GB 50208: Evolution and historical versions
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Code for acceptance of construction quality of underground waterproof
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Code for Acceptance of Construction Quality of Underground Waterproof
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Basic data | Standard ID | GB 50208-2011 (GB50208-2011) | | Description (Translated English) | Code for acceptance of construction quality of underground waterproof | | Sector / Industry | National Standard | | Classification of Chinese Standard | P18 | | Classification of International Standard | 93.020 | | Word Count Estimation | 175,195 | | Date of Issue | 2011-04-02 | | Date of Implementation | 2012-10-01 | | Older Standard (superseded by this standard) | GB 50208-2002 | | Quoted Standard | GB 50046; GB/T 50080; GB/T 50081; GB/T 50082; GB/T 50107; GB 50119; GB 50204; GB 50300; GB 50476; GB/T 18046; JGJ 63; JC 1066 | | Regulation (derived from) | Bulletin of the Ministry of Housing and Urban No. 971 | | Issuing agency(ies) | Ministry of Housing and Urban-Rural Development of the People's Republic of China; General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China | | Summary | This Chinese standard applies to building construction, protection works, municipal tunnels, subways and other underground works quality acceptance. | GB 50208-2011: Code for acceptance of construction quality of underground waterproof---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
1 General
1.0.1 In order to strengthen the quality management of construction projects, unify the quality acceptance of underground waterproof projects, and ensure the quality of projects, this specification is formulated.
1.0.2 This code is applicable to the quality acceptance of underground waterproofing works such as housing construction, protection works, municipal tunnels, and underground railways.
1.0.3 New technologies used in underground waterproofing projects must pass the identification and evaluation of scientific and technological achievements or the identification of new products and new technologies. Before the application of new technology, the new or first adopted construction technology shall be reviewed and corresponding technical standards shall be formulated.
1.0.4 The construction of underground waterproofing works shall comply with the current national regulations on safety, labor protection and environmental protection.
1.0.5 The quality acceptance of underground waterproofing works shall not only comply with this specification, but also comply with the current relevant national standards.
2 terms
2.0.1 underground waterproof project
An engineering entity that performs various technical work such as waterproof design, waterproof construction, maintenance and management of housing construction, protective engineering, municipal tunnels, underground railways and other underground projects.
2.0.2 cut and cover method
Open excavation of foundation pits, then build underground works in the foundation pits, and finally backfill with earth and rocks.
2.0.3 subsurface excavation method
The construction method of tunnels and other underground works is constructed by excavating, supporting and lining underground from the construction passage without digging the ground.
2.0.4 cementitious material or binder
The general term for mineral admixtures such as Portland cement and fly ash, ground slag, and silica fume used to prepare concrete in the factory.
2.0.5 water to binder ratio
The ratio of water consumption in concrete preparation to the total amount of cementitious materials.
2.0.6 bolt-shotcrete support
A form of surrounding rock support combined with bolts and reinforced mesh shotcrete.
2.0.7 Underground diaphragm wall underground diaphragm wall
The mechanical construction method is used to form grooves and pour reinforced concrete to form an underground wall with the functions of water interception, seepage prevention, soil retaining and load bearing.
2.0.8 shield tunneling method
The full-section excavation of the shield tunneling machine is adopted, and the reinforced concrete segment is used as the lining support for the tunnel constructed by the underground excavation method.
2.0.9 open caisson
The wellbore is composed of the blade foot, the well wall and the partition wall. The soil is excavated in the shaft to make it sink, and the concrete bottom is sealed after reaching the design elevation.
2.0.10 Inverted construction
The main structure is that the underground diaphragm wall doubles as the wall and the concrete pouring pile doubles as the load-bearing column, and the roof, mid-floor and bottom slab are constructed from top to bottom.
2.0.11 Inspection lot inspection lot
A test object composed of a certain number of samples that is collected for inspection under the same production conditions or in a prescribed manner.
2.0.12 witness sampling test evidence testing
Under the supervision of the supervision unit or the witnesses of the construction unit, the sampler of the construction unit will take samples on site and send them to the testing unit with corresponding qualifications for testing.
