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Looking back 2016, silk in many ways have a new breakthrough. Outlook 2017, the new year, there are new tasks; new year, there are new expectations. In the new year, the slightest edge convinced that we will usher in a new dawn, usher in a new development opportunities!
Today to share: construction tip
For winter construction, the impact of temperature is the primary concern in the construction process to ensure that the appropriate temperature of construction materials, construction plays an important role in the construction! Here to introduce the concrete structure of the project, in the winter construction should pay attention to some of the relevant matters! Little companions come onlookers!
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1. years of temperature data, outdoor daily average temperature for 5 days stable below 5 ℃, the concrete structure should take winter construction measures; and should take timely and sudden drop in the temperature of the anti-freeze measures.
2. Concrete pouring in winter, the compressive strength of concrete before freezing shall not be less than the following:
⑴ Portland cement or ordinary portland cement preparation of concrete, for the design of concrete strength standard value of 30%;
⑵ slag Portland cement preparation of concrete, for the design of concrete strength of the standard value of 40%, but not greater than the C10 of concrete, not less than 5.0N / m ㎡.
3. Preparation of concrete in the winter construction, should be preferred to use Portland cement or ordinary Portland cement. Cement strength grade should not be less than 32.5, the minimum amount of cement should not be less than 300kg / m3, water-cement ratio should not be greater than 0.6 mixed with antifreeze concrete, is strictly prohibited the use of high-alumina cement.
4. Winter pouring of concrete, should use chlorine-free antifreeze, the requirements of high frost resistance of concrete, should use air-entraining agent or air-entraining agent.
5. When the concrete is used, the chlorine salt content shall not be greater than 3% of the weight of the cement.
6. Aggregate used in concrete must be clean, shall not contain ice, snow and other frozen objects and easy to crack the minerals. In the mixed with potassium, sodium ion antifreeze in the concrete, shall not be mixed with active aggregate.
7. Mixing antifreeze containing concrete should meet the following requirements:
(1) the preparation of antifreeze solution and antifreeze dosage should be consistent with the relevant provisions of the existing national standards;
⑵ strict control of concrete water-cement ratio, from the aggregate into the moisture and antifreeze solution in the water should be deducted in the mixed water;
⑶ stir before the application of hot water or steam flushing mixer, stirring time should be taken at room temperature stirring time of 1.5 times;
⑷ concrete mixer temperature should not be lower than 10 ℃, into the mold temperature should not be less than 5 ℃.
8. Concrete in the pouring before the removal of the ice and dirt on the template, transport and pouring concrete containers should have insulation measures.
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9. Templates and insulation layer should be cooled to 5 ℃ after the concrete can be removed; when the concrete and the outside temperature difference is greater than 20 ℃, the demolition of the concrete surface should be taken to slow down the temporary cooling measures.
10. The curing of concrete with antifreeze should meet the following requirements:
⑴ in the negative temperature conditions of conservation, is strictly prohibited water and exposed surface must be covered;
(2) the initial curing temperature of concrete shall not be lower than the specified temperature of antifreeze, fail to reach the specified temperature should immediately take insulation measures;
⑶ mixed with antifreeze concrete, when the temperature dropped to the antifreeze below the specified temperature, its strength should not be less than 3.5N / m ㎡;
⑷ When the demolition of concrete surface temperature and ambient temperature difference is greater than 15 ℃, the concrete should be covered with insulation materials conservation.
If necessary in the winter construction of small partners, pay close attention to collection myself! Hope to help you!
The slightest message
After spending a happy and peaceful Spring Festival holiday, we will return to work again. We must abandon our work with more full of enthusiasm, more solid style, more effective measures, and devotion to work "No fifteen is the year" thinking, as soon as possible into the working state, consciously put the thinking and action to this year's work objectives and tasks up.
Finally, the silk edge look forward to working with you to glory! Wish you in the new year: family happiness, happy go hand in hand!
Concrete structure, construction precautions
