It is cold in winter in northern China. In order to make the temperature inside the room in winter meet the requirements of use and the needs of building energy conservation, the roof should be equipped with insulation layer.
Chinese name
Roof (top) insulation
Features
Heat insulation, fire resistance and shock absorption, simple construction, low cost
A.Thermal insulation material: Light weightporous、thermal conductivitySmall thermal insulation materials.According to the characteristics of finished insulation materials and different construction processes, insulation materials can be divided into three types: bulk materials, cast-in-place mixtures and block materials.Bulk insulation layer and cast-in-place insulation layer have good plasticity and can also be used to replace slope making layer.
(A) Bulk insulation materials: mainlyExpanded perlite、Expanded vermiculite, slag, etc.As bulk materials are easily affected by wind and other factors during construction, they are not easy to be put in place and formed, and are difficult to construct, so they are seldom used in actual projects.
（B）Cast in place insulation material: It is a thermal insulation layer cast on site by using bulk material as aggregate, mixing with cement or lime and other cementitious materials with appropriate amount of water.This kind of insulation layer has good workability, but it is still wet after it is in place, which is bad for insulation. It often needs to set vent in the insulation layer to distribute moisture, which is troublesome in structure.
(C) Plate typeThermal insulation material: MainlyPolystyrene board、Aerated concrete slab、Foam plastic board, expanded perlite slab, expanded vermiculite slab, etc.This material has the advantages of fast construction speed, good thermal insulation effect and avoiding wet work, and is widely used in engineering.If possible, it is better to use more than two layers of plates to form an insulation layer, and deal with the joints between plates to avoid thermal bridge.
B. Location of insulation layer
(A) The thermal insulation layer is located between the structural layer and the waterproof layer: this is the most commonly used method. The thermal insulation layer is located on the low-temperature side of the roof system, which has good thermal insulation effect and conforms to the thermal principle. At the same time, since the thermal insulation layer is paved on the structural layer, which conforms to the principle of stress, the structure is also simple.
In order to prevent the water vapor in the indoor air from rising with the hot airflow and entering the insulation layer through the structural layer, thus reducing the insulation effect, a vapor barrier should be set below the insulation layer.Generally, the vapor barrier is paved with one felt and two oils (one layer of hot asphalt) on the leveling layer or connected with the roofWaterproof materialThe same coiled material (thickness can be thinner) shall be processed.
(B) The thermal insulation layer is set above the waterproof layer: this method is also called "inverted thermal insulation roof", and its structural layers are thermal insulation layer, waterproof layer and structural layer.This kind of house face adoptsThermal insulation materialIf there are special requirements, hydrophobic materials with low moisture absorption and strong weather resistance should be used as the insulation layer (such asPolystyrene foamBoard or polychlorinated foam plastic board), and addreinforced concrete, pebble, brick and other heavy overburden.
(C) Combination of thermal insulation layer and structural layer: this thermal insulation method is relatively rare, and there are mainly two methods:reinforced concreteThermal insulation layer is set in the trough plate;The other is to setThermal insulation materialIntegration with structure, such as reinforcementAerated concrete slab。This method enables the roof panel to have the dual functions of structural layer and insulation layer at the same time, simplifies the process and reduces the construction cost.
2 Insulation of pitched roof
The insulation layer of pitched roof is similar to that of flat roof, and the insulation structure is not much different from that of flat roof.The thermal insulation layer can be located not only above the roof structure layer (commonly known as upper chord thermal insulation), but also below the structure layer (commonly known as lower chord thermal insulation).
Construction process
Announce
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1 Preface
Structural drawing of roof insulation
With the development of social economy, the energy problem has become increasingly serious from the perspective of the overall international economic climate and China's macroeconomic trend. Building energy consumption has accounted for 27.8% of the total national energy consumption, so energy conservation is imperative. The country has formulated a series of measures and regulations for energy conservation and emission reduction accordingly.Building materials with the concept of energy conservation and environmental protection are increasingly supported by the state and favored by the marketFoam concreteAs a new type of thermal insulationThermal insulation materialBecause of its obvious thermal insulation effect, fire resistance and shock absorption, simple construction and low cost, it has gradually become one of the preferred materials for building roof insulation and slope making.The construction technology is summarized through engineering practice.
2 Construction method characteristics
Foam concreteIt has the characteristics of light weight, low elasticity, heat insulation, fire resistance and shock absorption, high integrity and durability, good waterproof effect, etc. Its construction process does not require any vibration, which can reduce labor intensity, and is cheap in cost, environmental protection and economy.