3 basic rules
3.0.1 The waterproof grade standard of underground works shall comply with the provisions in Table 3.0.1.
Table 3.0.1 Waterproof grade standards for underground works
3.0.2 The waterproof fortification of underground works with open cut method and underground method shall be selected according to Table 3.0.2-1 and Table 3.0.2-2.
Table 3.0.2-1 Waterproof fortification of underground works by open cut method
Table 3.0.2-2 Waterproofing and Defense of Underground Engineering by Underground Excavation
3.0.3 Underground waterproofing works must be carried out by professional waterproofing teams holding qualification grade certificates, and the main construction personnel should hold professional qualification certificates or waterproofing professional post certificates issued by provincial and above construction administrative departments or their designated units.
3.0.4 Before the construction of the underground waterproof project, the joint review of the drawings should be conducted to grasp the waterproof requirements of the main structure and the detailed structure. The construction unit should prepare a special construction plan for the waterproof project, which will be implemented after being reviewed and approved by the supervisory unit or the construction unit.
3.0.5 The varieties, specifications and performance of waterproof materials used in underground engineering must comply with the current national or industry product standards and design requirements.
3.0.6 Waterproof materials must be sampled and inspected by a testing unit with corresponding qualifications, and a product performance testing report shall be issued.
3.0.7 The entry acceptance of waterproof materials shall comply with the following regulations.
1 Check and accept the appearance, variety, specification, packaging, size and quantity of the materials, and form the corresponding acceptance records after being checked and confirmed by the supervisory unit or the representative of the construction unit;
2 Check the quality certification documents of the materials, and after being checked and confirmed by the supervisory unit or the representative of the construction unit, include them in the engineering technical files;
3 After entering the site, the materials shall be sampled and inspected according to the provisions of appendix A and appendix B of this specification. The inspection shall implement the witness sampling and inspection system, and issue the material entry inspection report;
4 When all the indicators of the physical performance test items of the material meet the standard requirements, it is qualified; if one indicator does not meet the standard requirements, re-sampling should be carried out in the inspected product for re-inspection of the indicators, and the re-inspection results meet the standard requirements, then This batch of materials is judged to be qualified.
3.0.8 The waterproof materials and supporting materials used in underground works shall comply with the current industry standard "Limits of Hazardous Substances in Building Waterproof Coatings" JCl066, and shall not cause pollution to the surrounding environment.
3.0.9 For the construction of underground waterproofing works, a system of self-inspection, handover inspection and full-time personnel inspection of each process shall be established, and a complete inspection record shall be established; before the project is concealed, the construction unit shall notify the relevant unit for acceptance and form Concealed project acceptance records; without the inspection and confirmation of the supervisory unit or the representative of the construction unit on the previous process, the construction of the next process shall not be carried out.
3.0.10 During the construction of the underground waterproofing project, the groundwater level must be kept stable below the lowest elevation of 500mm at the bottom of the project, and precipitation measures should be taken when necessary. For foundation pits using ditch drainage, the foundation pit should be kept dry.
3.0.11 Underground waterproofing works shall not be constructed in rainy days, snowy days, and winds of Grade 5 and above; the environmental temperature conditions for construction of waterproof materials should comply with the provisions in Table 3.0.1l.
Table 3.0.11 Air temperature conditions of construction environment of waterproof materials
Table 3.0.12 Sub-projects of Underground Waterproofing Works
3.0.13 Sub-project inspection batches and sampling inspection quantities of underground waterproofing works shall meet the following requirements.
1 The main structure waterproofing project and the detailed structure waterproofing project shall be divided into inspection batches according to the construction sections such as structural layers, deformation joints or post-pouring belts;
2 The special construction method structural waterproofing project shall be divided into inspection batches according to the construction sections such as tunnel sections and deformation joints;
3 Drainage works and grouting works shall each be an inspection lot;
4 Sampling inspection quantity of each inspection batch. the detailed structure should be fully inspected, and the others should comply with the provisions of this specification.
3.0.14 The underground works shall be checked and accepted according to the designed waterproof level standard. The investigation and detection of water seepage in underground works shall be carried out in accordance with Appendix C of this code.
