Effect of hydrophilic admixtures on moisture and heat transport and storage parameters of mineral wool

Water vapor diffusion coefficient, liquid moisture diffusivity, adsorption isotherm, water retention curve, thermal conductivity and specific heat capacity of two new hydrophilic mineral wool materials are determined in the paper. For the sake of comparison, the same parameters are also measured for two hydrophobic mineral wool materials and two mineral wool materials without any specific admixtures. It is shown that the thermal properties of hydrophilic materials and their water vapor transport and storage properties are very similar to common mineral wool but their liquid water transport and water storage parameters are significantly enhanced compared to the reference materials.     

离心玻璃棉热湿传递特性实验研究

离心玻璃棉具有良好的保温隔热性能,被广泛用于建筑保温技术。为了研究夏热冬冷地区用于墙体内保温的离心玻璃棉热湿传递特性,设计了一套实验装置,通过实验测试了特定温湿度条件下离心玻璃棉的水蒸气渗透性能,研究了温度对离心玻璃棉湿传递过程的影响,并验证了一维稳态传热传质模型对离心玻璃棉保温材料的适用性。实验结果表明,离心玻璃棉内部所传递的湿流密度随着水蒸气分压力差的增加而增大;其水蒸气渗透系数值受水蒸气分压力差的影响较小;而且在特定的温湿度范围内,温度对离心玻璃棉的湿传递过程几乎没有影响。     

岩棉外墙保温体系耐久性能研究

外墙外保温是一种有效的保温形式,保温层材料岩棉以其高透气性、高防火性能、高隔音吸声性被广泛应用。本文以建于70年代并于90年代进行既有建筑岩棉外保温改造的两幢四层砖混结构住宅楼为实例,对其体系外墙面的裂缝进行现状调查,全面的测试外墙热工性能,并通过实体取样对材料当前的物理性能进行检测。研究表明,在岩棉外墙保温设计施工时所采用的多种防裂缝技术措施,可以有效的减少外墙裂缝;使用20年的岩棉外墙保温体系保温性能稳定;在外设保护层没有遭到破坏的情况下,岩棉板本身的物理性能基本没有发生变化,具有很好的耐久性。该研究为岩棉外墙保温体系的进一步推广与应用提供依据。     

无机绝热材料导热系数影响因素的研究

玻璃棉和岩棉是无机绝热材料中具有代表性的产品。本文对不同密度、温度和相对湿度条件下玻璃棉和岩棉的导热系数变化规律进行了系统研究。结果表明,玻璃棉和岩棉的导热系数随着密度的增大而逐渐减小。随着测试温度的升高,玻璃棉板和岩棉板的导热系数逐渐增大且其导热系数随温度呈线性关系。玻璃棉板和岩棉板的导热系数随相对湿度的增大呈现增大的趋势,玻璃棉板和岩棉板属于吸湿性材料,随着相对湿度的增大,水分进入材料的孔隙导致保温绝热性能下降。     

Effect of cracks on hygric and thermal characteristics of concrete

The effect of cracks on the moisture and heat transport and storage properties, basic physical properties and compressive strength of six different types of high performance concrete is analyzed in the paper. The cracks in the material specimens are randomly distributed, imposed by thermal treatment. Experimental results show that the presence of cracks affects all hygric and thermal parameters except for the specific heat capacity in quite a significant way. Also, the effects of microsilica addition and of the size and presence of aggregates are important. The liquid water transport is influenced by cracks, microsilica and aggregates in the most remarkable way, together with the compressive strength. Water vapor transport parameters, water sorption parameters, thermal conductivity and open porosity are also subject of significant changes and can indicate the damage induced by cracks with a sufficient sensitivity.     

Hydric, thermal and mechanical properties of self-compacting concrete containing different fillers

Water vapor diffusion coefficient, water absorption coefficient, water permeability, thermal conductivity, compressive strength and freeze resistance properties of two self-compacting concretes (SCC) containing limestone filler and fly ash are determined in the paper. The results indicate that strength development is faster in the material containing limestone filler but after 90 days the strength values in both materials are almost the same. Liquid water transport and heat transport are faster in SCC with limestone filler while the water vapor transport is faster in the material containing fly ash. This corresponds well with the much better freeze resistance of the material with fly ash compared to that with limestone filler and with the results of mercury intrusion porosimetry.     

