Performance of Thermal Insulation of Different Composite Walls and Roofs Materials Used for Energy Efficient Building Construction in Iraq

This study numerically involves the performance of thermal insulation of different types of composite walls and roofs to demonstrate the best model that can be used for energy-efficient building construction in Iraq.The mathematical model is solved by building its code using the Transmission Matrix Method in MATLAB software.The weather data of 21st July 2022 in Baghdad City/Iraq is selected as a test day.The wall types are selected:the first type consists of cement mortar,brick,and gypsum,the second type consists of cement mortar,brick,gypsum,and plaster and the third type consists of cement mortar,brick,gypsum,air cavity,and sheathing timber.The roof types are chosen:the first type consists of reinforced concrete,gypsum,and plaster,and the second type consists of the precast concrete flag,river sand,tar,reinforced concrete,gypsum,and plaster.The obtained solutions are compared with previous studies for the same city but with different types of walls and roofs.The findings display that the second and third types of walls reduce the entry heat flux by 4%and 10%as compared to the first type of wall.Also,the results indicate that the second type of roof reduces the entry heat flux by 21%as compared to the first type of roof.The results confirm that the best models of walls and roofs in Iraq are the third and second types,respectively,as compared to other models and hence,the performance of insulation material strongly depends on the materials used while building them.

Experimental study on axial compressive behaviors of prefabricated composite thermal insulation walls after single-side fire exposure

The axial bearing capacity of prefabricated composite walls composed of inner and outer concrete wythes,expandable polystyrene(EPS)boards and steel sleeve connectors is investigated.An experimental study on the axial bearing capacity of four prefabricated composite walls after fire treatment is carried out.Two of the prefabricated composite walls are normal-temperature specimens,and the others are treated with fire.The damage modes and crack development are observed,and the axial bearing capacity,lateral deformation of the specimens,and the concrete and reinforcing bar strain are tested.The results show that the ultimate bearing capacity of specimens after a fire is less than that of normal-temperature specimens;when the insulation board thicknesses are 40 mm and 60 mm,the decrease amplitudes are 20.8%and 16.8%,respectively.The maximum lateral deformation of specimens after a fire is greater than that of normal-temperature specimens,and under the same level of load,the lateral deformation increases as the insulation board thickness increases.Moreover,the strain values of the concrete and reinforcing bars of specimens after a fire are greater than those of normal-temperature specimens,and the strain values increase as the thickness of insulation board increases.

Wood plastic composites based wood wall’s structure and thermal insulation performance

In order to solve the problem of poor thermal insulation in the current wood-plastic building,two kinds of structural wood wall integrated with wood plastic composite(WPC)are designed,and the thermal insulation performances of the walls are studied.The results show that the WPC integrated wall with frame-shear structure has a good stability,and the excellent performance of the WPC can be fully realized.Wall studs and wall panels are important factors affecting the thermal performance of the walls.Wood plastic materials can meet the thermal performance requirements of the walls.The single-layer frame walls and double-layer frame walls integrated with the WPC both have a good thermal performance.According to‘Design Standard for Energy Efficiency of Public Buildings(GB 50189-2015)’,the heat transfer coefficient of the single-layer frame wall integrated with 20 mm thick WPC wall boards and WPC wall studs is 0.414 W/(m^(2)•K),which can meet the standard of wall thermal levelⅡt and is suitable for cold areas.The heat transfer coefficient of the double-layer frame wall integrated with 50 mm thick WPC wall panel and WPC wall studs is 0.207 W/(m^(2)•K),which can meet the standard of wall thermal levelⅠt and is suitable for severe cold areas.

