1. Several commonly used waterproofing materials
Waterproofing material is the material basis of waterproofing engineering and the main barrier to prevent rainwater intrusion and groundwater infiltration of buildings and structures. The quality of waterproofing material has a great impact on waterproofing engineering. Therefore, waterproofing material must be studied from the perspective of waterproofing material.
1.1 Rigid waterproof material waterproof concrete waterproof concrete has both structural layer and waterproof layer. Its waterproofing mechanism relies on the compactness of structural components (such as beams, slabs, walls, etc.) concrete itself, together with some structural measures (such as setting slope, water stop ring, etc.) to achieve the purpose of self-waterproofing of the structure. The construction preparation of this material is as follows:
1.1.1 Operating conditions. (1) Complete the receipt and acceptance of the concealed inspection and pre-inspection of reinforcing bars and formwork, and check whether the wall bolts, equipment pipes, construction joints and embedded parts in waterproof concrete structures have been waterproofed in the concealed inspection and pre-inspection; 2) Prepare the construction plan in advance; 3) The mix proportion has been determined by test.
1.1.2 Material requirements. (1) Cement: Portland cement of grade 32.5 or ordinary Portland cement can also be used as slag Portland cement; (2) Sand: medium sand should be used, mud content should not be greater than 3%, mud content should not be greater than 1.0%; (3) Stone: pebble should be used, the maximum particle size should be 5-40 mm, mud content should not be greater than 1.0%, mud content should not be too large; (4) Admixture: its content should be confirmed by experiment. Certainly, the grade meets the standard requirements.
1.2 Coil waterproofing material asphalt waterproofing membrane asphalt waterproofing membrane is a sheet waterproofing material which can be curled by base paper, fibre fabric and other matrix materials infiltrating asphalt and spreading powder, granular powder or sheet material on the surface. Petroleum asphalt paper tyre is a traditional waterproof material in our country, which still occupies the main position in roofing engineering at present. It has the characteristics of good flexibility at low temperature, short service life of waterproof layer and low price. In the construction of underground waterproofing layer, when the groundwater level is high, the groundwater level should be lowered before the waterproofing layer is laid. The groundwater level should be 30 cm below the waterproofing layer bottom elevation and be maintained until the waterproofing layer is completed. The surface of the base layer with waterproofing layer should be cleaned up of dust and debris, and the remaining hard blocks and prominent parts of the surface should be cleaned up, and no hollowing, cracking, sand-lifting and peeling should be allowed. Phenomenon: The coil used in waterproof layer, basic treatment agent and inflammable articles should be stored separately, away from fire source, and do a good job of fire prevention.
The material requirements of coil waterproof material must conform to the specifications, must have the quality certificate of the factory, and have the inspection report issued by the relevant qualification grade inspection department. The waterproof layer of coil is hollow, which occurs between the leveling layer and the coil, and mostly at the joint of the coil. The reason is that the leveling layer is not dry, sweat rate is high, air is not thoroughly removed, and the coil is not firmly bonded. Leakage mostly occurs at the root of the pipe, ground leakage, deformation joints, etc. The expansion joints are not broken, resulting in the tearing of the waterproof layer, and other parts may also leak due to the weak bonding. Inspection should be strengthened in construction and careful operation should be carried out.
1.3 Polymer synthetic material coating waterproofing material Synthetic polymer waterproofing material is a one-component or multi-component waterproofing coating made up of synthetic rubber or synthetic resin as the main film-forming material and other auxiliary materials. Compared with the commonly used materials, it seems relatively new.
Waterproof coating is a kind of polymer synthetic material which presents viscous liquid at room temperature. After coating on the surface of the base layer, a tough waterproof film is formed by volatilization of solvent or evaporation of water or chemical reaction between components, which plays the role of waterproof and moisture-proof. The waterproof coating has the characteristics of complete waterproof layer, no joint, light weight, simple and convenient construction, easy repair and long service life. If the waterproof coating is used with sealant filling material, it can enhance waterproof performance, effectively prevent leakage, and prolong the durability of waterproof layer.
