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外墙保温材料体系分析一
华东保温商城 / 2014-10-15
外墙外保温,是将保温隔热体系置于外墙外侧,使建筑达到保温的施工方法。
Exterior insulation, thermal insulation system on external wall of the lateral, to building construction method of the heat preservation.
由于外保温是将保温隔热体系置于外墙外侧,从而使主体结构所受温差作用大幅度下降,温度变形减小,对结构墙体起到保护作用并可有效阻断冷(热)桥,有利于结构寿命的延长。
Because of external thermal insulation is the thermal insulation system on external wall of the lateral, so that the structure of main body temperature difference effect, a big drop in temperature deformation is reduced, the structure of wall protection and can effectively block the cold (hot) bridge, is conducive to longevity.
然而,由于外保温隔热体系被置于外墙外侧,直接承受来自自然界的各种因素影响,因此对外墙外保温体系提出了更高的要求。就太阳辐射及环境温度变化对其影响来说,至于保温层之上的抗裂防护层只有3mm~20mm,且保温材料具有较大的热阻,因此在的热量相同的情况下,外保温抗裂保护层温度变化速度比无保温情况下主体外倾温度变化速度提高8~30倍。因此抗裂防护层的柔韧性和耐候性对外保温体系的抗裂性能起着关键的作用。
However, due to the external thermal insulation system is placed in the outer wall of the lateral, take direct from a variety of factors affect the nature, so the external wall external thermal insulation system put forward higher requirements. On solar radiation and ambient temperature change for its impact, as for the thermal insulation layer on top of the crack resistance of protective layer is only 3 mm to 20 mm, thermal resistance and thermal insulation material has larger, so under the same heat, external thermal insulation anti-crack layer temperature change faster than subject extraversion without heat preservation temperature change speed increased by 8 ~ 30 times. So the cracking of protective layer flexibility and weatherability anti-cracking performance of external thermal insulation system plays a key role.
细数各保温系统的“硬伤”
To count the thermal insulation system of "line"
1、聚苯板薄摸灰外保温系统
1, polystyrene board thin touch ash external thermal insulation system
这类外保温隔热系统通常采用粘贴法将聚苯板固定在墙体的外侧,然后再保温板上抹抹面砂浆并将增强网铺压在抹面砂浆中,目前,此类做法很常见,然而出现裂缝的也非常多。从抗裂保护层受热应力的因素上看,该体系聚苯板保温层仅是3mm的抗裂砂浆复合网格布,膨胀聚苯板的导热系数为0.042W/m.K,而抗裂砂浆的导热系数为0.932W/m.K,两材料的导热系数相差22倍。由于聚苯板保温隔热层热阻很大从而使保护层的热量不易通过传导扩散,因此当受太阳直射时热量积聚在抗裂砂浆层,其表面温度将高达50℃(大连地区),遇突然降雨将温则温度会降至15℃左右,温差可达35℃,这样的温差变化以及受昼夜和季节室外气温的影响,对抹灰砂浆的柔韧性和网格布的耐久性提出了相当高的要求。另外一个应该考虑的因素是当聚苯板的温度超过70℃时,聚苯板会产生不可逆热收缩变形,造成较为严重的开裂变形,这种情况在高温干燥地区更为明显。
This kind of external thermal insulation system usually adopt paste method will polyphenyl plate fixed on the outer edge of the wall, and then on the insulation board of plastering mortar and pressure will increase net shop in the mortar, at present, this kind of practice is very common, but cracks are also very much. Look from the anti-cracking cover factor of heat stress, the system of polystyrene insulation layer is only 3 mm anti-crack mortar composite grid cloth, the coefficient of thermal conductivity of eps board is 0.042 W/m.K, and the coefficient of thermal conductivity of anti-crack mortar is 0.932 W/m.K, coefficient of thermal conductivity of two materials is 22 times. Because of polystyrene thermal insulation layer of thermal resistance is very big so that the protective layer of heat by conduction diffusion not easily, so when the sun and heat accumulation in the anti-crack mortar layer, the surface temperature will be up to 50 ℃ (dalian), when all of a sudden rain will warm temperature will drop to about 15 ℃, temperature difference can be up to 35 ℃, the temperature change and influenced by circadian and seasonal temperature outdoor, flexibility and durability of grid cloth of plaster mortar put forward very high requirements. Another factor should be considered when the temperature of the polystyrene is over 70 ℃, polystyrene produce irreversible thermal contraction deformation, cause more severe cracking deformation, this situation is more obvious in the high temperature dry areas.