Sound Insulation Performance of Structural Wood Wall Integrated with Wood Plastic Composite

The sound insulation performance is an important technical index for evaluating the physical property of the building wall.Three kinds of structural wood walls integrated with wood plastic composite(WPC)were designed.And the sound insulation performance of the walls was studied.The results showed that for the wall that constructed by the WPC as the wall studs,compared with the one that constructed by the pine wood as the wall studs,the deviation of their sound insulation was lower than±3 dB.The wall’s external panel material had significant effect on the wall’s sound insulation property,and the contribution of the wood-plastic panel to the sound insulation was much higher than that of the polyvinyl chloride(PVC)plastic hanging board.The surrounding sealing quality of the wall’s external panel material had an important influence on the sound insulation effect of the building wall,and the panel of the wood plastic interior wall had less influence on the sound insulation performance of the wall.Taking the sound-absorbing cotton or non-woven fabric as elastic strips was an effective technical measure to improve the sound insulation performance of the walls.The sound insulation was improved by 2.4 dB and 3.1dB respectively after the correction of pink noise spectrum,and increased by 2.8 dB and 3.6 dB respectively after the correction of traffic noise spectrum.

保温叠合剪力墙FRP连接件力学性能

以夹心保温叠合剪力墙为研究对象,研究螺纹型、矩形和六芒星状3种纤维增强复合材料连接件(FRP)在施工阶段和使用阶段下的抗剪力学性能,并且对三种FRP连接件在两个阶段下的破坏形态、抗拔承载力和荷载-位移曲线进行分析,结果表明:试件的破坏形态主要有混凝土锚固破坏,层间剪切破坏和断裂破坏。施工阶段下单根FRP连接件最终抗剪承载力在1.41~3.91 kN之间,使用阶段下单根FRP连接件最终的抗剪承载力在3.19~6.02 kN之间,根据理论公式得到的计算值与试验值对比可知,在两个阶段情况下3种连接件的安全系数均大于1,均有较大的安全储备,可以应用到实际工程中。

Dynamic performance and energy efficiency of reflective and insulative composite coating on building exterior wall

Reflective and insulative composite coatings are a new energy-saving material with high solar reflectance and extremely low thermal conductivity for buildings.The optimization and impact of high solar reflectance and low thermal conductivity on the insulating capacity of walls remain uncertain.This work investigates the dynamic thermal performance and energy efficiency of a reflective and insulative composite coating in regions with hot summer and warm winter.A simplified thermal resistance-heat capacitance model of an exterior building wall is established to predict thermal performance.The dynamic temperature and heat flow of the wall are predicted to reduce heat loss through the interior surface of the wall and compared to the conventional coating.The specific impact of the thermal conductivity and solar reflectance of the coating on the heat loss is further investigated to minimize heat loss of the wall.This research shows that the composite coating shows better performance on adjusting outdoor climate change than the other coating.Compared with cement,it reduces the maximum temperature of the exterior surface of the wall by 7.45°C,and the heat loss through the interior surface of the wall by 38%.The heat loss is reduced with the increase of solar reflectance and the reduction of thermal conductivity.The results can provide a useful reference and guidance for the application of reflective and insulative composite coating on building exterior wall to promote their energy-saving use on building envelopes.

Research on Building Exterior Wall Decoration and Its Energy Saving Optimization

This paper mainly uses the method of numerical simulation, and study thermal insulation and energy saving characteristics on the exterior walls of the building and analyze the optimal layout scheme of building exterior wall and thermal insulation system. Finally, the paper study optimal thickness of insulation materials. The paper elaborate scheme of the existing building energy-saving for exterior wall and the scope of application, the system structure and the construction technology. The results showed that： extruded benzene board that can be used for exterior insulation, frame structure filled with wall preferred ceramsite hollow block. The paper can provides reference selection of insulation for building external wall energy-saving transformation scheme.

