For the composite layer of precast girder, one measuring hole shall be set for each beam; j.
For the slab wall of shear wall structure, one formwork shall be measured for each axis of the transverse wall, and the quincunx layout shall be adopted between the longitudinal strength axes.
5.2 according to the layout of temperature measuring points, the temperature measuring hole can be made of embedded metal casing with inner diameter of 12mm, and the hole shall be watched by a specially assigned person, To prevent construction from stepping on (pressure) measure the temperature hole and number the temperature hole.
When the ambient temperature is lower than -Welding shall not be carried out at 20 ℃.
5.4 concrete poured in winter, The freezing critical strength shall comply with the following provisions: (1) ordinary concrete shall be configured with Portland cement or ordinary portland cement, which shall be 30% of the designed standard value of concrete strength, and the concrete prepared with slag Portland cement shall be 40% of the designed standard value of concrete strength, but when the concrete strength grade is C10 and below, it shall not be less than 5.0n/mm ²， When the construction needs to improve the concrete strength grade, it shall be determined according to the improved strength grade; (2) The concrete mixed with antifreeze shall not be less than 4.0n/mm when the outdoor minimum temperature is not lower than – 15 ℃ ², When the outdoor minimum temperature is not lower than – 30 ℃, it shall not be less than 5.0n/mm ²。 5.5 thermal calculation of concrete shall be carried out for concrete construction in winter.
(3) The thermal insulation layer outside the formwork and covered on the concrete surface shall not use wet materials, nor shall the thermal insulation materials be directly covered on the wet concrete surface.
Two measuring holes shall be set for each reinforced independent column foundation, one measuring hole shall be set for strip foundation every 5m long, and one measuring hole shall be set for box foundation bottom plate every 20m2.
03 General requirements for deepening the reform of government procurement system (1) atmospheric indoor and outdoor temperature measurement records; concrete mold temperature, tank temperature and slump inspection records.
The distance between the upper and lower measuring holes is large, and the upper and lower edges of the formwork are 30-50cm; h.
When the heating temperature exceeds 45 ℃, the temperature stress shall be calculated..
the temperature measuring holes of cast-in-situ concrete beams, plates and ring beams shall be left perpendicular to the horizontal direction of beams and plates; C.
For cast-in-situ reinforced concrete structural columns, a temperature measuring hole is set at the upper and lower joints of each column, forming an inclination angle of 30 degrees with the column surface; f.
the temperature measuring holes are generally arranged at the parts with large temperature change, easy to dissipate heat and easy to freeze components; B.
(4) the mix proportion of concrete and mortar and the measurement of mixing.
The cement grade shall not be less than 32.5, and the minimum cement consumption shall not be less than 300kg / m ², The water cement ratio shall not be greater than 0.6.
(2) The aggregate used for mixing concrete shall be clean and shall not contain ice, snow, frozen block and other easily understandable materials, and then mixed with antifreeze containing potassium and sodium ions.
(2) Requirements for setting temperature measuring holes in various buildings a.
(2) the mobilization acceptance of winter materials and the storage of the other party.
Cast in situ balcony cantilever beam, rain cover, outdoor stair rest platform and other sporadic components, each with 2 temperature measuring holes; k.
(1) Portland cement and ordinary portland cement shall be preferred for concrete construction in winter.
5.3 flash butt welding, arc welding and pneumatic welding should be used for steel reinforcement and negative temperature welding.
prefabricated frame The column head shall be poured first, one measuring hole shall be set at the upper end joint of each column, and a pair of measuring holes shall be set at the lower end joint of each column; Inclined at an angle of 30 degrees to the cylinder; e.
(5) Implementation of test block maintenance and witness sampling for maintenance.02 winter construction scheme inspection formulate targeted winter construction scheme according to the project characteristics to clarify the parts of winter construction; preparation of materials and quantities required for winter construction; methods and technical schemes selected for winter construction; arrangement of temperature measurement personnel for winter construction; safety technical measures for winter construction (fire prevention, gas prevention, poisoning prevention, etc.).
(2) temperature measurement records of concrete and mortar, layout of temperature measurement points; concrete maintenance records; retention and temperature measurement records of test blocks under the same conditions.
A layer of plastic film shall be paved on the surface of newly poured concrete.
The main inspection contents of winter construction are (1) the construction of winter construction management system and the work license of special operators of the construction unit.
(3) the preparation, review and implementation of winter construction scheme.
Active aggregate or materials mixed with such materials shall not be used in concrete.
(4) If the overall structure is heated for curing, measures that can prevent large temperature stress shall be taken for the setting of pouring procedure and construction joint position.
The end time of temperature measurement: the concrete reaches the critical strength, the surface temperature of the concrete and the ambient temperature difference after formwork removal are < = 15 ℃, the cooling rate of the concrete does not exceed 5 ℃ / h, and the temperature of the temperature hole is close to the atmospheric temperature.
For thick bottom plate, one or two layers of temperature control points shall be added in the middle and lower part of the bottom plate to master the internal temperature of concrete.
A pair of temperature measuring holes shall be set at the column head and column base of cast-in-situ concrete columns, and the pre column surface shall be inclined at an angle of 30 degrees; D.
(3) Concrete mix proportion, certificate of conformity, alkali content and admixture selection and re inspection report.04 on site physical inspection: (1) material preparation for on-site winter construction; (2) whether on-site winter construction is consistent with the winter construction scheme; (3) concrete maintenance and temperature measurement; (4) Winter construction and thermal insulation of on-site reinforcement welding, temperature rise of warm shed of mixer, temperature rise of water, sand and stone; (5) mixing of on-site cement mortar and concrete, inspection of outlet temperature, molding temperature and slump of commercial concrete; (6) Winter construction control of on-site masonry works, waterproof works, backfill works, steel structure works and decoration works.05 reinforced concrete works 5.1 setting of temperature measuring holes (1) the layout and depth of temperature measuring holes shall be prepared in plan and elevation, and each hole shall be numbered in sequence and implemented after being approved by the technical department.
Three temperature measuring holes shall be set on one side of each slab, which shall be arranged diagonally.
For the slab wall of cast-in-situ frame structure, one measuring hole shall be set every 15m, and at least one hole shall be set for each wall; g.
