In the usual study and work, everyone will inevitably come into contact with the thesis, which is a kind of reasoning article that conducts research in various academic fields and describes academic research results. You had no idea when you wrote your paper? The following is my carefully arranged paper on the influence, causes and prevention strategies of cracks in cement concrete structures. Welcome everyone to refer to it, I hope it will help you.

Abstract: Cement concrete, also known as cement concrete, is composed of water, cement and a variety of mixed materials, and is widely used in engineering construction. Because the construction of cement concrete structure will be affected by many factors such as temperature, humidity and technical conditions, cracks are easy to appear in the process of use. Combined with engineering practice, this paper briefly analyzes the causes of cracks in cement concrete structure construction, and puts forward relevant preventive measures.

Keywords: engineering construction; Cement concrete structure; Cracks; Structural diseases;

Cracks in cement concrete structures are common structural diseases in cement concrete construction. If the treatment is not timely, it will cause serious structural damage to cement concrete, which will not only increase the construction cost of cement concrete structure, but also shorten the service life of cement concrete structure. Due to the tight construction period of some cement concrete structures and the untimely treatment of cracks in cement concrete structures, the cement concrete structures can not meet the predetermined requirements in the use process. In the actual construction process, based on the analysis of the causes of cracks in cement concrete structure, the technical scheme of construction prevention should be formulated in time to ensure the continuous and effective construction of cement concrete structure.

1, common types of cracks in engineering construction

1. 1 cracks caused by assembly and distribution problems of cement concrete

On-site construction personnel's empiricism, failure to grasp and adjust the cement concrete ratio in time, blind use of laboratory ratio, failure to adjust the cement concrete structure ratio in time according to the construction site conditions, or unqualified raw materials are all likely to cause cracks in the cement concrete structure. For example, the mix ratio of cement concrete structure, if raw materials, water, additives and other factors are not properly controlled, the structural strength can not meet the design requirements, and cracks will occur [1].

1.2 cracks caused by environmental reasons

Cracks caused by environmental reasons of cement concrete structure mainly refer to cracks caused by changes in environmental factors such as temperature and humidity during the construction of cement concrete structure. When environmental factors such as temperature and humidity change greatly during construction, the physical properties of cement concrete structure will change, and then cracks will appear.

1.3 cracks caused by foundation.

Cracks in the foundation of cement concrete structure mainly refer to the cracks caused by the failure to compact and tamp the backfill soil during the construction of cement concrete structure; If the foundation soil is too soft and the cement concrete structure is not compacted before construction, cracks will also appear in the cement concrete structure. If the cement concrete structure is soaked by seepage in the foundation for a long time, uneven cracks will also appear [2].

1.4 cracks caused by improper maintenance in the later period.

In the process of cement concrete construction, cement concrete should be cured in time. If the curing is not timely, there will be dry shrinkage cracks on the surface of cement concrete and "peeling" on the surface of cement concrete; Or because the temperature is not enough to reach the final setting condition of cement concrete, the whole cement concrete appears "broken plate" phenomenon.

2. Influence of cracks on cement concrete structure

It is easy to bury potential safety hazards, because cracks in cement concrete structures will affect the original bearing capacity of cement concrete buildings, thus shortening the normal service time of cement concrete structures. In the process of building construction, the existence of cracks may cause a lot of repairs, waste materials, delay the construction period, and ultimately cause huge economic and reputation losses. Cracks in cement concrete structure will have a great impact on the appearance quality of buildings, affecting the quality acceptance of projects and the settlement of subsequent payments.

3. The causes of cracks in cement concrete structure in engineering construction.

In the construction process of cement concrete structure, cracks will appear in cement concrete structure due to the influence of many factors such as temperature, humidity, raw materials and construction technology.

3. 1 Influence of raw materials

Raw materials in cement concrete play an important role in the quality of cement concrete structure. Once unqualified raw materials are used in the construction process, cement concrete is prone to cracks: too much mud content in coarse and fine aggregates leads to insufficient bonding force with cement; Excessive needle-like proportion of coarse aggregate and uneven proportion of coarse and fine aggregate will lead to insufficient compactness of cement concrete; The optimum water consumption and initial and final setting time of cement will have an impact on the overall strength of cement concrete structure and the later maintenance of cement concrete structure.

3.2 the influence of construction technology

In the process of cement concrete structure construction, scientific construction technology should be adopted to strengthen the management of key elements such as project management system and construction organization design time node. During the construction of cement concrete ground, the original ground should be leveled, compacted and tamped by layers, otherwise cracks and "broken slabs" will occur on the cement concrete pavement due to uneven stress. In the construction of cement concrete pavement, the cement concrete pavement should be vibrated and compacted, and the service life of cement concrete pavement should not be affected by void. In the process of cement concrete construction and maintenance, it is necessary to observe and monitor the changes of moisture and temperature in time, grasp the initial setting and final setting time of cement concrete in time, and implement watering and covering thermal insulation facilities. The formwork can only be removed after the final setting of the cement concrete structure, so as to avoid the cracks caused by the cement concrete structure not reaching the strength and affecting the normal use of the cement concrete structure.