2、水泥砂浆厚抹灰钢丝网架保温板外保温
2, thick wire rack insulation board exterior insulation plastering cement mortar
这类外保温隔热通常采用带有钢丝网架的聚苯板作为主体保温隔热材料,分为钢丝网穿透聚苯板和不穿透聚苯板两种类型。钢丝网穿透聚苯板的钢丝网架,聚苯板施工时通过预先浇混凝土整体一次性浇筑固定在基层墙体上,不穿透聚苯板的采用机械锚固的方式固定在基层墙体上,面层均采用20mm~30mm的普通砂浆找平。由于该类体系采用厚抹灰水泥砂浆做法,开裂现象比较普遍,原因如下:
This kind of external thermal insulation is usually used with a wire rack of polystyrene as main body heat preservation and heat insulation material, divided into steel mesh through two types of polystyrene and not through polyphony board. Wire rack, wire mesh through polyphony board of polystyrene by pouring concrete in advance during the construction of the overall disposable pouring fixed on the wall at the grass-roots level, not penetrate of polystyrene with the method of mechanical anchor fixed on the wall at the grass-roots level, surface adopt ordinary mortar leveling 20 mm to 30 mm. Because this system adopts thick plastering cement mortar, cracking phenomenon is common, and here's why:
1)普通水泥砂浆自身易产生各种收缩变形,并且存在强度增长周期短、体积收缩周期长的矛盾,在约束条件下,当体积收缩形成的拉应力超过水泥砂浆的抗拉强度时,就会出现裂缝。
1) themselves are prone to all kinds of ordinary cement mortar contraction deformation, and there is strength growth cycle is short, the volume contraction cycle long, under the constraint condition, when the volume shrinkage of tensile stress exceeds the tensile strength of cement mortar, cracks will occur.
处于保温层保护下的主体结构受温度变形影响较小,而20~30mm的找平砂浆处于热阻很大的聚苯板的外侧,因策受环境温度影响而产生较大变形。聚苯板两侧的水泥材质受环境温差影响而产生较大相对变形差,引起开裂。
In the thermal insulation layer under the protection of the main structure is influenced by temperature deformation is small, and 20 ~ 30 mm leveling mortar at the outer edge of the great of polystyrene thermal resistance, large deformation due to policy is influenced by environmental temperature. Polystyrene plate on both sides of the cement material affected by the environment temperature to produce a larger relative deformation is poor, cause craze.
另外由于保温隔热板平整度很难控制,会造成找平抹灰厚度的不均,造成局部收缩和温差应力不均从而引起裂缝。
In addition due to thermal insulation plate flatness difficult to control, will cause the leveling uneven thickness of plaster, cause local uneven shrinkage and temperature difference stress causing cracks.
2)配筋不合理引起裂缝。
2) reinforcement is not reasonable cause cracks.
钢丝网架在在水泥砂浆中的位置相当于单面配筋方式,且靠近保温隔热层。在正负风压、热胀冷缩、干缩湿涨及地震等作用都是双向或多向。该种方式的配筋对靠近外墙饰面应力的分散作用很有限,起不到应有的抗裂作用。四角钢网配筋对抵抗和分散与钢丝网网丝同向的应力具有良好的效果,但在网孔对角线方向无筋,因此对抵抗和分散网孔对角线方向的应力左用有限。从而易产生沿四角网对角线方向的裂缝,另外,四角钢网的十字交叉处水泥砂浆不易完全充分握裹,使水泥砂浆与钢网不能成为共同受力。
Wire rack in a place in the cement mortar is equivalent to single way of reinforcement, and close to the thermal insulation layer. In positive and negative wind pressure, heat bilges cold shrink, drying shrinkage is wet effect such as inflation and earthquake are two-way or multidirectional. The method of reinforcement of exterior walls facing stress dispersion effect is limited, don't crack. Four Angle steel mesh reinforcement to resist and dispersed and the stress of the steel wire net synthetic has a good effect, but in mesh diagonal reinforcement, thus to resistance and disperse stress to mesh the diagonal direction left with limited. To easy generation along the diagonal corners net direction of crack, in addition, four Angle steel net cross intersections cement mortar bond, not easy to complete the cement mortar stress together with the stencil can't be.
