With the increase in high-rise buildings, both commercial and residential buildings, office buildings, large shopping malls, public **** building, etc., there is generally a larger area of the basement such as: parking lots, manned defense requirements and equipment rooms. And groundwater leakage of this common disease has been plagued by us, affecting the structure and use of function. I participate in the construction of Qingyang People's Hospital comprehensive inpatient building project, the basement is mainly medical equipment rooms, such as: fluoroscopy room, film room, lithotripsy room, CR room, ultrasound room, etc., which has high requirements for the basement leakage prevention project. According to the relevant norms, standards and my work and learning experience, summed up the following prevention and control measures and insights.
1, gray soil bedding construction quality control
In fact, gray soil bedding also has a very good anti-seepage effect on groundwater, so do a good job of gray soil bedding construction is necessary. I participate in the construction of Qingyang People's Hospital comprehensive inpatient building project, gray soil bedding design for the thickness of 500mm, 3︰7 gray soil ratio, compaction coefficient of 0.97. Construction requirements of gray soil particle size and impurity content in line with the specification requirements, the gray soil mixing uniformity, moisture content in line with the requirements of the layers of tamping, compaction coefficient of compliance with the design requirements, smooth and no cracks.
2, bedding, foundation slab, basement sidewall waterproofing layer construction quality control
The concrete bedding layer requires flat without cracks, so as to ensure the quality of construction of waterproofing layer, Qingyang People's Hospital Comprehensive Hospitalization Project, designed for the basement floor (outside the outside of the posting of the defense) 100-thick C15 concrete bedding, 20-thick 1︰2.5 cement mortar leveling layer, 2-thick non-tar polyurethane waterproofing 50 thick C20 fine stone concrete protection layer. Basement side wall (external defense external paste) 20 thick 1︰2.5 cement mortar leveling layer, 2 thick non-tar polyurethane waterproofing coating. 20 thick 1︰2.5 cement mortar protection layer, 120 thick standard brick protection wall, M5 cement mortar masonry, 3︰7 gray soil backfill. First of all, to ensure that the material performance, quality in line with the design and standards, and product certification, test reports. Waterproof layer and its deformation joints, buried fittings, detailing practices, must comply with the design requirements and construction and acceptance specifications. Waterproof layer of the grass-roots level should be firm, clean surface, dense and flat, yin and Yang angle arc, the primer coating should be uniform, no leakage coating. Additional layer of painting method, lap, head should be in accordance with the design requirements, bonding must be firm, joints closed tight, no damage, hollow drums and other defects. Coated waterproofing layer, coating thickness uniformity, bonding firm and tight, not allowed to have peeling, cracking, eyelets, painting crimping defects, fine stone concrete protective layer and cement mortar protective layer shall not be empty drums, cracks, shedding of phenomena. 3︰7 gray backfill must meet the requirements of the design and specifications.
3, water concrete construction quality control measures
Basement waterproofing concrete structure construction quality is the key part of the basement waterproofing quality control. Qingyang people's hospital comprehensive inpatient building project, designed for the foundation slab strength grade C35, impermeability grade S6, basement wall strength grade C40, impermeability grade S6. Basement waterproofing concrete is very easy to produce cracks in construction, which is mainly a problem of concrete shrinkage. Concrete in the hardening process to contraction and deformation, deformation is constrained and cause strength contraction of tensile stress, when the tensile stress exceeds the cracking strength, causing cracks. Therefore to prevent leakage, the key to control the cracks.
A, set expansion joints, pouring belt, expansion strengthening belt is a common method to effectively control the concrete structure cracks. Qingyang People's Hospital Comprehensive Inpatient Building Project adopts the continuous pouring method of expansion reinforcement belt, that is, pouring reinforcement belt in the place of large shrinkage stress, so that it produces large expansion to compensate for the shrinkage of concrete.
B, concrete mixed with additives or external admixtures. The concrete is mixed with expansion agent to compensate for the shrinkage stress of concrete. Or in the concrete mixed with fiber (steel fiber, polypropylene fiber, etc.) class, the fiber has a certain anti-strength, and concrete grip in the concrete was distributed in all directions, to enhance the tensile stress in the process of hardening of concrete, to control the emergence of concrete cracks.
C, set the anti-cracking steel bars. Increase structural reinforcement, improve crack resistance, horizontal reinforcement in the basement wall should try to use a small diameter, small spacing, so that the structural reinforcement to achieve the role of the temperature tendon, can effectively improve the anti-cracking properties. The above anti-cracking measures have been considered in the Qingyang People's Hospital Comprehensive Inpatient Building Project.