Experimental study of parameters influencing mechanical properties of hemp concretes

Hemp concrete is a multifunctional ecological material used in buildings. Due to its high porosity (about 80% in volume), it presents an “atypical” mechanical behavior and its thermal and acoustic properties are particularly interesting. It is today possible to design this material according to the required use. This paper focuses on the mechanical properties of hemp concrete. It is shown that extreme curing conditions (30%, 75% and 98% RH) are prejudicial to the mechanical setting of the hydraulic binders whereas only high relative humidity disrupts the one of the air lime-based binder. It is also established that the binder content hugely influences the setting and hardening of the material. Finally, according to the hemp particle size, it appears that small particles (about 3 mm in length) lead to reduce the porosity and consequently the setting process of hemp concrete as compared to concrete manufactured with large particles (about 9 mm).     

Modelling of hysteresis influence on mass transfer in building materials

The processes of mass transfer in the material influence not only the conditions within the material but also inside the connected air spaces. A new module for precise representation of mass transfer in materials in contact with the indoor air, called Humi-mur, was elaborated and validated in this work. It allows for the precise representation of sorption isotherm and vapour permeability dependence on relative humidity. Also the sorption curve hysteresis has been implemented. The new module was then applied to estimate the sensitivity of the results to uncertainty in measured material properties and the impact of hysteresis effect. Reasonable estimation of experimental uncertainty resulted in the deviation of approximately 6% in the calculated results. Hysteresis quite strongly influences the dynamic behaviour of materials. Concerning hysteresis in the sorption isotherm, we showed that the average of the adsorption and desorption equations is a reasonable approximation of mean behaviour for coarse calculation. In case when precise results of the relative humidity (absolute humidity) are needed, the hysteresis effect should be taken into account.     

外墙保温用保温板关键性能调研

参考JG 149—2003规定对典型外保温板材分别进行了常规性能测试,并对岩棉板、玻璃棉板、矿棉板类无机板材进行了高温稳定性和碱稳定性测试。探讨了其作为防火隔离带材料的可行性。针对市面上涌现出的吸水率较大的保温板材,课题组选择岩棉板、玻璃棉板、玻化微珠保温板、酚醛板作为研究对象,进行了不同含水率下的导热系数测试。拟通过试验结果真实反应当前保温板材的性能,给外墙保温板材的正确使用提供一定指导。     

托架式岩棉板薄抹灰外墙外保温系统在超高层建筑应用技术研究

自2011年3月15日起,民用建筑外保温材料燃烧性能要求为A级。岩棉板作为无机不燃材料,具有导热系数小、保温性能高、透气性好等优点被广泛应用于外墙外保温建筑工程中。但由于岩棉板密度大,易变形和翘曲,主要在幕墙内使用,其薄抹灰系统在超高层建筑中应用极为少见。结合工程实例,阐述岩棉板薄抹灰系统在超高层建筑外保温中应用所遇到的抗风压、抗剪切、锚栓数量等问题,在理论计算的基础上,分析本系统的技术难点,提出解决办法,通过实体检测和工程验收符合设计要求,为类似工程提供借鉴。     

加气混凝土湿物理性质的测定

分析建筑围护结构的热湿过程有着重要意义,而材料的物理性质是完成分析必不可少的参数。对中国常用多孔建筑材料而言,其湿物理性质并不完备。在20~25℃下,依据ISO和ASTM标准,通过平衡吸放湿实验、压力平板实验、蒸汽渗透实验、毛细吸水实验和真空饱和实验,对中国产B07级加气混凝土进行了测试,得到了包括等温吸放湿曲线、保水曲线、蒸汽渗透系数、液态水扩散系数、吸水系数、毛细饱和含湿量和真空饱和含湿量在内的所有湿物理性质。     

常用保温材料单体燃烧性能浅析

当前用于建筑保温的材料主要有EPS板、XPS板、PU板、酚醛树脂板、脲醛树脂板、胶粉聚苯颗粒保温浆料、膨胀玻化微珠保温砂浆、岩棉板等,这些材料在保温节能方面发挥着至关重要的作用,但同时材料自身的组成成分制约着其燃烧性能的分级。依据GB／T20284—2006《建筑材料或制品的单体燃烧试验》标准进行单体燃烧试验,对不同材料在燃烧过程中的燃烧增长速率指数、热释放量、产烟量及滴落物／微粒产生情况等指标进行比较,旨在为保温材料在保温工程使用中提供防火方面的参考。     

