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.

Tree‑Inspired Structurally Graded Aerogel with Synergistic Water,Salt,and Thermal Transport for High‑Salinity Solar‑Powered Evaporation

Solar-powered interfacial evaporation is an energy-efficient solution for water scarcity.It requires solar absorbers to facilitate upward water transport and limit the heat to the surface for efficient evaporation.Furthermore,downward salt ion transport is also desired to prevent salt accumulation.However,achieving simultaneously fast water uptake,downward salt transport,and heat localization is challenging due to highly coupled water,mass,and thermal transport.Here,we develop a structurally graded aerogel inspired by tree transport systems to collectively optimize water,salt,and thermal transport.The arched aerogel features root-like,fan-shaped microchannels for rapid water uptake and downward salt diffusion,and horizontally aligned pores near the surface for heat localization through maximizing solar absorption and minimizing conductive heat loss.These structural characteristics gave rise to consistent evaporation rates of 2.09 kg m^(-2) h^(-1) under one-sun illumination in a 3.5 wt%NaCl solution for 7 days without degradation.Even in a high-salinity solution of 20 wt%NaCl,the evaporation rates maintained stable at 1.94 kg m^(-2) h^(-1) for 8 h without salt crystal formation.This work offers a novel microstructural design to address the complex interplay of water,salt,and thermal transport.

A lightweight and high compressive resistance thermal insulation material with dual-network structure

Ceramic fibrous aerogels are highly desirable for thermal management materials due to their high porosity,excellent elasticity,thermal conductivity,and good thermal resistance.However,the fabrication of nanofibrous aerogel with super-elasticity and good shape retention at the same time has remained challenging.To meet the requirements,a novel anisotropy nanofibrous-granular aerogel with a quasi-layered multi-arch-like and hierarchical-cellular structure is designed and prepared by vacuum-filtration-assisted freeze-drying and sintering.The quasi-layered multi-arch and flexible nanofibers endowed the aerogels with excellent mechanical robustness(ultimate stress up to 60 kPa with strain 60%)and super-elasticity with recoverable compression strain up to 60%.The introduced SiO_(2) aerogel nanoparticles and nanofibers are assembled into an arch-like structure and become the connection point of adjacent nanofibers,which endows low thermal conductivity(0.024 mW/(m·K))of composite aerogel.This novel strategy provides a fresh perspective for the preparation of nanofibrous aerogel with robust mechanical in thermal insulation and other fields.

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。

BN-石墨烯-BN夹层式结构的ABS基复合材料导热绝缘性能

为解决石墨烯/ABS复合材料导热不绝缘,采用夹层式结构制备ABS基导热绝缘材料。通过混炼分别得到石墨烯/ABS、六方氮化硼(hBN)/ABS复合材料,再将hBN/ABS对石墨烯/ABS进行包覆,得到了hBN/ABS—石墨烯/ABS—hBN/ABS夹层式结构的导热绝缘材料。研究了石墨烯含量和夹层厚度对ABS基导热绝缘材料标准试样的热导率、电阻率的影响,发现,包覆了hBN/ABS绝缘层后的夹层式结构试样,石墨烯填料对导热性能的提升作用幅度减小,此时,材料受氮化硼/ABS绝缘层热传导的影响较大,与改性前的ABS相比,复合材料导热性能得到较大的改善,同时,复合材料阻值达1×1010数量级,成为绝缘体。

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。

发泡水泥板的应用背景、现状及前景概述

为深层次、全面了解发泡水泥板诞生背景、应用现状和发展前景,本文对发泡水泥板应用背景、市场需求、技术标准沿变、整体性能、综合成本、应用现状、发展前景进行全方位、多角度、深层次剖析。综合认为:尽管发泡水泥板具有隔热、防火(A1级)、环保、抗老化、强度高等优点,但其研发技术壁垒低,加上劣质产品挡道、厂家恶性竞争等恶劣现象,致使其市场容纳空间已非常狭小。本文将为建筑从业人员全面了解发泡水泥板的“来龙去脉”和实时动态提供最新现实科学依据,为科研工作者研发新型建筑保温材料提供更多理论科学依据。

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.

全预制框架结构装配式混凝土建筑复合外墙“干式”建造优化研究

目前受传统串行建筑运作模式影响,部分装配式项目依然执行“常规设计+二次拆分”,进而引起拆分的装配单元类型较多或拆分不干净现象,而在承继以上问题的同时,混凝土框架结构复合外墙出现了装配单元与结构体系之间“直接”连接的连接件暴露问题。基于此,以中国西部科技创新港科创基地7号楼(西安交通大学人居环境研究院)为例,首先对设计进行了修正,并建立了预埋龙骨的干式机械连接方式,从而使复合外墙与结构体系的干式连接得以优化与修正。