1.3.1 Material requirements Because of the large amount of organic solvents in two-component and multi-component polyurethane waterproofing coatings, which cause serious environmental pollution and are prohibited in some aspects, the use of one-component polyurethane waterproofing coatings, which are made of polyether as the main raw material and various additives, belongs to one-component flexible coatings without volatilization of organic solvents, and its solid content is low in strength. The high elongation is more than 80% and the tensile strength is more than 1.9%.
1.3.2 During the operation of the protective coating waterproof layer of finished materials, the operators should wear flat shoes. During waterproofing construction with coatings, the walls and floors of other parts shall not be polluted. After the construction of the coated waterproofing layer, it should be strictly protected. No one can enter it or pile up sundries on it to avoid damaging the waterproofing layer. When the waterproof protective layer is constructed, mortar shall not be mixed on the waterproof layer, iron bars shall not touch the waterproof layer when laying mortar, and the waterproof layer shall not be damaged by meticulous work.
2. Application of Roof Waterproof Technology
2.1 The setting and practice of partition joints should be set at the supporting end of the roof, at the corner of the roof, at the junction of the waterproof layer and the prominent roof, and should be aligned with the roof joints so as to concentrate the cracks in the waterproof layer caused by the temperature difference and the deformation of the concrete shrinkage structure on the partition joints so as to avoid the cracks in the slab surface. The spacing of the lattice joints should not be too large. When the spacing is greater than 6 m, a "v" shaped lattice joint should be set in the middle, and the depth of the lattice joint should run through the thickness of the waterproof layer. When the lattice joints are used as exhaust ports, the joints can be widened appropriately and the exhaust vents can be set up. When the roof uses petroleum, asphalt and felt as waterproof layer, the lattice joints should be covered with 200 mm to 300 mm wide linoleum, and the lattice joints should be single-sided with asphalt glue and filled with ointment.
2.2 The method of roof leveling is the combination of building slope finding and structural slope finding. First find the slope according to 3% structure, then use 1:6 cement slag or cement expansive concrete stone to find the slope on the structure layer, and then make a 25 mm thick 1:2.5 cement mortar leveling layer. When building find the slope, we must find the flooding gradient, the flow direction, straighten the highest point and the outlet with fishline, hit the point, hit the bar, the thickness of the outlet must not be less than 30 mm. When pouring, we must use roller and ruler to roll. Make it dense by pressing.
2.3 The method of roof isolation layer is adapted to local conditions in construction, and the waterproof layer of two-cloth and three-oil rolled material on the surface is made between the leveling layer and the rigid layer, which not only plays the role of isolation layer, but also is not exposed to sunlight and rain, thus preventing the ageing of ointment, but also plays a waterproof role.
In the construction of coil waterproofing layer, the following points should be paid attention to: 1) scraping the base treatment agent on the base, requiring thin and uniform, generally after drying, the coil can be laid without sticking hands; 2) the coil waterproofing layer should be laid by the lowest elevation of the layer up parallel to the roof, so that the coil can be lapped in the direction of water flow, and when the slope of the roof is greater than 10%, the coil should be vertical to the roof ridge. Laying method: stripping the isolation paper on the ridge of the coil, sticking the coil to the base surface, keeping the long side overlap 50 mm, the short side overlap 70 mm, the coil requires to maintain the state of natural relaxation, do not pull too tight, after the coil is laid, it should be fully compacted with a plane vibrator immediately, and the vertical part should be hammered with a rubber hammer; (4) Coil overlap bonding: after the coil is compacted, the coil should be fully compacted. Open the overlap part and apply the overlap adhesive evenly with a paint brush. When the two bonding surfaces of the coil joint are opened and dry for a short time without sticking, the overlap can be bonded. Then the rubber hammer is used to knock compactly so as to avoid leakage caused by cracking. _The construction temperature of the waterproof layer should be above 5 C.
Waterproof engineering is a key project and concealed project in construction, which plays an important role in ensuring the quality of the project. Although the waterproofing measures used at present have been greatly improved, they are far from enough to meet the requirements of Engineering development. In the new century, the quality requirements of the project are getting higher and higher. We should pay more attention to the development of new materials to meet the development requirements of waterproofing projects and build high-quality and high-level projects, so as to repay the society and serve the society.