4 Waterproofing of the main structure
4.1 Waterproof concrete
4.1.1 Waterproof concrete is suitable for underground concrete structures with impermeability grade not less than P6.Not suitable for underground projects where the ambient temperature is higher than 80°C. In an aggressive medium, the corrosion resistance requirements of waterproof concrete should meet the relevant provisions of the current national standards "Code for Anti-corrosion Design of Industrial Buildings" GB 50046 and "Code for Durability Design of Concrete Structures" GB 50476.
4.1.2 The selection of cement shall meet the following requirements.
1 Ordinary Portland cement or Portland cement should be used, and other types of cement should be determined through experiments;
2 When it is affected by erosive media, the corresponding cement varieties should be selected according to the nature of the media;
3 Do not use expired or damp-caking cement, and do not mix cement of different varieties or strength grades.
4.1.3 The selection of sand and stone should meet the following requirements.
1 The sand should be medium-coarse sand, and the mud content should not be greater than 3.0%. The mud content should not be greater than 1.0%;
2.It is not suitable to use sea sand; when there is no condition for using river sand, sea sand should be treated before use, and the content of chloride ions should not be greater than 0.06%;
3 The particle size of crushed stone or pebble should be 5mm~40mm. The mud content should not be greater than 1.0%, and the mud content should not be greater than 0.5%;
4 The sand and stone used in concrete for important structures that have been in a humid environment for a long time should be tested for alkali activity.
4.1.4 The selection of mineral admixtures should meet the following requirements.
1 The grade of fly ash should not be lower than grade II, and the loss on ignition should not be greater than 5%;
2 The specific surface area of silicon powder should not be less than 15000m2/kg, and the SiO2 content should not be less than 85%
3 The quality requirements of granulated blast furnace slag powder should meet the relevant provisions of the current national standard "Granulated Blast Furnace Slag Powder Used in Cement and Concrete" GB/T 18046.
4.1.5 Concrete mixing water shall comply with the relevant provisions of the current industry standard "Concrete Water Standard" JGJ 63.
4.1.6 The selection of admixtures should meet the following requirements.
1 The type and dosage of admixtures should be determined by tests, and the admixtures used should meet the quality requirements of the current national standard "Technical Specifications for the Application of Concrete Admixtures" GB 50119;
2 The air content of concrete mixed with air-entraining agent or air-entraining water reducer should be controlled at 3% to 5%;
3 Consider the influence of admixtures on the shrinkage properties of hardened concrete;
4 It is strictly forbidden to use admixtures that are harmful to the human body and pollute the environment.
4.1.7 The mix ratio of waterproof concrete shall be determined through tests and shall meet the following requirements.
l The anti-seepage pressure value required for trial assembly should be 0.2MPa higher than the design value;
2 The total amount of cementitious materials in concrete should not be less than 320kg/m3, of which the amount of cement should not be less than 260kg/m3, the amount of fly ash should be 20% to 30% of the total amount of cementitious materials, and the amount of silica fume should be 2% to 5% of the total amount of materials;
3 The water-binder ratio shall not be greater than 0.50, and the water-binder ratio should not be greater than 0.45 when there is an aggressive medium;
4 The sand rate should be 35% to 40%, and it can be increased to 45% during pumping;
5 The ratio of lime to sand should be 1.1.5～1.2.5;
6 The chloride ion content of the concrete mixture should not exceed 0.1% of the total amount of cementitious materials; the total alkali content of various materials in the concrete, that is, the Na2O equivalent, should not exceed 3kg/m3.
4.1.8 When ready-mixed concrete is used for waterproof concrete, the slump of the pump should be controlled at 120mm to 160mm, the loss of slump per hour should not be greater than 20mm, and the total loss of slump should not be greater than 40mm.
4.1.9 The process control of concrete mixing and pouring shall comply with the following regulations.
1 The type, specification and dosage of materials used in concrete mixing shall be inspected no less than twice per working shift. The allowable deviation of the measurement results of each concrete composition material shall comply with the provisions in Table 4.1.9-1.
Table 4.1.9-1 Allowable Deviation of Concrete Composition Material Measurement Results (%)
Note. Accumulative metering is only applicable to computer-controlled metering and mixing stations.
