility system, the project manager responsibility for quality contracts signed with workers and mixing station, concrete quality and construction and concrete economic benefits of the supply station directly linked, and to develop appropriate incentives, mass quality research and rationalization of the proposed activities to mobilize the relevant personnel.

2.3 Concrete quality control measures

The quality of the concrete formation process is divided into: raw materials and co-ordination than the design → concrete mixing and transportation → pouring of concrete, three stages.

1) raw material selection and mix design is an important stage of the quality of the concrete itself and quality through the adoption of strict scientific testing means and management measures, so that the concrete quality than can easily be controlled; mixing transport of concrete, as well as injection, perfusion stage affect the quality of concrete are many factors to ensure that the concrete in construction quality, take the following measures to ensure the quality of the concrete transport and perfusion.

2) concrete mixing and transport. Concrete mixing station quality management excellence goal range, included in this project to assist the mixing station to develop appropriate control measures based on the quality of concrete technical performance requirements. ②mixing station before each mixing, the mixing measurement should check the technical state of the control device to ensure that according to the construction with the measurement of mixing, construction should be adjusted according to the status of the material in a timely manner to the use of the various materials, accurate adjustment, an

owner supervision.

3) the pouring of concrete. (1) formulated the pouring of concrete implementation of the program, the development of equipment, personnel, small equipment and transport organization plans, project deputy manager of the organization and implementation plan. ②each time before pouring of concrete, the Deputy Project Manager to develop the implementation of concrete supply and transport plan, complete with a variety of transportation equipment, to coordinate a variety of transportation equipment, travel time and route, and spare the corresponding power internal combustion generator. Concrete (3) concrete mixing plant shipped the first single-compliance by the pilot to check verification and ingredients with the perfusion than the request before being transported to the face. Not meet quality control requirements, or slump loss exceed the standard, and more than allow the transit time of the concrete for disposal. ④supply in accordance with the infusion process and concrete symmetrical perfusion. Infusion process to organize the supply of the good Concrete transport, shortening the perfusion time, to avoid the construction of cold joints. ⑤With the infusion of the concrete, tamping should be timely concrete tamping, concrete vibrators do not take bubble prevail, but shall not exceed the vibration caused by the concrete turned to sand and coarse aggregate sinking.

Third, the conclusion

The road project is a popular project, its quality is directly related to the pros and cons of China's infrastructure construction and the long-term stability of the national economy. Through this discourse, is willing to provide a boost for our technological advances in related fields. Based on the restriction of work experience, the individual problems of the text and not fully discussed, and will continue to continue to strengthen the learning of this knowledge in order to achieve greater results.

References

[1] Zhou Jianqi, Yu Wubin. Cement stabilized aggregate base course construction technology and quality control method [J]. Communication Science & Technology, 2003,04.

[2] Wang Zhongchen. Construction phase of highway projects the quality of various factors and countermeasures [J]. Science and Technology Information (academic research), 2007,10.