装配式日光温室柔性复合墙体性能测试与分析

为解决装配式日光温室柔性墙体蓄热能力不足的问题,该研究通过在墙体内侧附加蓄热层的方式,设计了一种集蓄热、保温和防水多功能于一体的装配式柔性复合墙体。首先,通过对多种材料进行综合性能评估,筛选出优质的表层材料和保温材料,将其复合制成柔性保温墙体;其次,将水、沙子、相变水凝胶(phase change hydrogel,PCH)作为蓄热层固定在柔性保温墙体内侧,从而形成柔性复合墙体;最后,在4个模型温室中分别对墙体进行性能测试,以未附加蓄热层的柔性保温墙体为对照(CK),分析试验墙体的蓄热和保温性能。单一墙体材料的性能测试结果表明,表层材料中镀铝编织布、黑色淋膜毡抗拉性能好且不透水,断裂强力分别为1.06、0.56 kN,断裂伸长率分别为30.99%、65.91%;保温材料中再生棉、太空棉和空气柱保温效果较好且使用成本低,热阻值分别为0.30、0.50、0.76(m^(2)·℃)/W。柔性复合墙体的性能测试结果表明,所有处理中5 kg/m^(2) PCH柔性复合墙体的蓄热和保温性能最佳,热阻值为2.50(m^(2)·℃)/W,单位面积累计吸热量与放热量分别为1.48、1.13 MJ/m^(2);在典型晴天和阴天条件下,该处理的夜间室内平均温度分别比CK提高了3.08、1.87℃。上述分析结果表明,通过在柔性保温墙体内侧附加相变蓄热层的方式,能够增强墙体的蓄热和保温性能。研究结果可为今后装配式日光温室柔性复合墙体设计及材料选择提供理论依据。

HYGROTHERMAL PERFORMANCE ASSESSMENT OF ICF WALLS WITH DIFFERENT MOISTURE CONTROL STRATEGIES AND WALL DESIGNS

The initial high moisture content of concrete and the low vapor permeability of insu-lation layers on both sides of the concrete complicate the drying process of Insulated Concrete Forms(ICF).In order to facilitate the moisture transport and enhance the drying process,different moisture control stratcgics and wall designs can be implc-mented.The application of an air and vapor barrier is one of the most common moisture control stratcgics.In this paper,the impact of vapor permcance of an air and vapor barriers on the hygrothermal performance of an ICF wall in three differ cnt cold and wet climates is examined using a validated Hcat-Air-Moisture transfer model.The hygrothermal performance of an ICF wall assembly with different types of barriers and locations in the wall system for scveral wall designs is invcstigated.Results indicate that a smaller thickness of insulation on the outside facilitates remov-ing the moisture towards the outside and installing low permcance air/vapor barrier systems on the outside prohibits drying and drives the moisture to the inside.Our findings also show that with the proper sclection of insulation thickncss and vapor control stratcgy moisture-related problems can be avoided.

一种新型结构与保温一体化复合墙板节点试验

为解决复合墙板节点常见的保温板易燃、易脱落等棘手问题,并使其抗震性能良好。给出了一种新型的结构与保温一体化陶粒混凝土T型复合墙板节点。该复合墙板节点具有夹芯独特构造优势,主要表现在绿色节能,轻质高强,力学性能好,保温系统连接可靠,还能杜绝火灾的发生。通过对T型复合墙板节点进行抗震试验,分别研究了其滞回性能、破坏机理、承载及变形能力、延性、耗能、损伤等。结果表明:一体化复合墙板节点的破坏顺序为腹板-翼缘-节点核心区;薄弱位置主要发生在腹板脚部,混凝土被拉裂或压碎,钢筋被拉长或压弯等;节点核心区受力相对良好,安全储备充足;符合“强节点,弱构件”设计要求和墙板革新发展政策。延性系数大于3,墙板节点安全性能良好。通过损伤指标评估分析,了解了试件各阶段工作状态。

