How concrete heat storage is done. What is the difference with general heating

You're using aerated concrete.

The thermal conductivity of aerated concrete is generally kilocalorie m o hour o degree, only 1 4-1 5 of granular soil brick and lime sand brick, (the thermal conductivity of granular soil brick is kilocalorie m o hour o degree; The thermal conductivity of lime sand brick is kilocalorie m o h o degrees), which is about 1 6 of ordinary concrete. Practice has proved that the thermal insulation effect of a 20 cm thick aerated concrete wall is equivalent to the thermal insulation effect of a 49 cm thick clay brick wall, and the thermal insulation performance is also much better than that of a 24 cm brick wall.

In this way, the thickness of the wall is greatly thinned, and the effective usable area of the building is expanded accordingly, the thickness of the building material is saved, the construction efficiency is improved, the project cost is reduced, and the self-weight of the building is reduced.

There is no difference in heating, no problem. The refrigeration is not enough, and some cooling capacity can be compensated in the fresh air. Because the temperature of the floor slab is too low, condensation will occur.

The heat storage method is a maintenance method that uses insulation materials to cover to reduce the temperature loss of concrete, and uses concrete heat and cement hydration heat to increase the strength of concrete to reach the critical strength of freezing.

The hydration of cement depends on the presence of water and the maintenance of a certain temperature. This is done slowly at low temperatures, and if the temperature drops below 4, the water begins to expand. When the temperature of the concrete drops below the freezing point (the freezing point is lower than O due to the alkalinity of the liquid phase), it will not only cause damage to the cement particle structure due to volume expansion, but also due to the freezing of the chemical water, and the new composite will be greatly reduced, resulting in a decrease in strength, durability and impermeability.

After thawing, although it can continue to grow, the strength will be lost in the later stage, and the longer the freezing time, the greater the loss. Therefore, when the average temperature of the day is stable below 5, or when the minimum temperature is stable below -3, in order to ensure the quality of concrete, a series of low-temperature construction measures should be taken to make the concrete not suffer from freezing and accelerate solidification in the early stage.

When the temperature is O4, the setting time of concrete is 3 times that of 15; The temperature is -5 0～-0.At 30C, it starts to freeze, and the hydration reaction basically stops; At -10, the hydration of the cement stops completely and the strength of the concrete no longer increases.

To ensure that the concrete is not damaged by frost, the first is to artificially create positive temperature curing conditions;

The second is to accelerate the hardening of concrete, as soon as possible to reach the critical strength before freezing;

the third is to distort the ice crystals or reduce the volume expansion when freezing, and the concrete structure will not be damaged when frozen;

The fourth is to lower the freezing point of water, and the water will not freeze at negative temperature, and can still continue to hydrate.

The heat storage method is to store the hydration heat of the concrete itself and the heat obtained from the outside world through thermal insulation measures, so that it has a suitable positive temperature environment and continues to hydrate the growth intensity.

With the regenerative method, in addition to cement, coarse and fine aggregates and water can be heated to compensate for the heat loss during the hardening process. Heating water is a common method. Among them, the heating equipment of water is relatively simple, easy to control, and the specific heat is large, which is 5 times that of sand and gravel, so the heating of water should be considered first.

If the requirements cannot be met through thermal calculation, the heating of sand and stone materials will be considered.

When heating materials, the heating temperature of sand and stone aggregates shall not exceed 75, and the water temperature shall not exceed 90.

The water can be heated by a boiling boiler or by introducing steam directly into the tank, or by electrodes. The sand can be heated with steam, a cauldron or a hot pot.

When the temperature is -15 +5, foundation works or large volumes of concrete are suitable for this method. If the temperature is lower than -15 and the surface coefficient of the structure is greater than 6, the insulation should be strengthened, and it is best to match it with the addition of early strength agent.

Using the heat storage method, the mold temperature of concrete can be determined according to the heat dissipation of the pouring component, and the temperature of the mixture can be reversed according to the temperature of 7. According to the output temperature, the heating temperature of each material can be obtained through thermal calculation.

The constituent material of the concrete is heated and then stirred, and it still has a certain temperature after transportation and vibration, and the concrete after pouring is tightly covered with thermal insulation materials. Using this pre-added heat and the hydration heat of the cement, the concrete is cooled slowly and gradually hardened during the cooling process, and the critical strength of frost resistance or the expected strength requirement can be reached when the temperature of the concrete in the stool state drops to 0.

The heat storage method has the advantages of economy, simplicity and energy saving, and the concrete is hardened at a lower temperature, and its final strength loss is small, and the durability is higher, and a higher quality product can be obtained. However, the construction of heat storage method is slower, and the strength growth is slower, so it is advisable to choose Portland cement, ordinary Portland cement or fast-hardening Portland cement with higher strength grade and larger hydration heat. At the same time, the thermal conductivity is small, cheap and durable insulation materials.

After the insulation layer is laid, it is necessary to pay attention to moisture-proof and prevent ventilation, and the edges, ends and convex corners of the components should be particularly strengthened for thermal insulation, and the connection between the newly poured concrete and the hardened concrete, in order to avoid the conduction loss of heat, local heating measures should be taken if necessary.

Winter heat storage construction.

The heat storage method is suitable for areas where the temperature is not too cold or in the early and late winter seasons.