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How to ensure the quality of concrete construction in the face of high temperature weather? The following small series will introduce you to the measures and skills on how to ensure the quality of concrete construction under high temperature conditions
For example, when pouring a concrete wall, the size of each layer shall be reduced to shorten the pouring and vibrating interval of two layers
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If conditions permit, it is best to use water storage for curing( 5) During maintenance, it is necessary to prevent sudden change of temperature and avoid exposure, wind and rainstorm
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Therefore, it is advantageous to avoid sunlight and construct at night( 4) The concrete has high temperature and fast setting, so it is easy to produce poor connection, so the construction interval shall be shortened as much as possible, and the volume change of concrete during cooling is also large, and the mass concrete is more prone to cracks
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If it cannot be covered, spray water on the surface to prevent drying( 2) The concrete surface with flat surface and plastering can be cured by covering film or spraying plastic film curing solution( 3) In order to make the concrete surface harden without damage, when covering with linen, straw curtain, sugarcane, etc., it shall be fully watered and kept wet within 7-14 days
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“Three volt” days are the hottest time of the year
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A lot of practice has proved that this is an effective method
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Therefore, the concrete temperature at the time of pouring shall be lower than 35 ℃( 5) For some important structures, construction in high temperature season shall be avoided as far as possible, and construction in cool weather or at night shall be selected when necessary
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Therefore, the formwork, reinforcement, bedrock and old concrete at the place to be poured can be watered to cool and absorb enough water before pouring
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Therefore, the following problems should be paid attention to when curing concrete: (1) after pouring, the surface of concrete should be covered with film immediately
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The construction site shall be arranged as far as possible when the temperature is low in white weather and the slump of concrete disappears quickly in hot weather
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Therefore, it should be kept wet for a certain period of time
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Therefore, the pouring and tamping of concrete shall be rapid, and the construction operation shall be fine, strict, serious and meticulous( 3) For the concrete poured during the day, due to the temperature reduction at night and the heat generated by the concrete, the internal and external temperature difference of the concrete is easy to produce cracks
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Dry goods sharing: the head of the laboratory in the standardization area pays attention to us by two yards.
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The high temperature of concrete will accelerate the water evaporation of concrete, and the high temperature will promote the evaporation even more
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Pouring of concrete (1) when pouring concrete in hot summer, if the object in contact with the concrete is high temperature and dry, the cement in the concrete will hydrate very quickly, and the water in the concrete will not be absorbed and hardened completely
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Equipment for blocking sunlight and preventing ventilation shall be adopted at the pouring site to avoid temperature rise and drying( 2) During the pouring process, the pouring and vibrating time interval of new and old concrete shall be short
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The rapid evaporation of water on the surface of poured concrete will cause defects such as poor hardening and cracking of concrete, so as to reduce the quality of concrete
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It is best to keep warm with thermal materials at night when the temperature changes greatly( 6) For fly ash concrete, wet curing shall be carried out for at least 14 days, and for concrete of important structures, wet curing shall be carried out for at least 28 days
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When curing is stopped, it shall also be gradually dried to avoid drying shrinkage cracks
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If only closed covering without watering, the surface will often dry and crack due to rapid hydration heat in the first three days, especially in the first day( 4) When the concrete with earlier age is watered for curing, if the operation is interrupted, the concrete will be wet and dry, which is easy to cause cracking
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