承重保温夹芯无拉接件的复合墙体的研究

发布时间：2018-01-31 08:47

本文关键词： 承重保温夹芯复合墙体引气型全轻轻集料混凝土泡沫混凝土墙体力学有限元分析无拉接件设计热工性能生产工艺设计　出处：《华南理工大学》2013年博士论文　论文类型：学位论文

【摘要】：随着我国建筑节能工作不断深入和完善，特别是建筑节能设计标准体系的建立，对外墙的传热系数和热惰性指数有了明确的要求。但在所有的新型墙体材料中，只有加气混凝土是良好的节能材料，却存在着强度低、收缩较大、抗渗透能力较差等问题。研究开发使用保温隔热效果好、使用方便、又能作为外墙承重、各项技术性能都优秀的实用型新型墙体材料是建筑节能的迫切需要。保温夹芯复合墙体既具有外保温墙体的一些共性特点，又具有保护保温材料、保护主体结构、改善墙体潮湿情况、改善室内热环境质量等特点，适用于既有承重要求，又对保温性能有要求的墙体结构，具有巨大的技术经济优势和非常广阔的市场前景，是建筑节能研究的热点之一。但是，目前保温夹芯复合墙体在材料选型、结构设计、产品开发等环节上主要依赖实际经验和既有生产工艺。研究开发存在以下两点突出问题。其一、结构层主要采用普通混凝土或轻质混凝土，大都布置了纵向钢筋网和横向钢筋拉接件，这一方面大大增加墙体自重，使结构趋于复杂化，又极不利于降低导热系数，减少热阻和热桥效应。以往的研究已经指出，横向拉接件在外荷载中承受的应力很小；且拉接件的间距和类型对于夹芯墙的抗压强度和弹性模量影响都很小。其二、现有的夹芯复合墙板的保温层均采用有机材料，导致夹芯复合墙板存在着内部容易结露，防火性能差等缺点，教训良多。因此，本论文在综合分析了各种复合墙体研究的基础上，确定以引气型全轻轻集料混凝土为结构层材料、加气泡沫混凝土为保温层材料的基本组成单元，对承重保温夹芯复合墙体进行理论的力学模拟及实验的材料制备与结构设计的研究。本文首先针对我国夏热冬暖地区居住建筑节能的要求，选定以陶粒混凝土为结构层和泡沫混凝土为保温层的直板板式复合结构，利用有限元分析法对无拉接件的承重保温夹芯复合墙体进行了力学的模拟研究，提出了普遍适用的这种类型墙体在竖向荷载和风荷载作用下各种应力分布的基本规律。发现了竖向压应力主要由结构层承担，底部两角压应力明显较大，墙高的两侧的中下位置，存在着压应力相对较小的区域，竖向荷载作用下，夹芯界面上的切向接触应力很小，风荷载作用下，墙体界面法向应力峰值出现在墙高约1/4和3/4的位置，随着墙厚及墙高度增加而增大等。证明了无拉接件的承重墙体是可能实现的。获得各种宽高比下的力学性能数据。其中，墙体总厚度150mm，保温层厚度40mm，承重10MPa下的保温夹芯复合大型墙体，有限元分析要求结构层抗压强度大于13.6MPa，保温层抗压强度大于0.19MPa，，结构层与保温层界面间的剪切强度应大于3.89KN/m~2，粘结强度必须大于1.45KN/m~2。为了配制既能承重又兼具一定隔热功能、用于保温夹芯复合墙体的结构层的全轻轻集料混凝土，本文采用引气技术，研制得容重为1110kg/m3，28天抗压强度为18.8MPa，导热系数为0.38W/(m·K)的引气型全轻轻集料陶粒混凝土。系统研究了聚羧酸引气剂、松香酸钠引气剂、月桂基引气剂对全轻轻集料混凝土容重、孔隙率、孔分布及吸水率等的影响，发现聚羧酸和月桂基的引气效果优于松香酸钠。发现了单一引气剂的引气效果优于复合引气。提出了在全轻轻集料混凝土添加月桂基引气剂，可制备出高强、轻质、导热系数小的全轻轻集料混凝土。本文继而研究了水胶比、粉煤灰掺量、发泡剂种类和用量对泡沫混凝土性能的影响，选用了动物蛋白型发泡剂，制备出容重为620kg/m3、抗压强度为1.9MPa、导热系数为0.18W/(m·K)的泡沫混凝土。在此基础上，本文首次研究开发了结构层和保温层均为水泥基无机材料、无拉接件的满足夏热冬暖地区居住建筑节能的要求的承重保温夹芯复合墙体结构。为了克服结构层和保温层界面粘结力不足的缺陷，系统研究了不同齿形嵌合方式对墙体力学性能的影响，发现合理的界面齿形嵌合的方法可以大幅度增加界面的劈裂抗拉强度，同时也增加抗压强度，从而使无拉接件的设计思想成为可能。该种复合墙体的热工性能测定和计算表明，该复合墙体的设计不仅可以满足夏热冬暖地区承重外墙的节能要求，而且因无拉接件而克服了这类型墙体的冷热桥效应的通病和以及采用有机保温材料作为保温层的易燃，耐久性差等缺点。以全轻轻集料陶粒混凝土为结构层材料、水泥泡沫混凝土为保温层材料，采用齿型结构复合方式，齿宽为50-60mm，齿间距为150mm,保温层厚度为40-50mm，研制出墙体厚度为150mm的保温夹芯复合墙体；其劈裂抗拉强度较高，可达1.2MPa，比较直板型复合结构提高了52.4%。其传热系数k约为1.3W/（m~2·K），热惰性指标D约为4.15，完全满足夏热冬暖地区居住建筑节能50%对外墙的热工设计要求。本文还对这种新型复合墙体的生产工艺进行了初步设计。
[Abstract]:With the deepening and improvement of building energy - saving work in our country , especially the building of energy - saving design standard system , there is a clear demand for heat transfer coefficient and thermal inertia index of exterior wall . However , the existing thermal insulation sandwich composite wall mainly depends on the actual experience and the existing production process in material selection , structural design , product development and so on . Firstly , the structure layer mainly adopts ordinary concrete or lightweight concrete , which greatly increases the dead weight of the wall