The basement of a residential district is 1 layer, and the ground is 9 layers, the main body of the project is frame structure, and the concrete of C30 grade is used in the main structure. In the construction of the project, all the concrete materials are in the form of commercial pumped concrete, and a car pump is used in the process of the main construction to complete the concrete pouring construction. The overall concrete structure is not negligible in terms of workload in the construction of the whole structure, so the corresponding control measures are taken in the process of structural concrete pouring construction.

　　1 Construction preparations before concrete placement

　　First of all, we should carefully check the specific situation of concrete supplier’s material preparation to ensure sufficient supply of materials in construction. In order to better ensure the smooth implementation of the construction, the location around the bungee in the pouring construction should also be set up bright concrete mixing and transporting vehicles, in addition to ensure the drainage effect of the site.

　　The second is to conduct a comprehensive inspection of the state of work of the various equipment and facilities applied to the construction to ensure that they meet the requirements of the construction.

　　Once again is the concrete in the pouring construction before must do a good job of cleaning up, pouring the surface of the bin inspection qualified before the concrete pouring construction.

　　The last point is that in order to better ensure that the old and new concrete construction joints can have a good combination effect, before the first layer of concrete pouring construction, must lay and concrete grade exactly the same cement mortar, mortar thickness to be maintained at 2-3cm, the area of the mortar laid must be coordinated with the strength of the concrete pouring, in addition, in terms of thickness should also have a very good uniformity In addition, the thickness should also have a very good uniformity, so that it can also be very effective in avoiding the phenomenon of laying thickness when thick and thin.

　　2 Concrete ratio and quality control of raw materials

　　First of all, before the construction of concrete pouring must be a comprehensive check of the commercial concrete manufacturers and self-mixing concrete test inspection report, sand and gravel and mud content should be controlled at a relatively reasonable level gravel grade must be in a relatively good state sand and gravel mud content should be relatively low, preferably medium coarse sand, but also to ensure that the raw materials do not contain materials that affect the quality of concrete, while the cement Can not use expired or untested cement, in the construction of the cement itself to be a comprehensive check of stability, the choice of admixtures should choose the industry response to the products produced by manufacturers, but also to ensure that all the materials in the concrete are qualified products.

　　Secondly, before pouring construction, the manufacturer must have more raw material reserves, the construction needs to use granite gravel and coarse yellow sand, fly ash, etc. should fully meet the requirements of construction, while in the preparation of admixtures, must be fully based on the specific type of admixtures and production to prepare all types of admixtures required for construction.

　　Once again, because the concrete in the production and transportation and pouring and other construction processes may produce very obvious defects, in order to ensure the smooth progress of construction and reduce the number of construction joints, the final setting time of concrete must be in between 6-8 hours, while the final setting time of concrete must be maintained at more than 4 hours after delivery to the construction site.

　　Finally, the slump of concrete for the top slab must be between 120-140MM and the slump of concrete for the columns should be between 160-180MM. The temperature in the mold should be controlled between 200-300°C.

　　3 Control of concrete placing process

　　First of all, it is divided into blocks. Each building is in the form of splitting blocks per floor, and during the pouring process, one transfer pump should advance parallel from west to east and pour backwards. The second is splitting the layers. In the over?E of pouring construction should take the way of inclined stratification, adopt the way of gradual progress, and ensure the place at one time when pouring. Two large layers should be used in the construction, that is, the column part of the pouring construction should be completed first, and then the beam part of the pouring construction should be completed afterwards. The concrete pouring time for columns and beams should be kept at about 2 hours. The column should be pounded in layers, and the thickness of each layer should be controlled within 500mm.

　　4 Concrete pouring method control

　　4.1 Column:

The column bars and beam bars are crossed in the column formwork, and the gaps are small and scattered. Before construction, a solid sample should be placed to ensure sufficient space for placing and vibrating, and the concrete should be poured in layers and fully vibrated to ensure that the concrete is poured densely.

　　4.2 Beam slab:

when pouring, pay attention to the concrete pouring of overhanging members (ensure the protective layer of negative moment tendons); use flat vibrator to vibrate; strictly control the concrete elevation; pour the middle part of the beam first and then pour the outside, and the lag of wall column concrete should not exceed 2 hours; the concrete of the platform should not be piled too high; pay attention to the cleaning of debris in the mold and wetting of the formwork.

　　4.3 Staircase:

the staircase and the column should be separated by wire mesh; pouring should be consistent with the column pouring; concrete should be placed and pounded from bottom to top; concrete should be placed by tower crane; attention should be paid to pounding and leveling; pre-buried iron parts should be buried in the leveling.

　　5 Concrete pouring project control

　　5.1 Concrete pouring must be operated strictly according to the specifications to avoid leakage of vibration and over-vibration.

Detailed work instructions should be prepared before concrete pouring, and detailed technical instructions should be given. Vibrating personnel must have many years of practical experience in vibrating.

　　5.2 When concrete construction, each transfer pump is equipped with 4 sets of 5cm insertion vibrators, 2 sets are arranged at the unloading point and 2 sets are arranged at the bottom entrance of the slope to strengthen the quality of vibrating, while 2 times vibrating the concrete, that is, when pouring the upper layer of concrete, first insert the vibrator into the lower layer of concrete, and immediately pour the upper layer of concrete after vibrating the lower layer of concrete evenly once. Insert the vibrator into the lower concrete 50mm deep to vibrate.

　　5.3 When placing the column, the thickness of the concrete should be strictly controlled.

For the convenience of construction, column concrete can be placed in sections, but the thickness of each layer should not exceed 500mm, and be equipped with long wooden poles, flashlights and other tools for inspection. When pouring in layers, vibrating the upper layer of concrete should be carried out before the next layer of concrete first set, and the vibrating rod into the next layer of concrete about 5cm, vibrating time to depending on the surface of the concrete flooded mortar and does not sink shall prevail, the distance of movement of the vibrating rod does not exceed 50cm, vibrator distance from the formwork is not more than 18cm. larger pre-buried parts, to leave the air holes, construction to ensure that the buried parts under the mouth of the concrete dense The concrete under the buried parts should be dense.

　　5.4 The concrete of the floor should be poured from one end of the construction section to the other in order to retreat, and the thickness of the virtual concrete is slightly greater than the thickness of the slab. The concrete of the beam should be pounded by insert vibrator first, and then the floor concrete should be pounded by flat vibrator.

　　5.5 concrete surface elevation control.

Will be 70cm long Ф14 reinforcement according to @ 4m × 4m spacing spot welded on the column or floor reinforcement, with a level will be 50 elevation line lead on, and red paint as a marker, when pouring pulling the line to control the elevation and flatness of the plate.

　　5.6 Surface treatment of concrete.

After the concrete is poured for 2~3h, surface treatment is carried out. When surface treatment is carried out, the surface is initially scraped with a large wooden bar according to the elevation, and rubbed flat with a wooden trowel before the initial setting, and repeatedly wiped and pressed no less than 3 times to close the water collection cracks.

　　5.7 After the pouring is completed, the temperature and slump of concrete in the mold will be randomly checked to ensure that the temperature and slump of concrete in the mold are fully controlled and meet the requirements.

　　Conclusion

　　In the construction of concrete casting construction, must take effective measures to constantly enhance the quality control of concrete casting, which is a relatively systematic and complex work, if its quality does not meet the requirements of design and construction, it will have a very significant impact on the concrete structure, concrete casting construction, if there is a quality problem, it is necessary to re-construction processing, so Only by doing a good job of quality control of pouring construction can we better ensure the effect of construction.