3 Scope of application
This method is applicable to general industry andCivil buildingsConstruction of slope making and thermal insulation layer of the flat roof of the project.Its structure is shown in Figure 1,
Figure 1 Schematic Diagram of Roof Waterproof and Heat Insulation Sloping Structure
Or refer to the standard atlas.
4 Process principle
Foamed concrete is a kind of lightweight concrete, which is made by adding and pressing the foam water solution to form a foam composed of evenly closed bubbles by mechanical method, and then injecting the foam into the slurry made of cement, aggregates, admixtures, water and various admixtures, and then mixing, casting and curingporous material 。
5 Process Flow and Key Points of Operation
5.1 Construction process
See Figure 5.1 for the process flow.
Watering and curing for 14 daysFoam concreteBefore and after final setting, take out the dividing strip in time and cut the dividing joint and fill the dividing joint with sealing paste for acceptance. According to the design requirements, add foaming agent, water and additives into the foaming bottle through test to determine the mix ratio, and add them into the mixer to mix and pressurize to form foam crystal cementSand is added to the mixer, mixed and mixed to form foam concrete. The foam concrete is paved on the surface of the construction site. The base course is scraped and watered as required. The cement slurry is applied. The dividing strip is buried at specific locations. The elevation is controlled. The line is used for slope making
Figure 5.1 Process Flow Diagram
5.2 Key points of operation
5.2.1 Trial mix foam concrete according to design requirements, and determine the amount of cement, foaming agent, water, aggregate and admixture.
5.2.2 Clean the dust, sundries and ponding on the base course.
5.2.3 According to the design thickness and slope of foam concrete layercement mortarStick the elevation of the point (stick the ash cake), then pull the line and screed.If there is no specified slope value in the design, the slope value should be 2%.
5.2.4 At the junction of the roof and parapet and around the structure protruding from the roof, the dividing strip shall be buried.
5.2.5 Spray water on the base course for wetting, and then brush a layer of plain cement slurry.
5.2.6 Add foaming agent and water with foaming dosage of 12~13 times into the foaming bottle, inflate and pressurize for 3~6 minutes, and stop the machine for standby after the air pressure of the air compressor rises to 0.6~0.8MPa.
5.2.7 Add water and tensile fiber (0.7 kg/m) into the mixer and mix for 1~2 minutes, then add cement, sand and additives in the mixer in order to mix for 2~3 minutes to form thick thick liquid, and then add the foam described in 5.2.6 to mix.When the foam in the mixerConcrete slumpWhen it increases to 200~220mm, stop adding foam after reaching the design cubic weight ratio, and then continue to mix the foam concrete for 5~6 minutes.Then pour the evenly mixed finished foam concrete onto the foundation.
5.2.8 The foam concrete shall be paved in a sectional flow process, the virtual paving thickness shall be 1.2~1.3 times of the actual thickness, and then the aluminum alloy scraper with a length of 3 meters shall be used for leveling.
5.2.9 OnFoam concreteWhen approaching the final setting, the grid strips buried around the protruding parts of the roof and the parapet wall shall be taken out first;After the final setting of the foam concrete, the cutting machine shall be used to cut the dividing joints in time. The spacing of the dividing joints should be 3m × 3m, and the width of the dividing joints should be reserved as 25mm. The depth is the same as the thickness of the foam concrete laid. After the curing period, the dividing joints should be filled with PVC senior sealant.
5.2.10 The foam concrete shall be watered for curing 24 hours after construction, and the curing time shall not be less than 14 days.During the curing period, try to avoid people walking on it and prohibit stacking objects, so as not to damage the bubble structure and affect the heat insulation effect.
5.3 Labor organization
The labor organization shall be determined according to the number of equipment groups and the divided working face and flow section. Take the construction personnel allocation required by a group of equipment as an example. See Table 5.3 for the required personnel allocation.
Table 5.3 Staffing and work tasks of various types of work
S/N
Type of work
Number of people
Task
one
General workers
three
Add construction materials into the mixer and foam bottle,
Transportation of finished foam concrete
two
Machine operator
two
Operate the foam bottle and mixer, and cut the dividing seam
three
Slurry technician
one
Spread, trowel and polish foam concrete
four
commander
(Foreman)
one
Organize command, scheduling and process arrangement
6.1.2 Sand: either ordinary river sand or mountain sand, with silt content less than 3%.
6.1.3 Shrinkage compensation agent: generally Cao-Al2O3-CaSO4, which can effectively improveFoam concreteCrack resistance.