2 The slump of concrete at the pouring site shall be inspected at least twice per work shift, and the slump test shall comply with the relevant provisions of the current national standard "Standards for Test Methods of Performance of Ordinary Concrete Mixtures" GB/T 50080.The allowable deviation of concrete slump shall comply with the provisions in Table 4.1.9-2.
Table 4.1.9-2 Allowable Deviation of Concrete Slump (mm)
3 The slump of the pumped concrete at the delivery site shall be checked at least twice per work shift. The allowable deviation of slump when concrete is pumped shall comply with the provisions in Table 4.1.9-3.
Table 4.1.9-3 Allowable deviation of slump when concrete enters the pump (mm)
4 When the waterproof concrete mixture is segregated after transportation, secondary mixing must be carried out. When the slump loss cannot meet the construction requirements, the cement slurry with the original water-to-binder ratio or the same type of water reducing agent should be added for stirring, and it is strictly forbidden to add water directly.
4.1.10 The compressive strength test piece of waterproof concrete shall be made after random sampling at the concrete pouring site, and shall meet the following requirements.
1 For the concrete of the same project and the same mix ratio, the sampling frequency and the number of test specimen retention groups shall comply with the relevant provisions of the current national standard "Code for Construction Quality Acceptance of Concrete Structure Engineering" GB 50204;
2 The compressive strength test shall comply with the relevant provisions of the current national standard "Standard for Test Methods of Mechanical Properties of Ordinary Concrete" GB/T 50081;
3 Concrete strength evaluation of structural components shall comply with the relevant provisions of the current national standard "Concrete Strength Inspection and Evaluation Standard" GB/T 50107.
4.1.11 The impermeability of waterproof concrete shall be evaluated by the test results of the impermeability test specimens of cured concrete under standard conditions. The test specimens shall be made after random sampling at the concrete pouring site, and shall meet the following requirements.
1 For every 500m3 of continuous pouring concrete, a group of 6 anti-seepage test pieces shall be left, and each project shall not be less than two sets; for the anti-seepage test piece of ready-mixed concrete, the number of left groups shall be determined according to the scale and requirements of the structure;
2 The impermeability test shall comply with the relevant provisions of the current national standard GB/T 50082 "Standard for Test Methods of Long-term Performance and Durability of Ordinary Concrete".
4.1.12 For the construction of large-volume waterproof concrete, technical measures such as material selection, temperature control, heat preservation and moisture retention shall be adopted. If the design permits, the age of design strength grade of fly ash concrete should be 60d or 90d.
4.1.13 The number of samples to be inspected for the inspection batch of waterproof concrete sub-projects shall be 1 spot for every 100m2 exposed area of concrete, and each spot shall be 10m2, and shall not be less than 3 spots.
Ⅰ Master Control Item
4.1.14 The raw materials, mix ratio and slump of waterproof concrete must meet the design requirements. Inspection method. Check the product certificate, product performance test report, measurement measures and material entry inspection report.
4.1.15 The compressive strength and impermeability of waterproof concrete must meet the design requirements. Inspection method. check the concrete compressive strength, impermeability performance inspection report.
4.1.16 The setting and structure of construction joints, deformation joints, post-casting strips, wall pipes, and embedded parts of waterproof concrete structures must meet the design requirements.
Inspection method. observation inspection and inspection of concealed project acceptance records
Ⅱ General Items
4.1.17 The surface of the waterproof concrete structure should be solid and flat, without defects such as exposed ribs and honeycombs; the position of the embedded parts should be accurate.
Inspection method. observation inspection.
4.1.18 The crack width on the surface of the waterproof concrete structure should not be greater than 0.2mm, and must not penetrate.
Inspection method. check with a graduated magnifying glass.
4.1.19 The thickness of the waterproof concrete structure should not be less than 250mm, and its allowable deviation should be 8mm, -5mm;
Inspection method. scale inspection and inspection of concealed project acceptance records.
4.2 Cement mortar waterproof layer
4.2.1 The cement mortar waterproof layer is applicable to the water-facing surface or the back-water surface of the main structure of the underground project. Not suitable for underground projects subject to continuous vibration or ambient temperature higher than 80°C.
4.2.2 The cement mortar waterproof layer shall adopt polymer cement waterproof mortar, waterproof mortar mixed with admixtures or admixtures.
