东北寒区复合自保温混凝土砌块砌体基本力学性能试验研究

发布时间：2018-11-08 07:36

【摘要】：东北寒区对建筑围护结构的力学性能和热工性能都有严格的要求,据调查,寒区常用490mm厚实心粘土砖墙,传热系数高达1.25W/(m2·K)。本文拟研发一种节能效果好、自重轻、墙厚薄、强度高的自保温砌块。本文在课题原有研究成果的基础上,结合振动加压成型陶粒混凝土抗压强度的正交试验结论,提出了对原混凝土空心砌块的配合比进行调整,添加岩棉和炉渣,研发出了墙厚仅为280mm、传热系数分别为031W/(m2·K)和0.39W/(m2·K)的MU3.5和MU5.0高热阻自保温砌块,既满足现行规范的建筑节能要求,又极大地降低了墙厚,节约了材料,增大了使用面积。通过砌块力学性能试验,探究振动加压成型工艺以及陶粒轻骨料成分对新型复合自保温混凝土砌块强度发展的影响。结合已有研究,利用Matlab拟合得到砌块抗压强度随龄期发展的关系式；通过热箱法检测三组砌块墙体的热工性能,探究含水率对砌块墙体热工性能的影响,结合热箱法特点建议砌块墙体热工性能检测时需要严格控制含水率。结合规范要求与实际应用,通过对四组新型复合自保温混凝土砌块砌体的轴心抗压试验,研究砌体受压破坏特征及受压性能(开裂系数和强度利用系数)。探究新型砌块与砂浆的匹配问题,发现砌体规范建议中的“一般砌块强度等级高于砂浆强度等级”不适用于新型自保温复合混凝土砌块。通过理论分析,建议对于空心砌块,砂浆适配强度应高于砌块抗压强度,但略低于砌块混凝土母材强度。分析试验结果,发现新型砌块砌体抗压强度设计值均高于“双排孔或多排孔轻集料混凝土砌块砌体MU5.0+Mb5.0等级”的强度,可用于东北寒区村镇建筑两层砌体结构承重墙。同时,规范提供的混凝土砌块砌体抗压强度平均值同样适用于新型复合自保温混凝土砌块砌体。本文还给出了适用于新型砌块砌体的受压应力—应变曲线建议公式、弹性模量、泊松比的建议取值。对四组新型复合自保温混凝土砌块砌体标准纯剪试件进行沿通缝抗剪性能试验,由于孔洞内插EPS保温板,新型砌块基本实现盲孔铺浆,有效避免砌筑漏浆,新型砌块砌体沿通缝截面抗剪强度相比普通混凝土空心砌块的抗剪强度规范值有大幅提高。
[Abstract]:There are strict requirements for mechanical and thermal properties of building enclosure in northeast cold region. According to investigation, 490mm thick solid clay brick wall is commonly used in cold region, and the heat transfer coefficient is as high as 1.25W/ (m2 K). This paper intends to develop a self-insulating block with good energy-saving effect, light weight, thin wall and high strength. On the basis of the original research results and the orthogonal test results of the compressive strength of the vibration-pressurized ceramsite concrete, this paper puts forward the adjustment of the mix ratio of the original concrete hollow block and the addition of rock wool and slag. The wall thickness is only 280 mm and the heat transfer coefficient is 031W/ (M 2 K) and 0.39W/ (m 2 K), respectively. The MU3.5 and MU5.0 high thermal resistance self-insulating blocks are developed, which not only meet the requirements of building energy saving in current codes, but also greatly reduce the wall thickness. The material is saved and the use area is increased. Through the test of mechanical properties of the block, the influence of vibratory compression molding technology and the composition of ceramic lightweight aggregate on the strength development of the new composite self-insulating concrete block was investigated. Combined with the existing research, the relationship between the compressive strength and the age of block is obtained by Matlab fitting. The thermal performance of three groups of block wall is tested by hot box method, and the influence of moisture content on the thermal performance of block wall is explored. The moisture content of block wall should be strictly controlled when it is suggested by hot box Fatt point to test the thermal performance of block wall. Combined with the requirements of the code and practical application, the compressive failure characteristics and compressive properties (cracking coefficient and strength utilization coefficient) of four groups of new composite self-insulating concrete block masonry are studied through axial compression tests. In this paper, it is found that the "general block strength grade is higher than mortar strength grade" as suggested in masonry code is not suitable for new self-insulating composite concrete block. Through theoretical analysis, it is suggested that the mortar fit strength should be higher than the compressive strength of the block for hollow block, but slightly lower than the strength of the base material of block concrete. It is found that the design value of compressive strength of new type block masonry is higher than that of MU5.0 Mb5.0 grade of double-row hole or multi-row hole lightweight aggregate concrete block masonry, and can be used in the load-bearing wall of two-story masonry structure of village and town building in northeast cold area. At the same time, the average compressive strength of concrete block masonry provided by the code is also suitable for the new composite self-insulating concrete block masonry. This paper also gives the suggested formula of stress-strain curve, elastic modulus and Poisson's ratio for new block masonry. Four groups of standard pure shear specimens of new composite self-insulating concrete block masonry were tested on shearing performance along the pass joint. Due to the EPS insulation board inserted in the hole, the new type block basically realized the slurry laying with blind hole, which effectively avoided the masonry leakage. The shear strength of the new block masonry is much higher than that of the normal concrete hollow block.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU522.3

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