3)不完全外保温引起的裂缝。
3) the external thermal insulation cracks caused by incomplete.
在外墙保温中,我们经常注重整体墙面的保温,然而却忽略了女儿墙、雨篷、老虎窗、凸窗、外阳台等部位的保温,而使此部分出现开裂或者降低使用寿命。
In the outer wall heat preservation, we often pay attention to the insulation of the whole metope, but ignores the parapet, awning, tiger parts such as outside the window, bay window, balcony of insulation, and make this part of the fracture or reduce the service life.
在保温层与其他材料的材质变换处,因为保温层与其他材料的材质的密度相差过大,这就决定了材质间的弹性模量和线性膨胀系数也不相同,在温度应力作用下的变形也不同,极容易在这些部位产生面层的裂缝。同时还应该考虑防水处理,防止水分侵入到保温体系内,避免因冻涨作用而导致体系的破坏,影响体系的正常使用寿命和体系的耐久性。
In the insulation material transformation with other materials, because the density of the material of insulation and other materials vary too much, it determines the elastic modulus and linear coefficient of expansion between the material is not the same, the temperature stress under the action of deformation is also different, very easy to produce surface cracks in these areas. Waterproof processing must also be considered at the same time, to prevent moisture intrusion in the insulation system, to avoid system damage caused by the freezing of role, affect the normal service life of the system and the durability of the system.
3、无网聚苯板外保温
3, no mesh polystyrene board exterior insulation
从构造设计上看,直接在玻纤网布复合抹灰砂浆的无网聚苯板外保温外面粘贴面砖是不合理的。一方面,从受力状况看,应用于外保温的聚苯板的通常采用点粘法,粘结面积35%左右,而聚苯板本身具有受力变形的特性,由聚苯板直接承受面砖饰面层(包括粘结砂浆)荷载,必然会发生徐变,短期或许不会发生严重事故,但长期的变形将导致受力的失衡从而引发开裂甚至脱落。另一方面,从抗风压性上看,粘贴聚苯板外保温体系存在空腔,抗风压尤其是抗负风压的性能差,会出现在刮大风时聚苯板刮落事件。第三,从防火性能上看,体系本身就存在整体连通的空气层,火灾时很容易形成“引火通道”,使火灾迅速蔓延。聚苯板外墙外保温体系在高温辐射下很快收缩、熔结,在明火状态下燃烧,即在火灾发生时,聚苯板外墙外保温体系将很快遭到破坏。从这个意义上说,在聚苯板外保温体系面层粘贴面砖的做法是非常危险的,火灾状态下聚苯板在受热后严重变形,使面砖层丧失依托,引起面砖层整体脱落造成人员伤害。
Look from structural design, directly in the glass fiber mesh cloth composite mesh free of polystyrene board exterior insulation plastering mortar paste outside brick is not reasonable. On the one hand, from the stress state, the application of external thermal insulation of polystyrene usually USES point sticking method, bonding area of about 35%, and the eps board itself has the characteristics of stressed deformation directly by the eps board brick act the role of surface (including bonding mortar) under load, creep, is bound to happen in the short term may not be a serious accident, but the long-term deformation of the imbalance will lead to stress triggering crack or even fall off. On the other hand, from the point of view of the wind pressure resistance, cavity paste polystyrene board exterior insulation system, resistance to wind pressure, especially the negative wind pressure resistance is poor, there will be a polystyrene scraping events in the wind. Third, from the point of view of fire prevention performance, the system itself is a connected whole air layer, fire is easy to form the "firing channel", make the fire spread quickly. Polystyrene board exterior insulation system under the radiation of high temperature shrinkage, sinter soon, in the condition of open flame burning, namely when the fire broke out, polystyrene board exterior insulation system will soon be destroyed. In this sense, the surface paste tile polystyrene board exterior insulation system is very dangerous, when heated fire condition of polystyrene serious distortion, loss depends on the brick layers, the overall loss caused injuries caused brick layer.
正确把脉,对症下药
Correct pulse, suit the remedy to the case
以上都是外墙保温系统在设计、施工等过程中的不当,而造成施工质量的问题。那么,如何才能使建筑保温做到既满足保温要求,又满足建筑施工质量要求呢?
Above is exterior wall thermal insulation system in the process of design, construction and other improper, caused by the construction quality problem. So, how can we make do not only satisfy the requirement insulation, building insulation and meet the requirements of the construction quality?
 

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