4.2.3 The materials used for the cement mortar waterproof layer shall meet the following requirements.
1.Ordinary Portland cement, Portland cement or special cement should be used for cement, and cement that is expired or wetted and agglomerated should not be used;
2 The sand should be medium sand, the mud content should not be greater than 1.0%, and the sulfide and sulfate content should not be greater than 1.0%;
3 The water used for mixing cement mortar should be clean water without harmful substances;
4 The appearance of the polymer emulsion is a uniform liquid, without impurities, precipitation and stratification;
5 The technical performance of the admixture should meet the quality requirements of the current national or industry-related standards.
4.2.4 The base quality of the cement mortar waterproof layer shall meet the following requirements.
1 The surface of the base layer should be flat, solid, clean, and should be fully moist without clear water;
2 Holes and gaps on the surface of the base course should be blocked and smoothed with the same cement mortar as the waterproof layer;
3 Before construction, the embedded parts and wall pipes should be filled with sealing materials in the reserved grooves, and then the cement mortar waterproof layer should be constructed.
4.2.5 The construction of the cement mortar waterproof layer shall meet the following requirements.
1 The preparation of cement mortar should be accurately measured according to the technical requirements of the mixed materials;
2 Layered spreading or spraying, when spreading, it should be compacted and smoothed, and the surface of the last layer should be lifted and calendered;
3 The layers of the waterproof layer should be tightly bonded, and each layer should be constructed continuously; when it is necessary to leave a construction joint, a stepped slope should be used, but the distance from the male and female corners should not be less than.200mm;
4 After the cement mortar is finally set, it should be cured in time. The curing temperature should not be lower than 5°C, and the surface of the mortar should be kept moist. Washed by rain, after hardening, the maintenance method of alternating dry and wet should be adopted. In a humid environment, it can be maintained under natural conditions.
4.2.6 The number of sampling inspections for the sub-project inspection batch of cement mortar waterproof layer shall be 1 site per 100m2 of construction area, each site is 10m2, and shall not be less than 3 sites.
Ⅰ Master Control Item
4.2.7 The raw materials and mix ratio of waterproof mortar must meet the design requirements.
Inspection method. Check the product certificate, product performance test report, measurement measures and material entry inspection report.
4.2.8 The bonding strength and impermeability of waterproof mortar must meet the design requirements.
Inspection method. Check the mortar bond strength and impermeability inspection report.
4.2.9 The cement mortar waterproof layer and the base layer should be firmly combined without hollowing.
Inspection method. observe and lightly tap inspection with a small hammer.
Ⅱ General Items
4.2.10 The surface of the cement mortar waterproof layer should be dense and smooth, without cracks, sanding, pockmarks and other defects.
Inspection method. observation inspection.
4.2.11 The location of the construction joints of the cement mortar waterproof layer should be correct, and the joints should be operated in order of layers, and the layers should be tightly overlapped.
Inspection method. observe inspection and check acceptance records of concealed works.
4.2.12 The average thickness of the cement mortar waterproof layer shall meet the design requirements, and the minimum thickness shall not be less than 85% of the design thickness.
Inspection method. inspection by needle test.
4.2.13 The allowable deviation of the surface flatness of the cement mortar waterproof layer shall be 5mm.
Inspection method. check with a 2m gauge and a wedge-shaped feeler gauge.
4.3 Membrane waterproof layer
4.3.1 The membrane waterproof layer is suitable for underground projects affected by erosive media or vibration; the membrane waterproof layer should be laid on the water-facing surface of the main structure.
4.3.2 The membrane waterproofing layer shall adopt high polymer modified asphalt waterproof membrane and synthetic polymer waterproof membrane. The selected base treatment agent, adhesive, sealing material, etc. should match the roll material to be laid.
4.3.3 At the same time as the incoming material inspection, the seam bonding quality inspection of waterproof membranes shall be carried out in accordance with Appendix D of this specification.
4.3.4 Before laying the waterproof membrane, the base surface should be clean and dry, and the base treatment agent should be applied; when the base surface is wet, a moisture-curing adhesive or a wet interface release agent should be applied.
4.3.5 The yin and yang corners of the base should be made into circular arcs or 45° slope angles, and the size should be determined according to the type of coiled material; at the corners, deformation joints, construction joints, wall pipes and other parts, a coiled material reinforcement layer should be laid to strengthen Layer width should not be less than 500mm.
