Hot summer conditions may cause cracks in the poured concrete, which will seriously affect the quality of the entire construction project。How can we reduce the temperature during concrete pouring in summer？Chongqing Shiqiao Dinggu Construction Machinery Co., Ltd. put forward the following suggestions: 1.优质Concrete mixingThe following measures should be adopted to reduce the aggregate temperature in the material field: ① The aggregate of the finished material field, the stacking height should not be too low, and there should be sufficient reserve;② Take material through ridge;③ Build pergola, spray fog (except sand), etc。2.Pre-cooling coarse aggregate can be pre-cooled by air cooling, soaking water, spraying cold water and other measures。If water is used for cooling, there should be dehydration measures to keep the water content of the aggregate stable。3.When mixing concrete, cooling measures such as low temperature water and adding ice can be used。When adding ice, ice or ice chips can be used, and the mixing time can be extended appropriately。4.Reduce the temperature rise of concrete (1) shorten the transportation time of concrete, promptly smooth the concrete after warehousing, speed up the concrete warehousing covering speed, shorten the exposure time of concrete;② Concrete transport vehicles should have heat insulation and sunshade measures;3.优质Concrete mixingproducerIt is advisable to use spray fog and other methods to reduce the air temperature around the warehouse surface.(4) Concrete pouring should be arranged as far as possible in the morning and evening, night and cloudy days;⑤ Before the concrete levelling after warehousing is completed to the next layer of concrete, it is appropriate to use thermal insulation to cover its top joint。Summer concrete in the construction process should pay attention to every step of preventive measures, only in this way can improve the quality of the overall construction project。

Concrete mixing is an operation method of mixing cement, lime, water and other materials evenly。Concrete mixing is divided into two types: manual mixing and mechanical mixing of water。优质Concrete mixingproducerConcrete mixing plant is widely used in China's industry, agriculture, transportation, national defense, water conservancy, municipal and other construction projects, the demand is increasing。Cement concrete mixing plant is widely used in China's industry, agriculture, transportation, national defense, water conservancy, municipal and other construction projects, the demand is increasing。Although the domestic concrete mixing equipment continues to innovate and progress on the basis of learning from foreign products, the technical level is gradually improved, but as far as the whole mixing station is concerned, the research on the batching process is still insufficient, especially for the new concrete mixing station, often rely on the experience accumulated by supporting manufacturers for many years.西安优质Concrete mixingIt basically meets the quality requirements of the national standard for concrete mixing station, and there is no special experimental research on its conveying technology and feeding technology。

The purpose of concrete mixing is to make each component of concrete mixed into a mixture of each material particle dispersed with each other and evenly distributed。Whether the mixed concrete has a uniform texture,优质Concrete mixingproducerA certain number of samples can be randomly selected from the concrete for analysis to assess, if the mix ratio of each sample is basically the same, it can be considered that the concrete has been mixed evenly。In order to make the components of the concrete mixed evenly, it is necessary to disperse the particles of each component to the other components during the mixing process, therefore, it is necessary to try to make the components have movement, and make their movement track intersect, the more the number of intersecting, the easier the concrete is to mix evenly。According to the different methods of forcing each component to produce an intersecting motion trajectory, there are basically two mixing mechanisms based on the design of ordinary concrete mixers: 1.Self-falling diffusion mechanism: it is to lift the material to a certain height, using the effect of gravity, free fall, due to the height, time, speed, falling point and rolling distance of each material particle。Thus, the material particles interpenetrate, permeate and diffuse, and then achieve the purpose of uniform dispersion, because the dispersion process of the material is mainly the use of gravity, it is also called gravity diffusion mechanism, and the self-falling concrete mixer is designed according to this mechanism。2.Forced diffusion mechanism: It is the use of moving blades to force the material particles to move from all directions (circumferential, radial and vertical), so that the direction and speed of the movement of the material particles are different, resulting in shear slip between each other so that each material is interspersed and diffused, so that the material is evenly mixed。Concrete mixingproducerBecause the diffusion process of the material is mainly based on the shear slip effect between the material particles, it is also called shear diffusion mechanism。

