Construction method number: RJGF (minimum)-10-2008
Completed by: China Construction No.7 Bureau No.3 Company
Main Accomplishers: Gao, Xie Congming and Liu Jiangbo.
1 preface
With the development of social economy, the energy problem has become increasingly serious, no matter from the whole international economic climate or the macro-economic trend of China. Building energy consumption has accounted for 27.8% of China's total energy consumption, so energy conservation is imperative. Accordingly, the state has formulated and promulgated a series of measures and regulations for energy conservation and emission reduction. In recent years, building materials with the concept of energy conservation and environmental protection are increasingly supported by the state and favored by the market. As a new type of thermal insulation material, foam concrete has gradually become one of the first choice materials for building roof thermal insulation and slope finding because of its obvious thermal insulation effect, fire prevention and shock absorption, simple construction and low cost. Its construction technology is formed through the summary of engineering practice.
2 characteristics of construction methods
Foamed concrete has the characteristics of light weight, low elasticity, heat insulation, fire prevention and shock absorption, high integrity and durability, and good waterproof effect. Its construction process does not need any vibration, which can reduce the labor intensity, and its cost is low, environmental protection and economy.
3 Scope of application
This method is suitable for the construction of slope-finding insulation layer of flat roof in general industrial and civil construction projects. Its structure is shown in Figure 3.
Fig. 3 Schematic diagram of roof waterproof and thermal insulation slope finding structure
4 process principle
Foamed concrete is a kind of light porous material, which is made by mechanically pressurizing aqueous foam solution into uniform and closed bubbles, then injecting foam into slurry made of cement, aggregate, admixture, water and various additives, and then mixing, stirring, pouring, molding and curing.
5 process flow and operation points
5. 1 construction process
The process flow is shown in Figure 5. 1.
5.2 Key points of operation
5.2. 1 According to the design requirements, try to mix foamed concrete and determine the dosage of cement, foaming agent, water, aggregate and admixture.
5.2.2 Clean the dust, sundries and accumulated water on the pedestal.
5.2.3 According to the design thickness and slope of the foam concrete layer, paste the elevation with cement mortar (paste the ash cake), and then stay and screed. If the slope value is not specified in the design, the slope value should be 2%.
5.2.4 Frame reinforcement shall be buried at the junction of the roof and parapet and around the structures protruding from the roof.
5.2.5 Sprinkle water on the base for wetting, and then brush with plain cement slurry.
5.2.6 Add foaming agent and water with foaming dosage of 65,438+02 ~ 65,438+03 times to the foaming bottle, inflate and pressurize for 3 ~ 6 minutes, and then stop the air compressor for standby after the air pressure rises to 0.6 ~ 0.8 MPa.
5.2.7 Add water and tensile fiber (0.7kg/m3) into a blender and stir for 1 ~ 2 minutes, then add cement, sand and additives into the blender and stir for 2 ~ 3 minutes to form a thick solution, and then add the foam formed in 5.2.6 to stir. When the slump of foamed concrete in the mixer increases to 200 ~ 220 mm, stop adding foam after reaching the designed cubic weight ratio, and then continue mixing foamed concrete for 5 ~ 6 minutes. Then pour the evenly stirred finished foam concrete onto the foundation beam.
5.2.8 Foam concrete shall be paved by sectional flow operation, and the virtual paving thickness shall be 1.2 ~ 1.3 times of the actual thickness, and then it shall be leveled with 3m-long aluminum alloy scraping bar.
5.2.9 When the foamed concrete is close to the final setting, take out the frame bars buried around the protruding part of the roof and parapet; After the final set of foamed concrete, cut the frame joints with a cutting machine in time. The spacing of frame joints is 3m×3m, the width of frame joints is 25mm, and the depth is the same as the laying thickness of foam concrete. After the curing period, PVC advanced sealant should be embedded in the frame joints.
5.2. 10 foam concrete shall be watered and cured 24 hours after construction, and the curing time shall not be less than 14 days. During the curing period, people should be prevented from walking on it, and articles should not be piled up, so as not to destroy the bubble structure and affect the thermal insulation effect.