4.3.6 The overlapping width of the waterproof membrane shall meet the requirements in Table 4.3.6.When laying double-layered coils, the seams of the upper and lower layers and the adjacent two coils should be staggered by 1/3 to 1/2 of the width, and the two layers of coils should not be laid vertically to each other.
Table 4.3.6 Lap Width of Waterproof Membrane
4.3.7 Rolled materials laid by cold bonding method shall meet the following requirements.
1 The adhesive should be applied evenly, and should not be exposed or piled up;
2 According to the performance of the adhesive, the interval between the application of the adhesive and the laying of the coil should be controlled;
3 When paving, do not stretch the coiled material hard, remove the air under the coiled material, and roll it firmly;
4.The paving rolls should be flat and straight, and the overlapping dimensions should be accurate, without twisting or wrinkling;
5 The joints of the coiled materials should be fully glued with special adhesive or adhesive tape, and the joints should be sealed tightly with sealing materials, and the width should not be less than 10mm.
4.3.8 Hot-melt laying coils shall meet the following requirements.
1 The heating coil of the flame heater should be even, and the heating should not be insufficient or burn through the coil;
2 After the surface of the coil is melted, roll it immediately, remove the air under the coil, and stick it firmly;
3.The paving rolls should be flat and straight, and the overlapping dimensions should be accurate, without twisting or wrinkling;
4 The hot-melt modified asphalt rubber should overflow from the seam of the coiled material, and it should be pasted firmly and sealed tightly.
4.3.9 The self-adhesive method of laying coiled materials shall meet the following requirements.
1 When laying the membrane, the sticky side should face the main structure;
2 When paving the outer wall and roof, remove the air under the coil, and roll it firmly;
3.The paving rolls should be flat and straight, with accurate overlapping dimensions, without twisting, wrinkling and blistering;
4 After the façade coil is laid, the end of the coil should be fixed and sealed with sealing material;
5 During low-temperature construction, it is advisable to heat the coiled material and base surface with hot air, and then lay the coiled material.
4.3.10 The welded construction of coil joints shall comply with the following regulations.
1 Before welding, the coiled material should be laid flat, the size of the lap joint should be accurate, and the joint surface of the welding seam should be cleaned;
2 When welding, the lap seam of the long side should be welded first, and then the lap seam of the short side should be welded;
3 Control the temperature and time of hot air heating, and the welding place must not miss welding, skip welding or welding is not firm;
4 Do not damage the coils at the non-welding parts during welding.
4.3.11 Laying polyethylene polypropylene fiber composite waterproof membrane should meet the following requirements.
1 The supporting polymer cement waterproof bonding material should be used;
2.The full adhesion method should be used for the pasting of the coiled material and the base layer, and the bonding area should not be less than 90%.
3 The thickness of the cured adhesive should not be less than 1.3mm;
4 Adhesive material should be extruded from the seam of the coiled material, and the edge of the joint surface should be coated with polymer cement adhesive material with a thickness of 1.3mm and a width of 50mm;
5 Before the polymer cement binder solidifies, it is not allowed to walk on it or carry out subsequent operations.
4.3.12 The polymer self-adhesive film waterproof membrane should be constructed by pre-laying anti-adhesive method, and should meet the following requirements.
1 The coiled material should be laid in a single layer.
2 When laying on a wet base surface, the base surface should be flat and firm without clear water;
3 The long side of the coil should be lapped with self-adhesive side, the short side should be lapped with adhesive tape, and the lapped areas at the ends of the coil should be staggered;
4 During facade construction, within 10mm to 20mm from the self-adhesive edge to the edge of the coiled material, mechanical fixation shall be carried out every 400mm to 600mm, and the fixed position shall be completely covered by the coiled material;
5 The waterproof layer shall not be damaged when pouring structural concrete.
4.3.13 After the waterproof layer of the membrane is completed and passed the acceptance, the protective layer should be made in time. The protective layer shall meet the following requirements.
1 An isolation layer should be set between the fine stone concrete protective layer and the waterproof layer of the top slab. Fine stone concrete protection...
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