3.3 the influence of physical properties

Because cement concrete is a brittle material, the temperature and humidity in the environment have great influence on it. When the temperature and humidity values change greatly, the stress of cement concrete structure will also change accordingly, resulting in cracks in cement concrete structure.

4. Preventive measures for cracks in cement concrete structure in engineering construction

Cracks in cement concrete structure will bury hidden dangers for the whole structure of buildings, which may affect people's lives and property safety. Through the analysis of the causes of cracks in cement concrete structures, it is necessary to take active preventive measures before, during and after.

4. 1 Matters needing attention in the design process

Scientifically formulate the mixture ratio of cement concrete. When formulating the mix proportion scheme of cement concrete structure, the water-cement ratio should be controlled reasonably, and the addition of various additives should conform to the actual situation of the construction site. When the mixture ratio of cement concrete in the laboratory meets the construction requirements, it is necessary to adjust the mixture ratio in time on site, and it is not always possible to rely on the mixture ratio results of the laboratory. According to the height, width and length of cement concrete structure, the distribution of steel bars is adjusted in time to make the stress distribution of cement concrete structure uniform. Strengthen the quality monitoring of cement concrete raw materials and put an end to the use of unqualified raw materials. According to the actual situation, timely and reasonably adjust the mixture ratio of cement concrete.

4.2 Preventive measures in the construction process

The construction process of cement concrete structure is a key step affecting the engineering quality, and the scientific construction process is an important factor to determine whether the cement concrete structure produces cracks. Pay attention to the smoothness of the original base of cement concrete structure before construction; Carry out the construction in strict accordance with the design and technology to ensure the reasonable construction mix ratio of cement concrete structure and meet the quality requirements of design strength and material workability of cement concrete structure; In the process of cement concrete transportation, corresponding protection measures such as water retention and heat preservation should be taken for cement concrete; In the process of cement concrete pouring, the discharging speed of cement concrete should be controlled in time to ensure the compaction and uniformity of vibration in the process of cement concrete structure pouring. Attention should be paid to the important role of secondary plastering in cement concrete construction engineering, which can reduce the occurrence of cracks in cement concrete structure. When plastering for the second time, the initial setting time and final setting time of cement concrete structure should be grasped in time. If the plastering time is too late, the cement concrete structure has gradually solidified, and even plastering cannot change the physical appearance of the cement concrete structure. If the plastering time is too early, cracks will occur in the cement concrete structure after secondary plastering, which will not affect the physical appearance of the cement concrete structure. Therefore, the construction personnel need to control the plastering time, and plastering should be carried out during the initial setting and final setting of cement concrete structure, so as to reduce the occurrence of cracks and improve the quality of cement concrete structure [3].

4.3 Preventive measures in the process of maintenance

The maintenance of cement concrete structure should be carried out in strict accordance with the national standards for the maintenance of cement concrete structure, so as to minimize the cracks of cement concrete structure. It is necessary to strengthen the monitoring of temperature and humidity, and control the temperature, humidity and technical conditions of cement concrete maintenance in strict accordance with the design requirements of cement concrete structures; Measures should be taken to reasonably control the range of temperature and humidity values. In construction, plastic film and straw mat can be used to cover the surface of cement concrete structure to ensure the temperature of cement concrete structure, and timely manual sprinkling can be used to ensure the humidity required by cement concrete. In addition, in the process of engineering construction, in order to ensure that the curing period of cement concrete structure meets the requirements of specifications, the curing period of cement concrete structure is usually 7 ~ 15d, and the specific curing time in the process of engineering construction should be determined according to the actual wind, temperature, humidity and other factors on the construction site [4].

5. Concluding remarks

At present, the construction of cement concrete structure has been widely used in various projects, and the quality of cement concrete structure directly affects the engineering quality. This paper briefly analyzes the causes of cracks in cement concrete structure construction, and puts forward measures to prevent cracks in cement concrete structure. However, there are many factors involved in cracks in cement concrete structures, which are hard to avoid in actual engineering construction. In the construction process of cement concrete structure engineering, the prevention and control of cement concrete structure cracks should be carried out from all aspects of construction, thus effectively ensuring the quality and efficiency of engineering construction and the service life of buildings.

Step 6 refer to

[1] Feng Shuhe. Causes and prevention of cracks in cement concrete structure in engineering construction [J]. Jiangxi Building Materials, 20 14(3):74.

[2] tachileik. Cause analysis and preventive measures of cracks in cement concrete structure based on engineering construction [J]. China Folk Houses (next issue), 20 14(6):333-334.

[3] Xiaochun Zhao. Causes and prevention of cracks in cement concrete structures in engineering construction [J]. Guide to Getting Rich through Science and Technology, 20 14(29):262.

[4] Shen Yaping. Causes and prevention of cracks in concrete structures in building construction [J]. Sichuan Cement, 20 15(6):225.

;