Untersuchung der thermisch‐hygrischen Eigenschaften von Ziegeln mit Hohlraumfüllung aus Recyclingmaterial

Investigation on the thermal‐hygral behaniour of bricks with canity filling by recycling meterials. In the investigation project was examined whether bricks with simple cavity structure have a higher heat resistance by use of a heat insulation material filling in the cavities. The insulation material is a recycled product made of polystyrene and wood covered and bonded with cement. The influence of the configuration and thickness of the perforated bricks with vertical perforations and the geometry of the cavities of the brick on the thermal moisture states was evaluated. For investigation of the thermal resistance and the heat transmission coefficients were used the simulation program THERM, that considered the heat transportation through conduction in the brick fragments and the transport mechanisms conduction, convection and radiation in the airfilled cavities. The software package WUFI 2D was employed for the investigation of moisture transfer in the bricks. The investigations showed that the composite brick insulation stone has a thermal resistance twice as high as the initial brick. The moisture states can be partially in the brick more than 80 % humidity. This load is estimated as uncritical because the wooden particles are covered with cement slime.     

Analysis of coupled natural convection–conduction effects on the heat transport through hollow building blocks

In the present study, the coupled convective and conduction heat transport mode in a common hollow building brick is studied. Heat transfer rate through building bricks is examined in order to asses the suitable brick insulation configuration. Three different configurations for building bricks are considered. The first is a typical brick of three identical hollow cells (air cavities), the second is obtained by filling these cells with ordinary polystyrene bars and the third is obtained by using hollow polystyrene bars. The geometry of the first and third configurations considered in this study is simply a solid closed frame surrounding square cavities filled with air. The second configuration is a solid composite slab. Solving Navier–Stocks equations assuming Boussinesq approximation, using the commercial Fluent software, showed that the cellular air motion inside blocks’ cavities contributes significantly to the heat loads. Insertion of polystyrene bars reduced the heat rate by a maximum of 36%. Using a hollow polystyrene bars reduces the heat rate by 6% only due to the air motion inside cells. In order to estimate the heat rate during a day, the air temperature and solar insolation data of a typical summer day for the city of Jeddah, Saudi Arab, are used. A quazi-steady state approach is implemented to estimate an equivalent facade surface temperature, which is then used as boundary for solving the simulation model. Such an approach showed that the effective overall daily heat rate reduction using polystyrene filled bricks to be 25%.     

节能型烧结空心砖自保温墙体的适应性研究

文章分析了在黄土资源丰富的寒冷地区发展节能型烧结空心砖自保温墙体的优势,通过对墙体热工参数的计算,得出节能型烧结空心砖自保温墙体可以满足国家节能50％的要求,甚至在有些地区只要控制好建筑的体形系数,可以达到节能65％。     

夹心保温砌体房屋振动台试验研究

黏土砖是我国北方地区广泛使用的主要建筑材料。通过水平灰缝和竖向灰缝连接成整体砖墙,承受竖向荷载和水平荷载。传统的砌体墙热工性能差,在我国最寒冷的地区其厚度可达半米,过大的厚度,一方面使建筑自重过大,抗震能力较差,另一方面也占用较大的居住面积。为解决这一矛盾,文中研究的夹心保温砌体砖墙黏土夹层砖墙是通过在钢筋网连接的两层较薄的砖墙之间插入隔热层,形成夹心保温砌体房屋。为研究其抗震性能,对一个1/2比例的4层黏土夹层砖墙结构进行不同地震烈度下的振动台试验,对其抗震性能进行试验评估,包括动力特性和响应、破坏模式、荷载和变形能力以及损伤演化等。试验结果表明：由于水平拉结钢筋网和构造柱的约束,外墙、保温层和内墙能较好地协同工作;黏土夹芯砖墙结构能满足我国《建筑抗震设计规范》(GB 50011—2010)规定的7度抗震设防的要求。     

Internal baffles to reduce the natural convection in the voids of hollow blocks

Hollow bricks are widely used to build facades of light weight and high thermal resistance. The air filled voids within the brick configuration elevates the block’s thermal resistance. Disturbing the natural flow patterns developed inside the voids affects the blocks overall thermal resistance. This paper presents a numerical study for a section of a masonry brick represented by a baffled squared cavity surrounded by a conductive wall of finite thickness. The baffles are attached to the top and bottom sides dividing the void into three regions. The thermal resistance of the partitioned voids depends on baffles length and location. Short baffle develops a stratified region in the central gap and generates two circulation zones near the upper left and lower right corners. Long baffles, on the other hand, splits the flow into three different convection circulation cells, a cell near each side of the cavity and a third in the central gap. Increasing the baffle height increases the thermal resistance of the partitioned cavity for all gap widths. The highest increase in thermal resistance is 53% over the non baffled voids and is achieved with long baffles when located to divide the cavity into three regions of equal widths.     

