Application of construction concrete thermal insulation measures in building construction?

What are the applications of construction concrete thermal insulation measures in building construction? The following Zhongda Consulting Bidding Teacher will answer your questions for your reference.

because the construction of water conservancy projects requires safe flood season, the length of the construction period not only has an important impact on the benefits of water conservancy projects, but also meets the needs of safe flood season, so it is inevitable to carry out winter construction frequently. Hanzhuang Canal and Zhong Canal are located in the southwest of Shandong Province and the north of Jiangsu Province, which are the provincial boundary rivers of Sulu Province. The average temperature in this area for many years is 14℃, the highest temperature over the years is 39.6℃, and the lowest temperature is -19.2℃. Generally, the winter construction period is from mid-December to mid-February of the following year. According to the Code for Construction of Hydraulic Concrete (DL/T5144—21), when the daily average temperature is kept below 5℃ for five consecutive days or the minimum temperature is kept below -3℃ for five consecutive days, the construction shall be carried out in the low temperature season. The concrete construction measures of water conservancy projects in winter in this area will be discussed according to the hydrometeorological conditions in this area. 1 Prepare for winter construction, organize relevant personnel to learn concrete winter construction regulations, make careful arrangements for construction procedures, anti-freezing, temperature measurement, quality and safety, and make technical disclosure for winter construction at the same time to ensure that each working procedure is organized according to specifications and technical measures. Train the technicians, builders, materials engineers, testers, team leaders, temperature measuring personnel, welders, admixture mixing and aerial work personnel of important types of work, and master relevant construction schemes, construction methods and quality standards. During the winter construction period, assign special personnel to watch the weather forecast information, make records, and timely convey relevant personnel. Secondly, prepare winter construction materials, and equip them with enough anti-freezing and cold-proof materials to make preparations before winter construction. 2 Heat preservation measures for mixing system 2.1 Aggregate A. Control the temperature of various raw materials of concrete, and keep the aggregate warm a few days before pouring to ensure that there is no ice, snow and frozen lumps in the aggregate during pouring. B reserve enough sand and gravel, pile them as high as possible, and cover them with daylighting plastic film to prevent ice and snow from freezing, so as to keep warm. C. According to the needs of the construction progress, the sand and gravel shall be insulated with a semi-closed insulation shed, which shall be built with steel pipes, covered with lighting plastic sheets and insulation grass felt, and equipped with a heater. 2.2 mixing water mixing water gives priority to underground well water, and it is used with pumping. According to the weather conditions, a hot water heater is set near the mixing station to prevent the cold weather from being used as a backup and ensure the supply of hot water for concrete mixing. 2.3 concrete mixing a. Before concrete mixing, rinse the mixer with hot water and remove ice, ice water and accumulated water. B. increase the concrete mixing time. The mixing time of concrete in winter operation is 1.5 times of normal temperature. C. mixing concrete with hot water. D. Adding antifreeze to make concrete harden at negative temperature. The dosage of antifreeze admixture or the concentration of aqueous solution for preparing concrete shall be determined according to the instructions of antifreeze. E within the slump range determined by the laboratory, reduce the water cement ratio as much as possible, thus increasing the hydration heat and shortening the time to reach the age strength. F. Reasonable arrangement of construction organization. Arrange the concrete pouring in a favorable period, avoid the cold current in the construction time, and try to pour and close the warehouse in the high temperature period during the day. 2.4 concrete transportation a. shorten the transportation time of concrete as much as possible, give priority to mechanical transportation of concrete, and increase concrete transportation equipment. B try to reduce the number of concrete transshipment, reduce heat loss, and ensure that the concrete warehousing temperature is not lower than 5℃. C. The charging equipment shall be covered and the side wall shall be insulated to reduce the heat loss during transportation. 