纤维轻骨料混凝土基本力学性能与保温性能试验研究

发布时间：2018-10-05 06:35

【摘要】：轻骨料混凝土具有质量轻、耐火性能好、抗震性能佳、保温隔热效果好等优点,广泛应用于工民建及其他工程中。但是轻骨料混凝土的脆性比较大,容易发生开裂与脆性破坏,已经限制其在现实工程中的应用。研究发现,在轻骨料混凝土中掺加适量的纤维可以改善其力学性能,能够明显提高轻骨料混凝土的抗拉和抗折性能,阻止裂缝的扩展,改变其破坏形态。通过单掺玄武岩纤维、聚丙烯纤维对各种不同掺量下的纤维轻骨料混凝土试块进行相关力学性能试验、表观密度和保温隔热性能试验研究,最终确定出最佳掺量,并进行节能设计。将玄武岩纤维和聚丙烯纤维两个因素作为参数进行了试验设计,玄武岩纤维掺量为 Okg/m3、1kg/m3、2kg/m3、3kg/m3,聚丙烯纤维掺量为 Okg/m3、0.3kg/m3、0.6kg/m3、0.9kg/m3。其中基本力学性能试验总共设计7组试验,对不同纤维掺量下的轻骨料混凝土进行抗压强度、劈裂抗拉强度、抗折强度对比,在确定最佳掺量为玄武岩纤维掺量3kg/m3后,还进行了轻骨料混凝土的干表观密度试验和保温隔热性能试验。抗压强度试验表明,在单掺玄武岩纤维情况下,玄武岩纤维在掺量为3kg/m3时对轻骨料混凝土的抗压强度增长幅度最大;在单掺聚丙烯纤维时,除了掺量为0.3kg/m3的聚丙烯纤维使得轻骨料混凝土抗压强度增长了 3.3%,其他两种掺量都对轻骨料混凝土的抗压强度有不同程度的降低。在破坏形态方面聚丙烯纤维和玄武岩纤维能够较好的减少试块的裂缝数,使其破坏呈现出塑性破坏状态。劈裂抗拉强度试验表明,无论是掺加玄武岩纤维还是聚丙烯纤维,对于轻骨料混凝土的劈裂抗拉强度都起到了较好的增强作用。单掺玄武岩纤维时,对于轻骨料混凝土的劈裂抗拉强度增强效果均达到了 30%以上,其中在玄武岩纤维掺量为1kg/m3时,轻骨料混凝土劈裂抗拉强度增长率最高为35%,而在掺量为3kg/m3时劈裂抗拉强度也增强了 33.9%。掺加聚丙烯纤维后,对于提高轻骨料混凝土的劈裂抗拉强度有明显的效果,在掺量为0.3kg/m3时对轻骨料混凝土的劈裂抗拉强度增强效果最高,增长率为27%。抗折强度试验表明,玄武岩纤维和聚丙烯纤维的掺入,均能够提高轻骨料混凝土的抗折强度。随着聚丙烯纤维或玄武岩纤维掺量的增加,抗折强度也逐渐增加。比较两种纤维对轻骨料混凝土力学性能的增强效果,发现聚丙烯纤维对其抗压强度、抗折强度提高效果不明显,而玄武岩纤维不仅能够稍微改善轻骨料混凝土的抗压强度,而且能够明显改善其劈裂抗拉性能和抗折性能,最终确定玄武岩纤维在掺量为3kg/m3时为最佳纤维掺量。在节能设计中,纤维轻骨料混凝土墙板的节能效果能够满足规范要求。
[Abstract]:Lightweight aggregate concrete is widely used in civil engineering and other projects because of its advantages of light weight, good fire resistance, good seismic performance and good thermal insulation effect. However, lightweight aggregate concrete is more brittle and prone to cracking and brittle failure, which has restricted its application in practical engineering. It is found that adding appropriate amount of fiber to lightweight aggregate concrete can improve its mechanical properties, improve the tensile and flexural properties of lightweight aggregate concrete, prevent the crack from spreading and change its failure pattern. Through the experiments of mechanical properties, apparent density and heat insulation properties of fiber lightweight aggregate concrete samples with different contents of single doped basalt fiber and polypropylene fiber, the optimum content was finally determined. And carry on the energy saving design. Two factors, basalt fiber and polypropylene fiber, were used as parameters in the experiment design. The content of basalt fiber was Okg/m3,1kg/m3,2kg/m3,3kg/m3, polypropylene fiber and the content of polypropylene fiber was Okg/m3,0.3kg/m3,0.6kg/m3,0.9kg/m3.. Among them, 7 groups of basic mechanical property tests were designed. The compressive strength, splitting tensile strength and flexural strength of lightweight aggregate concrete with different fiber content were compared. After determining the optimum addition amount of basalt fiber 3kg/m3, The dry apparent density test and thermal insulation test of lightweight aggregate concrete were also carried out. The results of compressive strength test show that the compressive strength of lightweight aggregate concrete increases greatly when basalt fiber is doped with 3kg/m3, and when polypropylene fiber is added alone, the compressive strength of lightweight aggregate concrete increases greatly when the content of basalt fiber is 3kg/m3. The compressive strength of lightweight aggregate concrete is increased by 3.3% due to the addition of polypropylene fiber (0.3kg/m3), and the other two kinds of fiber have different degree of decrease on the compressive strength of lightweight aggregate concrete. Polypropylene fiber and basalt fiber can reduce the number of cracks in the specimen and show plastic failure state. The splitting tensile strength tests show that both basalt fiber and polypropylene fiber can enhance the splitting tensile strength of lightweight aggregate concrete. When basalt fiber is added alone, the splitting tensile strength of lightweight aggregate concrete can be enhanced by more than 30%, especially when the content of basalt fiber is 1kg/m3, The maximum growth rate of splitting tensile strength of lightweight aggregate concrete is 35%, while the splitting tensile strength of lightweight aggregate concrete increases by 33.9 when the content of 3kg/m3 is added. The effect of adding polypropylene fiber on the splitting tensile strength of lightweight aggregate concrete is obvious. When the content of 0.3kg/m3 is added, the effect of strengthening the splitting tensile strength of lightweight aggregate concrete is the highest, and the growth rate is 27%. The flexural strength tests show that the addition of basalt fiber and polypropylene fiber can improve the flexural strength of lightweight aggregate concrete. With the increase of polypropylene fiber or basalt fiber content, the flexural strength increases gradually. Comparing the mechanical properties of lightweight aggregate concrete with two kinds of fibers, it is found that polypropylene fiber can not improve the compressive strength and flexural strength of lightweight aggregate concrete, but basalt fiber can not only improve the compressive strength of lightweight aggregate concrete, but also improve the compressive strength of lightweight aggregate concrete. Moreover, the splitting tensile and flexural properties of basalt fiber can be improved obviously. Finally, the optimum content of basalt fiber is determined when the content of basalt fiber is 3kg/m3. In the energy-saving design, the energy-saving effect of fiber-light aggregate concrete wallboard can meet the requirements of specifications.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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