Heat conduction across double brick walls via BEM

The Boundary Element Method (BEM) is used to compare the steady-state heat and moisture diffusion behaviour across double brick walls provided by two different models: in the first one, the brick wall is assumed to be composed of a set of homogeneous layers bonded together, which is the model frequently used to predict internal condensation; in the second model, the geometrical modelling and hygrothermal properties of the individual bricks are taken into account.The BEM is implemented allowing the use of multi boundaries, which permits the full discretization of the brick cavities.Three different construction solutions are analysed. In the first, the double-brick wall is assumed not to be thermally insulated; in the second, the space between the two layers of bricks is filled with thermal insulation material; in the third solution, both the space between the brick layers and the holes of the inner brick layer are filled with thermal insulating material.     

新型外墙保温系统研究

通过对比新型外墙保温系统与普通粘土砖墙及经典外保温系统胶粉聚苯颗粒系统,利用ANSYS软件计算了热应力、变形和温度分布等物理量。计算结果表明,在相同厚度下,几种保温系统均满足强度要求,胶粉聚苯颗粒系统的保温性能优于普通粘土砖墙。     

河道於泥自保温烧结多孔砖的性能研究

研究了河道淤泥自保温烧结多孔砖的原料配比与生产工艺,及其外观性能、物理力学性能、热工性能和环境安全性。结果表明,河道淤泥自保温烧结多孔砖强度等级达到Mul0以上,其各项指标均达到或超过相应的国家标准规定要求。对其砌筑的240mm厚度墙体,采用普通砂浆与20mm无机保温砂浆抹面,其墙体体系热阻分别No．883,0．974m2·K／W,分别满足《夏热冬冷地区居住建筑节能设计标准》中节能率50％-~565％的要求。     

空心砖与空心砖节能建筑

根据多年来对空心砖及空心砖节能建筑研究与推广的实践经验，阐述了各种空心砖的规格性能及确定其外形尺寸和孔型的依据，介绍了节能５０％空心砖建筑试点工程。提出１６种节能５０％空心砖建筑墙体方案供设计参考。     

Sustainable earth walls to meet the building regulations

The thermal conductivity and diffusivity of un-fired clay bricks, a straw clay mixture and straw bales have been measured using a thermal probe technique, with an iterative method for data analysis. The steady-state air-to-air thermal transmittance, or U-value, and the time-dependent thermal properties of some proposed sustainable earth wall constructions are presented. Sustainable cavity walls of un-fired clay bricks with paper, straw or wool cavity insulation have thermal transmittances less than 0.35 W/m² K, and therefore meet the current United Kingdom Building Regulations. A review of possible methods for thermally up-grading existing earth walls, by adding an internal insulated timber frame construction, again demonstrates possible compliance with the current UK thermal regulations.     

Numerical simulation by the FVM of coupled heat transfers by conduction, natural convection and radiation in honeycomb’s hollow bricks

This paper presents a detailed numerical study, in steady state regime, of the interaction between two dimensional heat transfers by conduction, natural convection and radiation in double hollow bricks formed by two honeycomb walls separated by an air layer. The air motion in all cavities of the system is laminar. The left and right vertical sides of the hollow bricks are considered isothermal and maintained at different constant temperatures. The top and bottom horizontal sides are assumed to be adiabatic. The governing equations are solved using the finite volume method (FVM) and the SIMPLE algorithm. The impact of the thickness of the air layer on the global heat flux through the structure is discussed. The simulation results show that the variation of the overall heat flux through each hollow brick as a function of the temperature difference ΔT between the vertical sides of the system is almost linear for the different types of double hollow bricks considered. This linear thermal behaviour allowed the generation of appropriate overall heat exchange coefficients that permit fast and accurate prediction of heat transfers through the hollow bricks without solving the complex system of equations governing the coupled heat transfers. Comparison of the performance of different types of double hollow bricks is made.     

The behaviour of masonry walls subjected to fire: Modelling and parametrical studies in the case of hollow burnt-clay bricks

A thermo-mechanical model is adopted in order to investigate the fire behaviour of clay masonry walls. In this analysis, conductive, convective and radiative thermal transfers are considered together with local energy consumption due to phase changes. These latter are essentially initiated by both the vaporisation of adsorbed water and the chemical transformation of clay under rising temperatures. Therefore, experimental tests at both the material scale and the brick scale are performed in order to identify the parameters that characterise the thermo-hygral behaviour of clay. For this purpose, numerical simulations are carried out on the experimentally tested hollow bricks in order to determine by back analysis these material parameters. The thermal model being validated, the thermo-mechanical behaviour of a masonry wall subjected to fire, is thereafter investigated by adopting a full three-dimensional finite-element analysis. Numerical simulations results are compared to the experimentally measured ones in terms of both temperature and out-of plane displacement fields. In this analysis, it is shown that a non-linear elastic behaviour for bricks and mortar with temperature-dependent mechanical parameters is sufficient to retrieve the overall behaviour of thin masonry walls. Finally, a parametric study provides the influence of each material parameter on the fire behaviour of the partition walls.     