body , makes the structure tend to be complicated , and has very little influence on the compressive strength and the elastic modulus of the sandwich wall . Therefore , on the basis of comprehensive analysis of various composite wall studies , it is determined that the air - induced full - light aggregate concrete is the structural layer material , the aerated foam concrete is the basic component unit of the heat - insulating layer material , and the research on the theoretical mechanics simulation and the material preparation and structural design of the load - bearing heat - insulating sandwich composite wall is carried out . In this paper , according to the requirement of building energy saving in summer and winter warm areas in China , the composite structure of straight plate with ceramsite concrete as structural layer and foam concrete is selected . The mechanical properties data of this kind of wall under the action of vertical load and wind load are discussed . The compressive stress of the wall is more than 13.6MPa , the compressive strength of the thermal insulation layer is greater than 0.19MPa , and the shear strength between the structural layer and the thermal insulation layer should be greater than 3.89KN / m ~ 2 , and the bonding strength must be greater than 1.45KN / m ~ 2 . In order to prepare the full - light aggregate concrete which can bear both load bearing and heat insulation function and is used for thermal insulation sandwich composite wall , this paper studies the influence of air entraining agent , sodium rosin entraining agent and lauryl air entraining agent on the weight , porosity , pore distribution and water absorption of lightweight aggregate concrete . It is found that the air entraining effect of polycarboxylic acid and lauryl group is better than that of sodium rosin . It is found that the air entraining effect of polycarboxylic acid and lauryl group is better than that of compound bleed air . In this paper , the influence of cement ratio , fly ash content , type and dosage of foaming agent on the properties of foam concrete is studied . Animal protein type foaming agent is selected to prepare foam concrete with weight of 620 kg / m3 , compressive strength of 1.9 MPa and thermal conductivity of 0.18 W / ( m 路 K ) . In order to overcome the defects of structural layer and thermal insulation layer , this paper studied the influence of different tooth form fitting methods on the mechanical properties of wall . This paper also makes a preliminary design for the production process of the novel composite wall .

【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU551

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