2.5 Thermal insulation and maintenance of concrete According to the scale of the project and the field situation of the project, the thermal insulation and maintenance measures of concrete with disposable fixed greenhouses are adopted. That is to say, a shelf is built around each warehouse surface with scaffolding poles, and the top cover is tied and fixed with steel pipes. Because of the large volume and area of the thermal insulation greenhouse, in order to prevent overturning, strong steel pipe columns are added around the greenhouse. Around the scaffold and the top surface, a plastic film for lighting is laid, and the outside of the plastic film is covered with a straw mat for heat preservation. All the pouring surfaces are covered under a greenhouse, and the inside of the greenhouse is heated by a coal-fired stove, and an aluminum basin is placed in the coal-fired stove to boil water to generate steam, so as to keep the humidity of concrete and avoid cracks caused by concrete drying. After concrete pouring, the exposed surface shall be insulated in time. Especially in the joints and corners of new and old concrete, the insulation layer thickness is twice that of other surfaces, and the lap length of insulation layer is not less than 3cm. Thin-walled structures such as wing walls and bottom plates that have been poured, as well as edges and corners and protruding parts, will be protected. Before dismantling the formwork, the concrete strength shall be detected by concrete rebound instrument, and then whether the formwork can be dismantled shall be determined, and the following provisions shall be observed: a. When dismantling the non-load-bearing formwork, the concrete strength must be greater than the critical strength or maturity value allowed to be frozen, and the critical strength or maturity value shall be controlled according to 85% of the design strength value. B. The removal of bearing formwork is determined by calculation, and shall be carried out after being approved by the supervision engineer. C. Formwork removal time and protection after formwork removal shall meet the requirements of temperature control and crack prevention, and the temperature difference between inside and outside shall not exceed 2℃ or the temperature drop of concrete surface shall not exceed 6℃ within 2 ~ 3 days. D. Avoid ripping at night or when the temperature drops suddenly. When the temperature is low, when it is expected that there will be a sudden drop in temperature after formwork removal, the formwork removal time will be postponed; If it is necessary to dismantle the formwork, protective measures shall be taken at the same time. Within 28 days of age, the concrete shall be coated with curing agent twice in time after the formwork is removed, and a layer of grass felt with a thickness of 1cm shall be covered on the plastic sheet. 3. Safe production and civilized construction in winter A. Maintain the construction road, clear the snow on the ground with a loader after snowfall and use fly ash for anti-skid treatment, and arrange a steel baffle on the outside of the concrete formwork to prevent concrete transport vehicles from rushing into the warehouse to ensure driving safety. Clear the snow and ice on the construction road in time, increase the turning radius at the road corner, and spread anti-skid materials on the pavement. B when there is ice and snow on scaffolding and scaffolding, it should be removed before construction. C. In case of bad weather such as rain and snow, the accumulated water and snow on the construction site should be removed in time, and it is strictly forbidden to organize construction work forcibly in rain, snow and windy weather. D. antifreeze and anti-skid. After frost and snow, the operation surface should be cleaned in time, and the temporary operating frame and limb protection facilities used must be checked by safety management personnel before they can be used again, so as to prevent falling accidents from heights caused by frost, snow and too slippery site. 4 Other problems that should be paid attention to in construction A. The key to winter construction is to do all kinds of heat preservation measures and control the hydration heat of concrete. Therefore, before construction, the erection of thermal greenhouses, the planning of transportation lines and the heat preservation situation should be carefully checked to reduce the heat loss and ensure the temperature in the greenhouse. B. Pay attention to control the temperature of various concrete raw materials, and keep the aggregate warm a few days before pouring, so as to ensure that there is no ice and snow and frozen lumps in the aggregate during pouring. During construction, we should pay attention to measuring the temperature of various materials every hour, and control the temperature at any time to ensure the temperature of concrete entering the mold. C. When mixing concrete in winter, the mixing time must be extended by 5% compared with normal temperature. Strictly control the sequence of feeding: aggregate → water → mixing → cement → mixing, and add an appropriate amount of antifreeze. D. Because there is an open flame in the greenhouse, it is covered with plastic film and grass felt, so it is necessary to raise the awareness of fire prevention and prepare sufficient fire-fighting equipment. Smoking is strictly prohibited in the shed, and safety measures should be taken before welding. E. All kinds of exposed pipelines at the site shall be wrapped with heat preservation materials or buried below the frozen soil layer to prevent water pipelines from freezing and cracking. 5 Conclusion Hanzhuang Canal and Zhongyun Canal belong to warm temperate and semi-humid areas, with continental climate, which has the characteristics of transition from north to south and distinct seasons. The thermal insulation measures for the winter construction of hydraulic structures in this project are very representative in the surrounding areas of Sulu, Henan and Anhui, providing a practical and effective reference scheme for the winter construction of hydraulic structures in this area, increasing the construction period by two months, effectively improving the construction speed, shortening the construction period, creating conditions for safe flood control, and the thermal insulation measures are simple, with little investment and great results.

for more information about the engineering/service/procurement bidding, and to improve the winning rate, you can click on the bottom of official website Customer Service for free consultation:/#/? source=bdzd