5.3 Labor Organization
The labor organization should be determined according to the number of equipment groups and the divided working face and flow section. Take the construction workers needed for a group of equipment as an example. See table 5.3 for the required personnel.
Table 5.3 Staffing and tasks of each type of work
Number of jobs, number of people and tasks
1 pu gong 3 add building materials into the blender and foaming bottle.
Transport finished foam concrete
Mechanical operators 2 operate foaming bottles and mixers to cut frame joints.
3 Mud mechanic 1 Spread, smooth and collect the foamed concrete.
Four commanders
(foreman) 1 Organization, command, scheduling and process arrangement
5 handyman 1 site cleaning and maintenance
6 materials and equipment
6. 1 material
6. 1. 1 cement: ordinary portland cement, slag portland cement and fly ash portland cement with P.O. above P.O.32.5R can be used.
6. 1.2 sand: ordinary river sand or mountain sand can be used, and the silt content should be less than 3%.
6. 1.3 shrinkage compensator: generally Cao-Al2O3-CaSO4, which can effectively improve the crack resistance of foamed concrete.
6. 1.4 foaming agent: the main raw materials are pollution-free animal protein oil and vegetable oil, which will not have any negative impact on producers, users and the environment. It is characterized by fast foaming speed, uniform foam, tough liquid film, good stability, low bleeding rate and long duration, and has no influence on cementing materials.
6. 1.5 Materials shall have factory certificate, factory performance report, product manual, etc. , and carry out relevant entry inspection as required.
6.2 equipment
The required machines and equipment include: foaming bottle, mortar mixer, FG50 air-cooled series air compressor (including pressure gauge), level gauge, tape measure, shovel, slump cone, aluminum alloy scraper, wood trowel, cutting machine, etc.
See Table 6.2 for the technical parameters of FG50 air-cooled series air compressors.
Table 6.2 Technical Parameters of FG50 Air-cooled Series Air Compressor
FG50
Displacement (m3/min), exhaust pressure (Mpa), power (Kw), cylinder diameter (mm)× number of cylinders, cylinder volume (L)
0.48 0.7 4.0 80×3 130
7 quality control
7.0. 1 The mixture ratio of foamed concrete shall be determined by tests according to the design standard strength, construction conditions and ambient temperature. All kinds of raw materials should meet the quality requirements, and the measurement should be strictly controlled. (See Table 7 for common mix proportion.1)
Table 7. 1 Common Mix Proportion of Foam Concrete (kg/m3)
Foaming agent for coarse sand in cement (42.5R)
(patented) formula
(patented additive) water
350 300 ~ 500 3 1 ~ 1.5 fitness
(dosage is controlled by slump)
Note: This table takes foamed concrete with bulk density of 700 ~ 900 kg/m3 as an example, with slump of 200 ~ 220 mm 。
7.0.2 The dry bulk density of foamed concrete is 500 ~ 1000 kg/m3, and the thermal conductivity is ≤ 0.22 w/m.k Its bulk density, dry shrinkage and compressive strength conform to the Test Method for Small Concrete Hollow Blocks (GB/T 411/kloc).
7.0.3 The construction and quality acceptance of roof foam concrete shall comply with Technical Specification for Roof Engineering (GB50345-2004), Quality Acceptance Standard for Roof Engineering (GB50207-2002) and Quality Acceptance Standard for Building Energy Saving Engineering (GB 5041KLOC-0/-2007).
7.0.4 The thickness of integral cast-in-place roof foam concrete shall not be less than 60mm, and the retained area of frame joints shall not be greater than 4m×4m, and the frame joints shall be filled with flexible waterproof materials; Its slope must be accurate and meet the design requirements, and it is not allowed to pour water.
7.0.5 The surface of large-area foamed concrete shall be smooth, and it shall be checked by 2m guiding rule. The clearance shall not be greater than 5mm, and there shall be no looseness, sand and peeling.
7.0.6 No construction is allowed in rainy and snowy days or windy weather with magnitude 5 or above, and the construction environment temperature should be between 5℃ and 40℃.
