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Concrete mixing station summer concrete construction technical measures

2015/7/10 14:01:54 Click:
At present, the construction has entered the summer construction period, and the air temperature continues to rise. In order to prevent the concrete from entering the mold temperature to exceed the high temperature, the performance of the concrete mixture is guaranteed to meet the requirements of the specification. We must control concrete temperature, mixing properties and other measures. How to deal with summer concrete construction technology measures.

One general provisions

One point one When the temperature is higher than day night Thirty At low temperature, effective measures should be taken in the construction of concrete works according to the requirements of summer concrete construction.

One point two Concrete mixing station and laboratory should do well in temperature detection and recording.

One point three In summer concrete construction, the temperature of concrete is not higher. Thirty-five The mold temperature should not be higher than the temperature. Thirty C.

Two Measures for raw material storage and cooling

Two point one As the temperature increases in summer, we should use sunscreen and sunscreen to treat cementitious materials, fine aggregate, coarse aggregate Chu Cuncang, pile up, etc., or spray water on the fine aggregate and coarse aggregate to cool down, so as to reduce the temperature of raw materials entering the mixer.

Two point two Use cooling device to cool mixing water, add shade and heat insulation to water pipes and water tanks, and add crushed ice into mixing water as part of mixing water. Crushed ice should be used for mixing water quality control and measurement.

Two point three Cement must be stored for a certain time to cool down after entering the field. After testing, the temperature of cement entering the mixer should not be greater than that of the mixer. Forty C.

Three Mix proportion design of concrete

Three point one The design of concrete mix should take into account the high environmental temperature in summer and the loss of slump. Water reducing agents with high water reducing rate, good Slump Resistance and certain enhancement effect should be selected.

Three point two Concrete should be selected with low hydration heat cement and mixed with a certain proportion of fly ash to replace part of cement to reduce the amount of cement, slow down the hydration heat reaction of cement and reduce the temperature of concrete.

Three point three When the retarding water reducing agent is incorporated, the amount of water reducer can be adjusted appropriately according to the temperature, but it can not exceed the original mixing ratio. + 0.1% The slump of concrete should not exceed the original ratio. + 10mm The volume of concrete should not exceed the difference between the original mixture ratio and the gas content. + 0.5%

Four Mixing process control of concrete

Four point one Concrete mixing plant hopper, water storage, belt conveyor, mixing plant and other mixing production lines should take shade measures as far as possible.

Four point two In summer, the temperature is high. According to the performance requirements of concrete mixture, concrete mixing time can be shortened as far as possible, and suitable mixing time is selected after trial.

Four point three In the process of concrete mixing, the slump of concrete should be often measured. The construction mix ratio of the concrete is adjusted to meet the slump requirement of the construction.

Four point four In summer concrete construction, it is advisable to arrange and mix concrete at night or at low temperature to ensure that the concrete mold temperature meets the design requirements. When the design is not required, the mold temperature should not exceed the temperature. Thirty C.

Five Concrete transportation

Five point one Concrete is suitable for transporting concrete by concrete transport mixer. Concrete containers should be equipped with sunscreen facilities to minimize transportation time.

Five point two Concrete should be slowly mixed with concrete during transportation. No water should be stirred during transportation.

Six Concreting

Six point one Before the summer concrete is poured, it should be well prepared and fully equipped with concrete equipment to ensure continuous casting of concrete.

Six point two Concrete placement should be carried out at a lower temperature in a day.

Six point three The site should be shaded to reduce the temperature of the formwork and steel bar, so that water can be cooled by spraying water on the formwork, reinforcement and foundation. But there should be no adhesive water when pouring.

Six point four After pouring concrete, surface should be speeded up or plastered. Spray can spray a small amount of water to prevent surface cracks, but not directly sprinkle water on the concrete surface.

Seven Concrete curing

Seven point one After pouring concrete, the surface should be covered with clean plastic film immediately. After the initial solidification, remove the plastic film and cover with a wetted geotextile, and cover with a plastic film. Ensure wet condition 7d

Seven point two It can also spray cooling on the concrete surface, moist air and other maintenance measures. .

Seven point three When conditions permit, pre cooling technology measures are taken at the bottom of the template.

Seven point four During the wet maintenance of concrete, sun shading and wind blocking measures should be adopted, and the influence of temperature and dry hot air on the concrete should be controlled.

Seven point five The sprinkling system and sprayer should be used for watering after concrete removal. Wet curing shall be continuous and dry wet cycle shall not be formed.

Seven point six Large volume concrete should be maintained in advance, and the curing time should not be less. 28d