内/外隔热复合结构炸药装药快速烤燃热防护效应

为了研究快速烤燃(火烧)条件下炸药装药内/外隔热复合结构(内隔热材料/外阻燃材料)的热防护效应,对多种内/外隔热复合结构的炸药装药进行多点测温快速烤燃试验,得到火焰场和炸药装药各测点的温度-时间曲线及装药点火响应时间。开展内/外隔热复合结构炸药装药快速烤燃数值模拟,获得内/外隔热复合结构对装药快速烤燃点火响应时间的影响规律。研究结果表明:在快速烤燃过程中,外阻燃材料由于火烧变性存在导热增强及隔热减弱效应,在数值模拟中需考虑该效应;无论使用单独的隔热/阻燃材料还是使用内/外隔热复合结构,炸药装药的点火响应时间均随着材料涂覆厚度增加而延后,其中内/外隔热复合结构具有更好的热防护能力;点火位置均发生在装药端面棱角处,装药点火后反应烈度不受内/外隔热复合结构影响,反应等级均为爆燃;对于一定热防护性能范围内的隔热阻燃材料,壳体外表面涂层材料是耐高温纳米隔热材料、壳体内表面涂层材料是高效隔热防护材料时复合结构的隔热效果最好,并且当需求的隔热效果给定时,可考虑优先增加壳体外表面涂层的涂覆厚度,实现以最小涂覆厚度的内/外隔热复合结构满足所需的隔热效果。研究成果可为提升弹药热安全性设计提供参考。

相变蓄热对光伏相变复合围护结构隔热及发电性能的影响

基于光伏发电和相变蓄热耦合特性,提出了光伏相变复合建筑围护结构,并进一步分析相变蓄热对复合围护结构性能的影响规律。首先构建光伏相变复合围护结构热流传递模型,然后探究相变层结构位置、相变温度以及相变厚度对其发电能力和隔热效果的影响。在此基础上,通过对比传统围护结构和复合围护结构的热工特性,阐述复合围护结构调节室内环境负荷及节能潜力。研究表明,相变蓄热对于光伏相变复合围护结构发电和隔热性能具有较大影响。相变材料越靠近室内其隔热效果越好,室内温度表现出向相变温度靠近的趋势;相变材料靠近光伏板意味着可以更充分地储存热量,光伏发电量也就越高。其中相变材料靠近光伏板时发电量为1263.06 J,较光伏围护结构有明显提升。同时相变材料的厚度在40 mm时发电量达到最大值,较10 mm时的工况提升了0.55%。此外,在一个运行周期内,光伏相变复合围护结构显著降低了建筑冷负荷,表现出较好的隔热与节能效果。

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。

粮食平房仓“结构-隔热”一体化墙板热工性能研究

为了提高散装粮食平房仓墙体保温隔热性能,提出了一种新型“结构-隔热”一体化墙板(SIW墙板)。通过试验和数值模拟,分析了保温板厚度、连接件等对SIW墙板热工性能的影响,揭示了内、外叶墙板温度、热流密度随时间的变化规律,得到了SIW墙板的传热系数,基于传热系数指标开展了SIW墙板在不同储粮生态区的适用性评价。结果表明:相较于传统平房仓砖砌墙体,保温板厚度为50 mm和80 mm的SIW墙板传热系数分别降低了45.81%和56.13%;GFRP连接件在SIW墙板中的热桥效应不显著,对墙板温度场的影响较小;相较于保温板厚度为50 mm的SIW墙板,80 mm厚的SIW墙板能满足3个储粮生态区对粮食平房仓墙体传热性能的要求。

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.

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。

大居市属保障房项目外墙外保温系统高坠风险分析及维修治理方法探讨

近年来,建筑外墙外保温系统的开裂、空鼓和高坠事件时有发生,成为社会关注的焦点问题。文章以典型某大居市属保障房项目为例,对建筑外墙外保温系统构造、黏结强度、外墙面损伤、空鼓及材料抗压强度进行检测,分析采用无机保温砂浆外保温系统的外墙产生开裂、空鼓乃至脱落的原因;在此基础上,提出与之相对应的维修方法、技术要点和保障措施。

建筑物外墙外保温材料的选择及施工技术分析研究

本文以外墙外保温材料为基础,主要研究了外墙外保温技术及外墙外保温隔热材料。分析了外墙外保温材料的品种及特征,剖析对比了外墙外保温材料,总结出了最方便被人们所运用的材料和技术并指出了其缺点,重点分析了常见的外墙外保温施工技术,提出了外墙外保温施工质量控制,为建筑外墙保温节能事业提出有用的技术支持。

夹芯无机保温外墙板热工性能研究

为分析夹芯无机保温外墙板热工性能,文中建立了夹芯无机保温外墙板仿真模型,分析不同墙厚及窗墙比对夹杂无机保温外墙平均传热系数的影响。结果表明,各构件位置的最低温度均高于露点温度,证实上述位置具有良好的保温性能;模拟能量随墙体厚度增加的降低速率为0.585 W/mm,模拟传热系数随墙体厚度增加的降低速率为0.001 [W/(m^(2)·K)]/mm;计算传系数与模拟传热系数值两者的误差在5%以内,证实所建模型的准确性。所有窗墙比下,凸窗的传热系数高于普通窗的传热系数,但是其传热系数的增加速率低于普通窗的传热系数增加速率。