无机复合烧结页岩空心砖的研制

以热工性能为导向,研制了一种无机复合烧结页岩空心砖。将5排12孔洞砖改为6排13孔,增加1个单填充孔,且于单填充孔内灌注自制保温填料,所得无机复合烧结页岩空心砖具有良好的热工性能、力学性能及隔声性能。保温填料配比中约掺1/3的粉煤灰,增加了其环境效益。此外,灌装工艺的突破极大提升了该产品的规模化、工业化生产能力和推广价值。     

节能型烧结空心砖(砌块)强度检测与砌筑的探讨

为降低烧结砖墙体的"使用耗能",烧结空心砖采用薄壁多孔洞单向错位排列结构设计。比对试验证明,单向错位排列的孔洞结构导致烧结空心砖的不同受压面的抗压强度相差悬殊。因此,烧结空心砖必须按产品说明书规定的砌筑面施工和检测。节能型烧结空心砖(砌块)是烧结空心砖(砌块)的一种,也属于"烧结保温砖和烧结保温砌块"。目前尚无国家、行业、地方"节能型烧结空心砖和空心砌块"专用标准,该文建议将《烧结保温砖和保温砌块》(GB26538-2011)作为"节能型烧结空心砖"产品标准执行。砖厂应在产品说明书中标明"砌筑面"及强度等级,施工必须按规定面砌筑。     

我国建筑节能的发展

在我国,三步节能是建筑节能的目标。第一步节能约30％,第二步总节能约50％。第三步总节能约65％。第一步节能采用粘土空心砖墙体、加气混凝土墙体、内保温技术;第二步节能采用膨胀聚苯乙烯板加薄层抹灰并用玻璃纤维加强,以挤塑聚苯乙烯做外保温材料,以单面钢丝网架聚苯板做外墙外保温,或将保温膏料用于外墙外保温;第三步节能可将保温材料加厚,发展其他新型材料和保温材料,控制传热系数,采用聚氨酯硬泡喷涂外墙保温等,建筑遮阳隔热、建筑环境绿化降温、太阳能和地热利用等技术也是我国建筑三步节能应进一步研究、开发的方向和领域。     

泡沫混凝土外墙的热工性能测试与分析

随着建筑能耗的不断增加以及能源危机的日益加剧,建筑节能变得尤为迫切。外墙是围护结构节能的重点。泡沫混凝土因良好的保温隔热性能被广泛应用于建筑工程中,但其在建筑外墙的应用还处于探索阶段。本文介绍了新型泡沫混凝土外墙的构造及性能特点,并通过实验对比分析了外保温墙体、实心砖墙体和泡沫混凝土墙体的保温隔热性能。实验结果显示,泡沫混凝土外墙的保温隔热性能远优于其他两种墙体,在空调状态下,其内表面的热流值仅为外保温墙体的30.4%,具有显著的节能效果。不仅如此,泡沫混凝土外墙更为轻质,其质量仅为外保温墙体的49.1%。     

燃气爆炸对砖混住宅安全影响分析

随着燃气应用的普及,住宅燃气爆炸事故时有发生,文章通过某住宅楼发生燃气爆炸后的现状调查,分析了燃气爆炸的特点及对砖混结构住宅安全的影响,并提出了减少爆炸影响的防护措施,探索性提出燃气爆炸下一步研究的重点。     

The effects of temperature conditions on the thermal resistance of walls made with different shapes vertical hollow bricks

The authors used a testing program in order to determine the thermal resistance of terra-cotta walls; built with vertical hollow bricks. These bricks could be standard ones, so cavities were 25 cm high, or they could reach 250 cm (story-height bricks). Different hollow shapes were tested under different boundary conditions on temperature. The authors tried to determine for this class of bricks used in France, the most performing outline, from a thermal point of view, under different boundary conditions.     

模数多孔砖砌块砖的块型设计

建筑围护结构的传热阻是提高保温性能、降低采暖能耗的主要考量,对墙体砌块的设计及其砌筑时的工艺已成为保障提高建筑围护结构传热阻的关键。其中,模数多孔砌块砖型被列为国家节能墙体新材料行列,已成为住宅建筑围护结构的主要部品。     

Sound insulation of fibre reinforced mud brick walls

The aim of this paper is to find a better alternative for the insulation of industrial noise and to improve the mechanical properties of fibre reinforced mud bricks. It was observed that the fibre reinforced mud bricks fulfill the compressive strength and sound insulation requirements of the ASTM and Turkish Standards. Basaltic pumice as an ingredient was found to improve the sound insulation performance of fibre reinforced mud bricks. The experimental results showed that fibre reinforced mud brick, with basaltic pumice as ingredient, can be used in industrial buildings for walls to improve sound insulation.