Construction Science Polyurethane Rigid Foam Spraying Exterior and External Insulation Construction Wang Cuiying Song Wei Wang Liyan (China Coal Construction Group Corporation) urethane hard foam spraying for main insulation, taking rubber powder polystyrene granule insulation slurry leveling and supplementary insulation, making full use of polyurethane excellent The thermal insulation and waterproof performance as well as the flexible anti-cracking performance of the rubber powder granule external thermal insulation system are external thermal insulation systems with advanced technology and excellent thermal insulation performance.
1 Polyurethane Brewing Hard Foam Spraying External Thermal Insulation Technology System Constructs 6 units of the second phase of the C District of Liuliqiao Xincun Residential Quarter, 2 underground joint garages with a total construction area of ​​114,805 square meters. According to the design requirements, the external wall insulation must be To achieve the 65% energy saving requirement, the insulation layer of 7 unit projects in the group project is selected from the 53M method of the outer wall in the general map of the North China Building Structure (882 -9), namely the rigid foam polyurethane + composite rubber powder polystyrene particles. The wall is covered with exterior bricks.
According to the practice of the outer wall 53M in the general drawing of the North China Building Structure (882-9), when the thickness of the polystyrene particles of the rubber powder is 20 mm, the thickness of the rigid foamed polyurethane must be 50 mm thick, and the heat transfer coefficient is 0.43. W/mK meets the requirements of energy saving 657. The structural design of the rigid-bubble polyurethane + composite rubber powder polystyrene granule exterior insulation system in the 7 units of the second phase of Liuliqiao Xincun residential district is as follows: 2 External wall external thermal insulation construction process 2.1 Basic treatment of external wall insulation before construction The vertical line of the large wall should be hoisted first. If the vertical deviation of the wall is greater than lcm, 1:3 cement mortar should be applied for leveling. In addition, the residual ash on the wall must be cleaned up.
2.2 Brushing Polyurethane Moisture-Proof Primer Use a roller brush to evenly coat the polyurethane moisture-proof primer without leakage. The thickness of the moisture-proof primer is about 15/am. 2.3 Preparation of insulation layer before construction Large-area spraying of external wall insulation must be carried out to control the thickness and verticality of the insulation layer; (2) For wall width greater than 2 meters, additional horizontal control line is required. Before the polyurethane is sprayed, the non-coating materials such as doors and windows, scaffolding, etc. are shielded and protected by plastic film. 2.4 Insulation layer construction should be completed in multiple times, and the thickness of each spray coating should be controlled. The thickness of the final polyurethane insulation layer is 50mm. Yang angle ruler partial occlusion of an aluminum alloy directly sprayed to make a right angle.
When the polyurethane spray reaches 10mm thick, the thickness rod is inserted according to the plum blossom distribution at a pitch of 500mm. The density should be controlled at 4-5/m2, and then the solvent-free rigid foam polyurethane is continuously sprayed until the benchmark head is covered by the material.
After 20 minutes incubation with Coating cutter, standard, transition occurs, the occurrence of microcracking. There are two cases causes the temperature is too sling: First, the upper limit of asphalt factory temperature exceeds the specification; the second is asphalt factory, although the temperature within the specified range, but close to the limit of the sling, if shorter transport distance The paving and rolling is very timely, which will make the rolling temperature exceed the specification high limit.
The basic level, sub-base, the road surface clean.
Before a structure layer on the paving, pavement layer and the surface dust shall subgrade surface, floating dust, floating sand cleaned, or to rain effect, soft blanket fines is caused by driving the high-pressure extrusion into water erosion The slurry, which in turn spreads to the surface of the asphalt surface.
Strictly control the base layer loosening factor (or base layer standard).
The secondary supplementary layer will be caused by lax control. The secondary supplementary layer and the lower base layer cannot be closely connected, and the thickness of the secondary layer is small, so it is easy to loose, which causes the asphalt layer to be cracked, loose, and pitted. If it is necessary to supplement it twice, it is recommended to replace the additional layer with an oily asphalt mixture. - Ensure that the base S realism meets the design criteria. In the case where the maximum dry density is determined, the degree of compaction of the base layer is closely related to the ratio of the coarse and fine aggregates in the mixture, especially the content of the coarse aggregate. When the coarse content is large, even if the compaction exceeds 100% Does not mean that the base layer has been compacted. Therefore, it is necessary to appropriately increase the rolling tonnage, increase the number of rolling passes, ensure the base layer to the specified compaction density, and avoid the defects such as surface pits and local subsidence.
2.3 The main purpose of the scientific aspects of road maintenance is conservation, and keep in good condition and road facilities, timely repair damaged parts. Provide users with a safe, comfortable and smooth driving road under various climatic conditions. Taking correct technical measures, extending the life of the road, and maintaining the landscape and environment around the road are also a goal of road maintenance.
Reasonable choice of maintenance countermeasures. On the one hand, we must consider the current situation of the road, that is, the performance indicators of each use meet the requirements of use. The corresponding countermeasures should be selected according to the aspect and degree of incompatibility. On the other hand, we must consider the need for road maintenance and reconstruction in the future. According to the state of social and economic development, it is necessary to adopt measures to improve the degree of improvement in areas with rapid socio-economic development and large traffic volume. Of course, economic benefits and acceptability should be considered in this process.
The establishment of maintenance countermeasures should be selected for the main diseases appearing on the road surface so as to be targeted.
3 Conclusions Dry road damage has become one of the main hazards of asphalt pavement. Traffic management departments at all levels should pay enough attention and take a series of prevention according to their causes from pavement design, raw material approach to specific construction. And improvement measures. At the same time, it is necessary to establish a sound quality assurance system, from the management department, the design department to the construction department, paying attention to it at different levels, layer-by-layer control, and implementation at all levels. Only in this way can we fundamentally reduce the occurrence of drought damage on the asphalt pavement and improve the quality of urban road construction to a new level.
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