装配式带夹芯保温槽型玻璃钢-钢板-槽钢-混凝土组合剪力墙轴压性能研究

提出一种装配式带夹芯保温槽型玻璃钢-钢板-槽钢-混凝土组合剪力墙,设计3个具有不同配筋形式和混凝土种类的墙板试件进行轴心受压试验,获得墙板在轴压作用下的破坏模式、荷载-位移曲线、荷载-应变曲线、承载力储备系数、延性系数、材料利用率等性能指标。通过ABAQUS有限元分析软件对墙板进行参数化分析,研究内嵌钢板强度和厚度对其轴压性能的影响。结果表明,墙板具有良好的承载力储备能力和延性性能;混凝土中掺入1%体积比的钢纤维可显著提高墙板内混凝土的抗拉性能,使混凝土强度得到更加充分的利用,布置钢筋可以显著提高墙板延性;墙板的承载力和延性随内嵌钢板厚度和强度的增加而增大,强度为Q355、厚度为4、6mm时,墙板材料利用率更高。提出适用于该类墙板的轴压承载力设计公式,考虑钢板屈曲和截面组合效应的墙板轴心受压承载力设计公式计算结果较精确。

预制内外复合保温模壳拼装墙体热工性能研究

为探究预制内外复合保温模壳拼装墙体结构中的卡板连接件对墙体热工性能的影响,通过热工理论计算、试验研究、ANSYS有限元热分析模拟软件3种方法,对比分析了无连接件、不同数量连接件以及双面抹灰不同条件下墙体的传热系数。结果表明:在无连接件条件下,实际墙体热工试验测试值与热工理论计算值的误差较小;连接件数量越多,热桥效应越明显,墙体的热工性能越差;采用有限元模拟软件对墙体进行热工设计结果较精确,可作为设计依据;研究结果可为模壳拼装墙体在超低能耗建筑的应用及能耗分析提供借鉴。

复合保温板与加气混凝土砌块墙体一体化施工力学性能研究

针对复合保温板与砌块填充墙连接的安全性,采用HC-MD60高精度铆钉拉拔仪,进行锚栓抗拉承载力和复合保温板拉伸黏结强度现场原位检测试验。测试结果表明:锚栓抗拉承载力平均值为2.345 kN,复合保温板表面抗裂加强层与保温芯材之间的黏结强度平均值为0.17 MPa,复合保温板内侧黏接层与砌块墙体黏结强度为0.1 MPa,黏锚结合的力学性能满足DB/T 29-281—2020《天津市外模板现浇混凝土复合保温系统应用技术规范》要求。

现浇混凝土保温复合填充墙与剪力墙弱连接节点分析研究

近些年剪力墙住宅愈发增多,研究提出了一种薄弱位置的节点设计方案,该节点可用于剪力墙结构中部分现浇混凝土保温复合填充墙与剪力墙、梁等结构构件的弱连接,同时还可利用土木结构非线性软件进行有限元计算分析。结果表明:通过对比弱连接节点及结构构件的剪应力可知,混凝土现浇外墙与周边结构构件的弱连接剪应力远大于主体混凝土梁在对应工况下的剪应力,该弱连接节点可以满足先于主体混凝土梁破坏的要求,故节点构造切实可行。

复合保温外墙体系施工技术研究

随着我国能源消耗的不断增加,工程方对居住建筑节能的要求也在不断提高。当前,我国的建筑节能设计标准已经从节能50%以上到了第一阶段节能幅度大于75%以上的要求,总之,建筑节能设计已成为行业发展的当务之急。针对外墙施工存在经济效益差的问题,开展复合保温外墙体系施工技术研究。提出一种全新的施工方案,其中包括:墙体骨架和面板安装、泡沫混凝土填充浇筑和一体化保温板复合外墙保温体系施工。通过对新施工技术的经济效益分析得出,新技术更具经济效益,每平米的造价更低。

