Introduction to the construction process of pulp masonry in water conservancy engineering
Pulp masonry construction steps:
(1) The masonry body should be built by extrusion method, the consistency of mortar should not be less than 50mm, and when the temperature changes, it should be appropriately adjusted.
(2) The corners and junctions of the masonry body built by the pulp masonry method should be masonry at the same time, and the surfaces that cannot be masonry at the same time must be left at the time break, and should be masonry into a diagonal maple.
(3) The permissible deviation of the size and position of the masonry body shall not exceed the relevant provisions of Table 7.3.1 of gb50203-2002 of the "Code for The Acceptance of the Construction Quality of Masonry Engineering".
material:
1) The block should be clean and free of frost attachment; the sand must not contain ice cubes or frozen clumps. Blocks that are frozen after soaking in water cannot be used.
2) The masonry mortar of construction must be maintained at a positive temperature, and the temperature difference between the mortar and the surface of the stone should not exceed 20 ° C.
3) Masonry masonry, mortar should be mixed with ordinary Portland cement, mortar should be mixed with mixing, mixing time should be increased by 0.5 to 1 times compared with room temperature, and the consistency of masonry mortar is required to be 40 to 60mm.
When the temperature suddenly drops, the following measures should be taken for the masonry works under construction:
1) The material of mixing mortar is heated, the water temperature shall not exceed 80 ° C, and the sand shall not exceed 40 ° C, so that the mortar temperature shall not be less than 20 ° C
2) The speed of mixing mortar is closely coordinated with the progress of masonry, and it is mixed and used as needed
3) The finished part is covered with insulation materials, the temperature is lower than 5 °C, and it cannot be sprinkled for maintenance.
In order to accelerate the hardening of the mortar and shorten the holding time, early strength agents such as calcium chloride can be added to the cement mortar, and the dosage is determined by test. When the temperature is below 5 °C, water cannot be sprinkled for maintenance.
Progress of construction projects
Pulp masonry construction is made of extruded layered masonry. Masonry should first lay a layer of thick mortar 3 to 125px thick on the foundation surface, and then place stones with the large side facing down. The masonry procedure is to first build "corner stones", then "face stones", and finally "belly stones". (1) Corner stone to determine the position and beginning of the building, in the selection of stone and masonry must be doubled attention, to choose a more square stone block, first test, if necessary, a little chisel, and then paved ash masonry, the corner stone of the position of the masonry method must be accurate, after the corner stone masonry, you can hang the sample line to the corner stone. Face stones can vary in length
(2) The exposed surface of the face stone should be relatively flat, the thickness should be slightly the same as the angle stone, the same level should be roughly flat, and the height difference of adjacent masonry blocks should be less than 2 to 75px. Masonry surface stones should also be tested and chiseled first, and then the mortar is laid, the stone is turned back into the seat masonry, and the extrusion method is used to construct and squeeze the mortar tightly. The ascenter can be filled in layers with smaller stones, with a seat slurry laid before filling. When filling the first layer of abdominal stone, it must be placed in a large direction downwards, try to minimize the gap between the stone seams, and then fill the gap with mortar 1/3 to 1/2, and put in the appropriate stone blocks, gently tapping with a hammer, so that the stones are squeezed into the ash seam, and the construction method of filling mortar or dry filling stone blocks must not be placed first, and the stones must not be in contact with each other, and the seat pulp and vertical seam mortar filling should be full and dense, and the slurry should be evenly laid.
(3) When masonry, the stones should be laid in layers, and each layer height should be leveled once. It requires flatness, stability, compactness, staggered seams, and overlapping inside and outside.
(4) The masonry height of the masonry should not exceed 1.2m per day, and when the masonry process is temporarily interrupted for any reason, a stepped inclined chakra should be left, and its height should not exceed 1.0m, and the construction should continue when the mortar strength reaches 25kg/cm2 or more.
(5) Before continuing masonry, the scum on the surface of the original masonry should be removed and then brushed clean, and the vibration of the lower masonry should be avoided during masonry.
Grout: The grout should be carried out after 24h of the construction of the slurry masonry, the width of the seam is not less than the width of the seam, the depth of the seam is not less than 2 times the width of the seam, the groove seam must be rinsed clean before the seam, no ash residue and water must be left, and the seam surface should be kept moist.
The grout must be mixed separately, it is strictly forbidden to mix with masonry mortar, the grout mortar with a higher label M10 for caulking, requiring the grout mortar to use fine sand and a smaller water-to-ash ratio, and its ash-to-sand ratio is controlled between 1:1 and 1:2. The grout should maintain the natural joints of the block masonry.
When the hook is completed and the mortar is initially condensed, the surface of the masonry should be brushed clean, at least covered with wetting for 21 days, and water should be sprinkled frequently during maintenance to keep the masonry moist and avoid collisions and vibrations.
Pulp masonry maintenance: masonry exposed surface, between 12 and 18h of masonry should be maintained in time, often keep the exposed surface moist, need to be covered with sacks or straw bags, and often sprinkle water maintenance to keep the surface moist. The maintenance time is generally not less than 14 days, and the water is no longer sprinkled during the winter, but the sack is covered with insulation. Before the masonry has reached the required strength, it is not allowed to arbitrarily stack heavy objects or chisel stones on it, so as to avoid vibration damage to the masonry.
Precautions: 1, according to the design requirements of the slurry masonry along the direction of the dam body joint (settlement joint) spacing of 15m, the width of the joint 20mm, embedded low foam polyethylene board.
2. According to the design requirements, the slurry masonry protection is flat seam.
3. The grout mortar must be mixed separately, and it is strictly forbidden to mix with masonry mortar.