D, do a good job of concrete ratio and maintenance work
① low heat of hydration, urinary power of cement; ② use clean sand, strictly control the mud content of sand shall not be more than 3%; ③ stone using pebbles or crushed stone with a continuous grain; ④ the use of admixtures and admixtures, to improve the ease of concrete mix, reduce the water-cement ratio, reduce the amount of water, to prevent the excess water in the concrete caused by cracks and voids. and voids. External admixtures can replace part of the cement, reduce the heat of hydration, and reduce the temperature cracks and shrinkage cracks in concrete; ⑤ The degree of collapse should be selected according to different parts of the basement and construction technology; ⑥ The amount of cement, admixtures and external admixtures. According to the requirements of the site, the trial allocation, water-cement ratio should be controlled below 0.55; ⑦ ratio and sand rate should be selected by the laboratory, to optimize a variety of parameters, and test mix the workability of the concrete, the production of specimens to test the strength and seepage resistance of the standard; ⑧ after the concrete is poured, it must be covered with heat preservation and maintenance in 12h, and after that the surface of the concrete should be kept in moisture maintenance to 14d. In order to prevent the emergence of dry shrinkage cracks and temperature cracks, its surface Measures should be taken for heat preservation and moist maintenance. Qingyang People's Hospital comprehensive inpatient building foundation base plate thickness 600, local thickness 1200 is large volume concrete, for large volume concrete should take effective temperature control measures, make temperature measurement records, control the temperature difference between inside and outside ≤ 25 ℃; ⑨ winter construction, water and sand should be heated according to the provisions of the winter program to ensure that the concrete into the mold temperature is not less than 5 ℃, the use of integrated heat storage method of heat preservation and maintenance, winter construction of antifreeze mixed with the antifreeze agent should be selected Use certified products. Demolding concrete surface temperature and ambient temperature difference of not more than 15 ℃.
E, template construction process control
The template should be firm, tight joints, no slurry leakage. Template deformation or slurry leakage, very easy to cause water leakage. The template should be stipulated to weld the water-stopping ring on the tensile bolts.
F, concrete construction process control
①Concrete pouring. In order to avoid concrete layering, segregation, pouring should be strictly control the free fall of the mixture. Pouring can be carried out in layers and segments, but it should be noted that the interval between layers and layers, segments and segments of the pouring time shall not exceed the initial setting time, so as to avoid the emergence of construction joints and lead to leakage.
②Improve the amount of concrete vibration group. Basement concrete should be comprehensive and detailed vibration, material and vibration to form a certain order, to prevent leakage, under vibration. To be in the lower layer of concrete before the initial set on the lower layer of concrete material, tamping vibrator straight into the lower layer of concrete 5-10cm, to ensure the quality of the concrete in the joint parts. To strictly control the vibration time, to the concrete began to grout and bubbles prevail, shall not be under vibration or over vibration.
G, the treatment of construction joints
This includes the treatment of construction joints on the exterior wall of the basement and the construction joints of the back pouring zone. The outer wall construction joints should be located in the outer wall 30cm above the baseboard. For the basement to leave the construction joints, should be set up to stop the water steel plate, rubber water stop or leave according to the design requirements. Before catching and pouring concrete, the floating slurry on the surface of the original concrete should be chiseled away and carefully cleaned before pouring new concrete. The concrete of the back pouring zone should be used with expansion agent concrete to compensate for the shrinkage of concrete.
H, the treatment of embedded parts
Pre-embedded parts penetrating through the outer wall should be welded on each pre-embedded parts to stop the water ring. Pre-embedded parts penetrating the template should be blocked tightly, no slurry leakage. When the concrete is poured, attention should be paid to the concrete under the pre-embedded parts should be well vibrated to prevent the emergence of voids and honeycomb.
4, the quality of work should pay attention to:
① Strictly control the water-cement ratio, do not arbitrarily add water in the concrete, water-cement ratio is too large will affect the expansion rate of compensation shrinkage concrete, directly affect the effect of compensation shrinkage and reduce shrinkage cracks.
① Detailed structural treatment is the weak link of waterproofing, pre-construction should review the drawings, special parts such as deformation joints, construction joints, through the wall pipe, buried parts and other details to be carefully handled.
③ basement waterproofing project must be waterproofing professional team construction, its technical director and team leader must hold a certificate of competence. Construction is complete, timely collation of construction technical information, hand over to the general contractor archives. Basement waterproofing project warranty period of three years, leakage to be responsible for repair.
4 through the wall pipe with a water stop ring casing, should be pre-buried before pouring concrete fixed, water stop ring around the concrete to be carefully vibrated and compact, to prevent leakage of vibration, the main pipe and casing according to the design requirements of waterproofing sealing paste sealing tightly.
5 structural deformation joints should be handled in strict accordance with the design requirements, the position of the waterstop should be fixed accurately, the concrete around the careful pouring and vibration to ensure that the dense, the waterstop shall not be shifted, deformation joints filled with asphalt wood fiber board or polyethylene foam stick, the seam filled with waterproofing sealing paste at 20mm, in the surface of the water surface with a waterproofing membrane, and wiped 20mm of waterproofing mortar protection.
6 after pouring joints generally to be six weeks after the concrete is poured, should be the original design of the concrete grade increased by one level of U.E.A compensatory shrinkage concrete pouring, pouring before the hewing should be cleaned up, maintenance of 28d.
5, protection
① in the construction of the finished product should be protected from touching waterproofing, construction joints, pengkou and water stops.
② Protect the wall pipe, electrical conduit, electrical door boxes and buried parts, etc., do not squeeze the vibration bias or buried parts into the concrete.
More about the engineering/service/procurement category of the tender writing production, enhance the winning rate, you can click on the bottom of the official website customer service free advice:/#/?source=bdzd