一.Selection of raw materials and their temperature control 1.Cement cement should give priority to Portland cement, ordinary Portland cement early strong cement, in order to improve the early strength of concrete, reduce the frequency of freezing damage。2.Sand and stone should be preferred to use inventory sand, because the relative water content of inventory sand is low, the production of frozen blocks is less, and the relative performance is stable;Such as the new sand in winter, the water content of the incoming sand should be strictly required (controlled below 4%) to reduce the freezing probability and the adjustment frequency of the mix ratio during production to ensure the quality of concrete。The relative moisture content of stones is low, the probability of producing frozen blocks is small, and it should be avoided by rain and snow。In order to ensure the normal use of aggregate, it is recommended to cover the sand and stone on the site with sand mesh or felt, so that it is protected from rain and snow, and can play a certain role in insulation。The accumulation height of yellow sand and gravel should be appropriately increased, and if the material is sufficient, 5-8m is appropriate to reduce the freezing layer and protect the internal temperature。3.Mixing water Mixing water is drinking water, winter construction should use hot water mixing, water temperature control at about 60 ° C, but not higher than 80 ° C。4.Antifreeze Antifreeze contains antifreeze components, antifreeze components can reduce the freezing point of water, so that concrete is still hydrating under negative temperature conditions。When testing and using admixtures, it is necessary to strictly control the properties of antifreeze and the amount of admixtures。5.Due to the different fineness of admixtures such as fly ash and mineral powder, the micro-aggregate effect occurs in concrete, which improves the compactness of concrete.优质Concrete mixingThat is, the strength, frost resistance and durability of concrete are improved, but fly ash and mineral powder can extend the hydration time of cement。Therefore, the amount of admixture should be appropriately reduced during construction in winter。二.In order to ensure the normal operation of the equipment and the normal production of concrete, the feeding port of the aggregate bin, the admixture tank and the mixer should be closed, and the hot spot (furnace and electric heating) should be set, and the electric heating should be added in the operation room when there is air conditioning。Conditions should be used boiler heating, heating pipe should be through the bone bin feeding port, admixture shed, pool, mixer shed and operation room, not only save time, labor, but also better ensure the concrete out of the machine temperature and performance。三.Concrete transport vehicles under the jurisdiction of the company's mixing transport vehicles, in the winter before construction outsourcing insulation, to the mixing truck insulation, to ensure that the temperature of the concrete during transport does not lose。After the mixer is loaded, it is strictly prohibited to add water to the car at will to prevent the quality of delivery from being affected by changes in the water-cement ratio of concrete during transportation。After the mixer shaper, the water in the tank should be cleaned in time to prevent ice from causing quality hazards。四.The control test personnel of the production process test the moisture content and temperature of the sand and stone every day, and the number of tests should be increased in rain and snow weather。Depending on the climatic conditions, the concrete only needs to be mixed with hot water, and the aggregate does not need to be heated。The quality inspection personnel should check the temperature of the mixing water before each opening, which should not be higher than 80 ° C to prevent the phenomenon of false coagulation in the concrete;It shall not be lower than 40 ° C to ensure that the temperature of concrete entering the mold shall not be lower than 5 ° C。Strictly control the amount of antifreeze, and extend the mixing time of concrete to ensure the uniformity of concrete。五.Quality control of concrete after application 1.Quality inspection personnel shall be arranged at the construction site, responsible for vehicle deployment and concrete quality control。Compress the unloading time of concrete as soon as possible to ensure the temperature of concrete entering the mold。2.Concrete mixingproducerBefore pouring concrete, the construction site quality inspector should check whether there are factors affecting the quality of concrete such as frozen blocks or snow on the surface of the formwork。3.After concrete pouring is completed, the construction unit should be notified in time to cover the concrete with plastic film and blanket and other thermal insulation maintenance work to ensure that the concrete is not damaged by freezing before the initial setting.The concrete shall not be watered and cured during winter construction, and the strength of the concrete shall reach 1.Before 2MPa, do not step on it, support the mold and load。4.After the concrete pouring is completed, the quality inspection personnel should remind the tank truck driver to clean the concrete mixing truck with water。5.After mold removal, the difference between the surface temperature of concrete and the ambient temperature is greater than 20℃, and the insulation covering maintenance measures should be taken。The quality of concrete not only needs the strict control of the mixing station, but also needs the support and close cooperation of the construction unit, and the above measures can ensure that high-quality concrete can be produced in winter。