A high-temperature day operation safety precautions
1. Reasonable arrangement of work and rest time, to avoid the high temperature period, while the morning and evening of the cooler time to seize the construction.
2. Summer heat open-air work should be strictly in accordance with the requirements to wear a good helmet.
3. Employees should learn the summer safety construction knowledge, master the relevant prevention and protection skills.
4. High-temperature workplaces in enclosed (semi-enclosed) spaces should take appropriate measures to improve ventilation and cooling to avoid heat stroke.
5. High-temperature weather should be a good pressure vessel to prevent high temperature, sun protection treatment.
6. Summer heat should pay attention to personal hygiene, do not eat unclean food; anti-mosquito bites, prevent seasonal diseases.
7. Summer construction weather is hot, more slippers, bare shoulders on the job, these cases should be strictly prohibited and strengthen the correct use of labor protective equipment and wear the inspection.
8. Summer construction should do a good job of fire prevention measures, oxygen and acetylene cylinders in the use of the process should be strictly abide by the safety regulations, and do a good job of anti-exposure.
Second, steel construction
1. Steel is strictly prohibited from randomly stacked, should be unified arrangements for transportation and stacking.
2. Reinforcing steel processing plant and construction site semi-finished products stacking place, should be good waterproof rust prevention measures.
3. Stacking should be at the bottom of the pad on top of the wood, to prevent the accumulation of water on the rebar caused by corrosion.
4. In rainy weather, cover the rebar with geomembrane and check whether the geomembrane leaks.
5. It is strictly prohibited to pile up on the excavated plain soil, which will easily make the square wood fall into the soil and make the rebar and the soil come into direct contact with each other, which will cause the rebar to rust and corrode.
6. outdoor construction in summer, handling rebar is strictly prohibited when the workers bare hands in direct contact with the rebar, so as not to cause burns.
7. When tying rebar, take good protective measures.
Third, the construction template
1. Summer construction template centralized stacking, should be placed in the site of the fire fighting equipment, to avoid the dry temperature caused by fire.
2. When the materials are stacked together, personnel should be arranged to patrol the site without open fire.
3. Construction templates, beams, wall templates must be left to clean the mouth or outlet, template demoulding agent should be covered with plastic sheeting in case of rain to prevent the isolation layer from being washed away by rain.
4. Steel pipe racking materials such as support on the backfill, should be well padded sleepers, pads, after the rain should be checked in a timely manner templates, bracket firmness, stability, and template cross-section dimensions and so on whether there are changes.
5. Rainy day use of wooden templates removed and flattened to avoid deformation and timely cleanup, brush release agent such as heavy rain should be re-brush again.
6. Pour concrete as soon as possible after the template is assembled to prevent deformation of the template in the sun and rain. If the template can not be assembled in time after pouring concrete, and rain, before pouring concrete, re-inspection, reinforcement of the template and support.
7. Templates and components: hardening of the stacking site, inserted firmly. The template supported on rainy days, before pouring concrete after the rain, the template and support should be carefully checked to prevent the template support from loosening.
8. When the large template falls to the ground, the ground should be solid, and support firmly.
9. The template and square wood used in the main structure should be lifted and transported to the designated yard in a timely manner after dismantling to prevent the template and square wood from being exposed to the sun and rain.
Fourth, concrete construction
1. proportion adjustment
Adjustment of proportion should be given full consideration to the loss of slump, in order to reduce the loss of slump of the concrete, to avoid the concentration of heat of hydration. Raw materials can be adjusted to use lower heat of hydration of cement, but also by adjusting the admixture of composite additives to delay the setting time of concrete to meet the construction requirements.
2. Concrete mixing and transportation
Mixing concrete in the hot season should take effective measures to control the concrete mixing temperature. Through the use of low-temperature water mixing, the use of cool water rinsing of aggregates, as well as measures to control the temperature of cement into the machine, so as to reduce the concrete mixing temperature.
