The characteristics of the performance for EPS external thermal insulation material
At present, with the boom of construction energy conservation, heat preservation system of all kinds of popularization and application of material on the market.In the insulation system material, polystyrene board thin plastering exterior wall thermal insulation system (EPS) because of its good thermal insulation effect, high cost performance and strong adaptability, advantage and dominant.EPS external wall insulation system is composed of EPS board, bonding mortar, the mortar, alkali resistant glass fiber grid cloth material composition and so on, all kinds of materials have different role in the system.
EPS board is composed of a closed of particle, suborbicular, each particle's diameter of 0.2 mm to 0.5 mm, particle wall thickness from 0.001 mm to 0.001 mm. Polystyrene was 2% ~ 2%, and the rest to the air. According to the requirement of the national industry standard JG149-2003, the apparent density of EPS board in 18 ~ 22 kg/m3, the coefficient of thermal conductivity should be less than 0.041 w/(m · Kelvin).In addition, the EPS board should be under the condition of natural aging before they go out in 42 days or 60 degrees Celsius in the steam age 5 days. Time enough, if Chen EPS board in use process, may produce certain contraction deformation or warp, make the system part of the stress concentration and finally result in the crack of the system, empty drum.
Cement as a kind of dry mortar, plays an important role in the EPS system, it is an important hub connects insulation board and wall at the grass-roots level. Because the primary wall easy bibulous, so in the cement mixed with cellulose ether can have good water, thickening and improvement the action such as construction. Good water retention can ensure the slurry will not due to lack of water and cement hydration incomplete slurry pulverization, fall off, and then destroy the whole system.
At present, the general paste of polystyrene way has "box" method and "full of sticky method" two kinds. Among them "point box method suitable for flatness bad at the grass-roots level," full of sticky method "for flatness good base. Most of the buildings from the actual situation, the flatness is not enough, usually with a "box" method. But for high-rise buildings is recommended to use "full stick method", this is very beneficial to the safety of the EPS system, especially the brick veneer system. Although there are a lot of people according to building structural load calculation, think bond strength is greater than the negative wind pressure, brick veneer system is safe, but it's actually not the case. Therefore, paste of polystyrene "full stick method" should be adopted.
Cracking flexible plaster mortar in the external thermal insulation system plays a very important role, in the most easy to occur in the practical engineering problem is cracking. With its exterior insulation system is the main body of the lateral, so in order to reduce the outside temperature, humidity and rain on the negative impact of the require the use of mortar should have abhorred properties, such as water, impermeability and crack resistance. In general, most of the mortar are need to be adopted to disperse polymer powder, can significantly improve compressive strength of cement paste with different matrix, and improve the cement mortar of hydrophobic, flexural strength, flexural strength, abrasion resistance, mechanical stability and shock resistance, improve related to weather or water retention of the cement mortar water resistance, heat resistance, resistance to freezing and thawing and resistance to permeability, etc. According to the national industry standard, performance index of plastering mortars should comply with the requirements of table 2.