钢管高强混凝土自收缩规律的研究

本文从理论上分析了钢管核心混凝土的变形机理,指出在水化过程中存在收缩变形和膨胀变形两种变形趋势,最终的变形表现为收缩还是膨胀取决于两种变形趋势谁占优势。并通过对7组钢管混凝土构件的变形测定来分析水胶比、外掺料、截面尺寸等因素对核心混凝土自收缩的影响以及钢管混凝土作为一种组合构件自身的一些特点。通过试验发现核心混凝土的自收缩随着水胶比的增大而减小,水胶比大的普通混凝土会表现为膨胀;掺硅粉可增大自收缩,掺粉煤灰可减小自收缩;自收缩值与构件尺寸关系不大。核心混凝土的收缩是在外围钢管约束下的收缩,收缩会使钢管产生压应力,混凝土产生拉应力,由于粘结强度较小,收缩引起的应力达到一定值后会使钢管与混凝土脱离,但一般会保持一定的应力余量,说明钢管与混凝土没有完全脱离。最终混凝土收缩的影响表现为使钢管与混凝土产生初应力,同时使混凝土与钢管有相对位移,纵向的相对位移使核心混凝土上表面低于钢管的上表面。     

Properties of thermal insulation materials during extreme environment changes

In this experimental study properties of condense formation, drainage and moisture dependent heat transmittance were studied for three different thermal insulation materials often used in railway carriages; glass wool (from Isover), melamine foam (Basotect) and corrugated sheets of cellulose plastics (Moniflex). The materials are quite different with respect to condense formation and maximal moisture accumulation at similar environmental conditions. They showed also considerable differences in moistures’ influence on thermal transmissivity. The higher the moisture accumulation, the bigger the moistures’ influence on thermal transmissivity at steady state. At a sudden reversion of the temperature field the moisture gave a temporary effect of even higher heat transmission for 1–2 h.     

岩棉保温屋面应用技术研究

本研究的岩棉保温屋面构造由结构层、隔汽层、岩棉板保温层、找坡层、找平层、防水层、保护层所组成,具有保温层厚度薄且价格低、屋面荷载轻、施工效率高等特点.文中还介绍了对各层的要求及应注意的施工要点.     

基于夏热冬冷地区墙体内保温热湿耦合特性研究

为了研究内保温墙体内部的温度和水蒸气分压力分布,分析出内保温墙体系统内部的结露点。通过建立内保温墙体数学模型,利用解析计算的方法计算出在稳态条件下离心玻璃棉和聚氨酯保温板(PU板)内保温墙体系统内部节点的温湿度,研究了内保温墙体模型内的温度和水蒸气分压力分布曲线;分析出结露点主要发生在保温材料与混凝土砌块界面处;通过实验验证了结论的正确性,且得出离心玻璃棉比PU板更容易结露。为工程设计提供参考依据。     

TPO单层屋面系统在亚新科天纬(天津)项目中的应用

介绍了由聚酯纤维内增强型TPO防水卷材、岩棉保温板、PE膜隔汽层组成的单层屋面防水保温系统在亚新科天纬(天津)项目中的应用,包括屋面系统深化设计、材料与配件选用、抗风设计、细部节点做法等,以供后续类似工程借鉴.     

钢结构建筑保温屋面系统方案设计与选择

建筑物合理选用保温材料是重要的技术指标和经济指标之一,钢结构建筑常用的保温材料有玻璃棉和岩棉两类,本文通过这两类保温材料热工性能的分析,结合其在巴特勒钢结构建筑系统中的典型应用,其中包括适用于不同的气候分区的单层保温棉和双层保温棉两大系统,为钢结构建筑保温屋面系统的设计与选用提供借鉴。     

Transient hygrothermal behaviour of a hemp concrete building envelope

The sustainable world's economic growth and people's life improvement greatly depend on the use of alternative products in the architecture and construction, such as industrial wastes conventionally called green materials. For this purpose, hemp concrete is more and more recommended by the eco-builders because hemp is a renewable plant, recyclable and does not degrade within time. It corresponds perfectly to the requirements of high environmental quality buildings. The objective of this article is to study transient hygrothermal behaviour of hemp concrete at whole building level. The physical model is one-dimensional and was implemented into the object-oriented simulation environment SPARK, using the finite difference technique with an implicit scheme. The numerical result showed that the use of hemp concrete wall in buildings can ensure good indoor air quality and energy savings in winter. Besides, the combined effect of moisture buffering with the adequate ventilation strategies increases hemp concrete building performance. Our results also suggest that taking into account the hygrothermal transfer at whole building level with heat and moisture production sources has significant effects on predictions.     

轨道交通新线车站空调保温材料采用泡沫玻璃的探讨

本文通过对泡沫玻璃与玻璃棉两种保温材料比较分析,结合轨道交通六号线的运用情况,对新线分站供冷车站冷冻水管保温材料采用泡沫玻璃的可行性进行探讨,并提出相关建议。