(1) In summer, cool water is poured on the concrete transportation body in order to avoid the heat of the steel tank body transferring into the concrete resulting in the rise of concrete temperature. Every time before the concrete construction, the construction of each concrete truck should be required to use water to wet the cooling, to avoid evaporation of water in the concrete due to high humidity and reduce the quality of the construction of concrete.
(2) During the transportation of concrete, the road should be kept flat and smooth, and the concrete should be kept homogeneous in the transportation process, so that it will not be delaminated and segregated when it is transported to the pouring place, and it will have the required slump and air content and other working properties.
(3) pumping construction of concrete, the pumping pipe requires the use of felt wrapped, and regularly sprinkled on the surface of the pumping pipe to reduce the pumping pipe due to sunlight, concrete friction temperature rises, to avoid the loss of concrete slump and the phenomenon of blocking the occurrence of the pipe.
(4) when the concrete filling, pay attention to the water and mortar wetting pump pipe. The transportation capacity of the concrete transportation equipment should be adapted to the needs of the concrete setting speed and pouring speed to ensure that the pouring process is carried out continuously.
3. Pouring of concrete
(1) Strengthen the temperature observation during construction, which can avoid temperature cracks.
(2) take appropriate temperature control measures: reduce the pouring temperature, in the concrete construction should pay attention to the aggregate sunscreen, add ice chips or ice water mixing concrete, transport containers covered to prevent sun exposure; reduce the temperature rise of heat of hydration, choose reasonable raw materials, the use of good mixing ratios to reduce the cement dosage; to prevent surface cracks, you can take to increase the surface temperature of the concrete, such as in the The exposed surface of the concrete structure is covered with heat preservation, set up heat preservation shed and covered with plastic film.
(3) Pouring large volume concrete, can be buried in the structure of the cooling water pipe (serpentine pipe), through the circulation of water for cooling.
4. Concrete maintenance
Concrete poured in the summer, such as improper maintenance, will cause a reduction in the strength of concrete or plastic shrinkage cracks on the surface, etc..
(1) Immediately after the completion of finishing operations or after the initial setting of the concrete, curing, using sprinkling curing method, continuous curing. In the first 7 days after the concrete is poured, it should be ensured that the concrete is in a sufficiently moist state.
(2) Upon completion of the specified curing, it is desirable to provide a moist cover for the surface when the membrane is removed.
(3) The water used for concrete curing must be tap water or tested water source, not sewage or acidic water. The number of sprinkling times should be measured by the wet state of the concrete surface.
(4) such as artificial sprinkling, spraying maintenance, the concrete surface can be used geotextile, sacks, cotton felt and other water-absorbent materials covered (wrapped) tightly, without revealing edges and corners, sprinkler spraying intervals are short. Covering inside and outside from beginning to end to maintain moisture, prevent wet and dry cycle. Generally speaking, the temperature of the curing water should not be lower than 15 ℃, and the difference between the temperature of the curing water and the surface temperature of the concrete should not be higher than 15 ℃, in order to prevent cracks on the surface of the concrete.
(5) such as the use of concrete surface wrapped plastic film moisturizing maintenance, plastic film should have a certain crack resistance, tensile strength, and flexibility. After the concrete is demolded, the surface of the concrete should be sprinkled with water to moisten, and immediately wrapped tightly, the plastic film should be tightly attached to the surface of the concrete, without leakage, airtight.
During the curing period, water droplets should appear on the surface of concrete since the beginning. In order to keep the surface of the concrete wet state, can be regularly sprayed to the plastic film sprinkler, to frequently check the integrity of the film. If you find a plastic film open rupture and other phenomena, to repair the integrity in a timely manner.
(6) According to different weather and temperature conditions and different structural characteristics, high-performance concrete curing period should be generally controlled within 14-28 days. In this curing period, the use of heat insulation curing measures to ensure that the concrete curing humidity to meet the requirements, so that the hydration of the concrete is carried out smoothly.