8 safety measures
When using this method for construction, in addition to observing the provisions of safe construction, the following items should also be observed:
8.0. 1 Construction workers must understand and master the technical operation essentials of this technology, and special types of work (mechanical operators, etc. ) should hold relevant certificates.
8.0.2 Before making foamed concrete, check the air compressor, foaming bottle and mixer. , start after the trial operation is normal.
8.0.3 During construction, always pay attention to the value of pressure gauge, and it is forbidden to exceed the standard. And operate the air compressor and foaming bottle in strict accordance with the operating rules and sequence to prevent the air flow tube of the air compressor from rebounding and hurting people.
9 environmental protection requirements
9.0. 1 When adding materials, the construction personnel must carry protective articles such as masks.
9.0.2 Noise and vibration of air compressor and mixer should be reduced, or corresponding isolation measures should be taken. During construction, residents' rest time should be avoided.
9.0.3 The foamed concrete shall be produced on site, and all materials shall be kept in a unified way. The remaining materials shall not be discarded at will, especially all kinds of additives and foaming agents shall be put away in time after processing.
Benefit analysis of 10
10.0. 1 Compared with other roof insulation slope-finding layers (such as cement mortar slope-finding and extruded insulation board, expanded perlite, ceramsite concrete, overhead prefabricated insulation board, etc.), foam concrete has the advantages of light weight, simple process, few working procedures, good waterproof and thermal insulation effect, economy and environmental protection, and good comprehensive benefits.
10.0.2 Taking Fuzhou Vientiane Commercial Plaza as an example, compared with the commonly used cement mortar and extruded insulation board, the benefit analysis is as follows: (Except foam concrete is a new building material, the unit price is not reflected in the quota, and other unit prices are calculated according to the quota of Fujian Province in 2005).
1 slope insulation with foam concrete. The thickest part of the roof 150mm, the thinnest part 60mm, and the average thickness 100mm. At present, the comprehensive unit price per cubic meter of foam concrete market is 250 yuan /m3, that is, the unit price per square meter of 100 mm thickness is 25 yuan.
2 cement mortar slope, according to the design requirements, the slope is 65438 0%, with an average thickness of 25mm. According to the quota, the unit price of 25mm thick cement mortar screed-coat is 10.72 yuan per square meter.
Unit price per square meter of 25mm thick extruded insulation board 19.4438+0 yuan /m2.
Therefore, the unit price of cement mortar and extruded insulation board as thermal insulation slope layer per square meter is:
10.72+19.41= 30.13 yuan/m2
Compared with cement mortar, extruded insulation board and foamed concrete, the cost per square meter is saved by 30. 13-25 = 5. 13 yuan.
The roof area of Vientiane Commercial Plaza is calculated as16000m2, and the * * cost saving is 5. 13× 16000 = 66080 yuan.
1 1 engineering example
Roof foam concrete construction technology has been widely used in many projects undertaken by our company, such as Jinjiang Baolong Hotel and Fuzhou Vientiane Commercial Plaza. The practical application effect is remarkable, which brings good comprehensive benefits to the company.
1 1.0. 1 Fuzhou Vientiane Commercial Plaza Project is recommended to be declared as Fuzhou Science and Technology Demonstration Project; The construction area is100633m2, of which the roof construction area is about16000m2. The design requires that the roof insulation slope-finding layer adopts foam concrete, with a slope of 1% and a minimum thickness of 60mm. It took only 5 days to complete the construction of all roof foam concrete, saving 66,080 yuan in engineering cost. No common quality problems such as cracking and leakage have been found in the past year, and the insulation effect is obvious. Deeply praised by the owners and settled merchants.
1 1.0.2 Jinjiang Baolong Hotel is a five-star hotel. The building area is 50,000 ㎡, of which the building area of podium roof is about 3,800 ㎡, and the insulation layer is foam concrete. The thinnest part of this layer is 70mm, the slope is 65438 0.5%, and the bulk density of foamed concrete is 800kg/m3. Through several years of observation, the actual effect is good, especially in terms of thermal insulation comparison.
Practice has proved that it is of great significance to popularize the application of this method in roof insulation and slope finding to reduce project cost, save energy and protect environment and improve roof quality.