6.1.4 Foaming agent: the main raw materials are pollution-free animal protein oil and vegetable oil, which will not have any negative effects on producers, users and the environment.It is characterized by fast foaming speed, uniform foam, tough liquid film, good stability, low bleeding rate, long duration, and no impact on cementitious materials.
6.1.5 All materials shall be provided with factory certificate, factory performance report, product instructions, etc., and relevant mobilization inspection shall be carried out according to regulations.
six point twoequipment
The required machines and equipment include: foam bottleMortar mixerFG50 air cooling seriesAir compressor(including pressure gauge), level gauge, tape measure, shovel, slump cylinder, aluminum alloy scraper, wood trowel, cutting machine, etc.
FG50 air cooling seriesAir compressorSee Table 6.2 for technical parameters.
Table 6.2 Technical Parameters of FG50 Air cooled Series Air Compressor
FG50
-
-
-
-
Air displacement (m3/min)
Exhaust pressure (Mpa)
Power (Kw)
Cylinder diameter (mm) × number of cylinders
Air reservoir volume (L)
zero point four eight
zero point seven
four
80×3
one hundred and thirty
7 Quality control
7.0.1Foam concreteThe mix proportion of shall be determined by test according to the design standard strength, construction conditions and ambient temperature.All raw materials shall meet the quality requirements and the measurement shall be strictly controlled.(See Table 7.1 for common mix proportion)
Table 7.1 Common Mix Proportion of Foam Concrete (kg/m3)
Cement (42.5R)
Medium coarse sand
foaming agent
(Patent)
Formula
(Patent additive)
water
three hundred and fifty
300~500
three
1～1.5
appropriate amount
(The dosage is controlled by slump)
Note: This table takes foam concrete with unit weight of 700~900kg/m3 as an example, and the slump is 200~220mm
7.0.2 The dry unit weight of foam concrete is 500~1000kg/m, and the thermal conductivity is ≤ 0.22w/m.k.The unit weight, drying shrinkage value and compressive strength shall be in accordance with Test Methods for Small Concrete Hollow Blocks (GB/T4111-1997), the water absorption shall be in accordance with Test Methods for Bulk Density, Moisture Content and Water Absorption of Aerated Concrete (GB/T11970-1997), and the thermal conductivity shall be in accordance with the relevant provisions of Thermal Insulation Materials Determination of Steady State Thermal Resistance and Related Properties Protective Heat Method (GB/T10294-88).
7.0.4 The thickness of integral cast-in-place roof foam concrete shall not be less than 60mm, and the reserved area of dividing joint shall not be more than 4m × 4m. The dividing joint shall be appliedFlexible waterproof materialInfilling;The gradient must be accurate and meet the design requirements, and no back flashing is allowed.
7.0.5 The surface of large-area foam concrete shall be flat, and checked with a 2m guiding rule. The gap shall not be greater than 5mm, and there shall be no looseness, sanding, peeling, etc.
7.0.6 No construction is allowed in rainy and snowy days or in the weather with force five wind or above, and the ambient temperature for construction should be between 5 ℃ and 40 ℃.
8 Safety measures
When using this construction method, in addition to the provisions on safety construction, the following matters shall also be observed:
8.0.1 Construction operators must understand and master the technical operation essentials of this process, and special types of work (mechanical operators, etc.) should be employed with certificates.
8.0.2Foam concreteBefore productionAir compressor, foam bottle, mixer, etc., and can be started up after the test run is normal.
8.0.3 During construction, pay attention to the value of the pressure gauge at any time, and it is strictly prohibited to exceed the pressure limit.The air compressor and foam bottle shall be operated in strict accordance with the operating procedures and sequence to prevent the air flow pipe of the air compressor from rebounding and hurting people.
9 Environmental requirements
9.0.1 When adding materials, construction personnel must wear masks and other protective equipment.
9.0.2 ReductionAir compressorNoise and vibration of mixer or take corresponding isolation measures.The rest time of residents shall be avoided during construction.
9.0.3 Foam concrete is made on site, and all materials should be kept in a unified way. The remaining materials should not be discarded at will, especially various admixtures and foaming agents should be timely put away and properly kept after the completion of the process.