严寒地区墙体冻融条件下热湿特性研究

为研究严寒地区典型墙体冻融条件下的热湿变化,以哈尔滨地区为例,通过Delphin模拟分析了相同传热系数下,不同基层材料的4种外保温复合墙体内部含水量、含冰量、湿累积和导热系数的变化特征。研究结果表明,4种墙体的结冰只发生在保温层,含冰量基本呈逐年递减;基层材料为加气和泡沫混凝土的复合墙体,其湿累积量在前4年显著下降;4种墙体保温层导热系数在含湿状态下相较于干燥状态的增幅分别为1.06、1.15、1.16、1.12倍,而混凝土层的导热系数增幅则分别为0.02、0.38、2.61、4.36倍。研究可为严寒地区典型墙体的热湿特性分析和节能设计提供参考。

组合砌体墙损伤红外热像检测方法研究

轻钢芯柱-保温夹层组合砌体墙的裸露部分受自然因素影响易出现墙体损伤,影响墙体的使用寿命,为此提出组合砌体墙损伤红外热像检测方法。该方法通过超声红外热成像技术,获取组合砌体墙损伤的红外图像,基于双边滤波方法,提升了组合砌体墙损伤图像的低照度;基于图像处理技术和形态学检测技术,对组合砌体墙损伤边缘进行精准提取,确定损伤程度,实现精确检测。结果表明:当图像数量为20~100张时,该方法检测的mAP值与召回率均高于90.00%,墙体损伤检测较为完整且损伤支线明显,直观表现了检测效果;准确度均高于95.00%,提升了墙体损伤检测方法的检测完整度;平均IoU均高于85.00%,有效提高了损伤区域与标定区域之间的重叠率。该方法的检测效果好、性能高。

建筑外墙用新型复合保温板力学性能试验研究

为研究新型复合保温板的受力性能,设计进行不同保温芯材复合保温模板的力学性能试验。结果表明:挤塑聚苯复合保温板在压缩过程中试件四周出现褶皱,但无明显裂纹;岩棉条复合保温板在受压过程中,岩棉纤维发生弯曲或折断,成条状相互分离;插丝岩棉复合保温板随压力作用,纤维之间挤压密实,表现出较强的抗压能力;石墨聚苯复合保温板受压过程中四周出现褶皱;在一定范围内随保温芯材厚度增加,复合保温板的弹性模量和压缩强度增加,挤塑聚苯板保温芯材的弹性模量和压缩强度较石墨聚苯板保温芯材高。

带挑檐的钢筋桁架复合保温剪力墙抗震性能试验研究

提出了一种带挑檐的钢筋桁架复合保温剪力墙,设计了两个足尺的剪力墙试验构件,通过对其进行拟静力抗震试验,分析了这种墙体的的破坏特征、滞回性能、承载力、延性、强度和刚度退化以及墙体的耗能能力。结果表明:钢筋桁架复合保温剪力墙裂缝分布基本相同,均呈现弯曲破坏特征,设置挑檐的试件裂缝延伸至保温板外保护层,结构层与保温层有很好的整体工作性能;未设置挑檐的试件保温板外保护层无裂缝产生,整体工作性能较差。设置挑檐的钢筋桁架复合保温剪力墙峰值荷载、位移延性、累计耗能提高,具有良好的承载性能和延性性能,滞回曲线更加饱满,刚度退化得到减缓,说明设置挑檐提高了钢筋桁架复合保温剪力墙的整体抗震性能。

装配式预制混凝土复合墙板外墙保温设计研究

为了提升装配式预制混凝土复合墙板的保温效果,文中以某住宅楼为例,对装配式预制混凝土复合墙板的外墙保温设计方案、刚性连接处热桥处理、连接处保温加强以及保温外墙防水设计进行分析,并对装配式预制混凝土复合墙板的防水效果和保温效果进行评价。结果表明,所有监测点的室内壁面温度均高于大气温度,室内壁面温度波动状况远小于室外,装配式建筑结构具有良好的储温效果;各检测点的热流密度波动状态保持一致,各监测点之间的热流密度最大差值为0.92 W/m^(2),装配式预制混凝土复合墙板具有良好的保温及防水效果。