【作者】 王海龙；

【导师】 申向东；

【作者基本信息】 内蒙古农业大学 ， 农业水工建筑物， 2009， 博士

【摘要】 本文通过对浮石性能的研究,针对轻骨料混凝土强度变异性大的特点,配制三种强度等级(LC30,LC25,LC20)的轻骨料混凝土并作了早期性能研究,针对粉煤灰、纤维等做了抗冻耐久性等的研究,研制适用于北方寒冷地区水工建筑物的使用的轻骨料混凝土。轻骨料混凝土早期强度发育较普通混凝土迟,随龄期增加,脆性能力平稳增强,在28天龄期受压破坏时,浮石骨料被完全剪切破坏;早期轻骨料混凝土弹性模量随龄期增长关系都较普通混凝土小,表现出塑性性能;轻骨料混凝土28天全应力应变曲线形式与普通混凝土基本类似,但变形区间较大;利用分段应力应变曲线方程对LC30混凝土在28天的拟合中,拟合结果较好。针对北方地区的资源情况和浮石骨料的表面特征,研究了粉不同煤灰掺量的耐久性能,考虑了寒区水工建筑物环境特点,耐久性设计了碳化性能、抗渗性能、氯离子侵蚀性能等方面的试验;得出粉煤灰掺入对轻骨料混凝土抗渗性能影响最优的为25%-32%之间;粉煤灰掺量对轻骨料混凝土碳化程度影响与粉煤灰掺量呈现正比关系;30%以内的粉煤灰掺量能保证轻骨料混凝土后期强度发育较高。本文进行了轻骨料混凝土、纤维混凝土和碎石轻骨料混凝土的立方体抗压强度、轴心抗压强度、抗折强度和弹性模量、受压破坏等试验,对比聚丙烯纤维和碎石对轻骨料混凝土的增强或增韧效果;以及对纤维增强轻骨料混凝土与碎石轻骨料混凝土的破坏形式进行对比,纤维破坏形式主要表现为横向受剪,碎石轻骨料混凝土破坏时骨料出现松动。抗冻耐久性试验中以LC30为基准轻骨料混凝土,在掺入纤维后能大幅度提高轻骨料混凝土的抗冻性能。碎石取代部分轻骨料后,轻骨料混凝土强度虽有一定的提高,抗冻性能却下降较大。纤维轻骨料混凝土在冻融后损伤情况进行研究:以损伤度作为研究对象,得出的轻骨料混凝土耐久性性能在纤维掺量为0.9kg/m3时,抗冻性能较好。利用多项式拟合纤维轻骨料混凝土碎冻融次数与损伤度变化的关系,拟合关系较好。在模拟室外环境条件下对纤维轻骨料混凝土进行三温冻融循环试验发现,冻融次数的增加,温度传导更加顺畅,协调变形能力增强,与标准冻融循环相比强度与质量损失在相同冻融次数下较小,纤维掺量为0.9kg/m3时冻胀应力较小,协调变形能力最好,75次冻胀量发育为2mm左右。更多还原

【Abstract】 2In this paper, pumice lightweight aggregate concrete (LWAC) of LC20,LC25 and LC30, which are specially suitable for being used in cold region, are compounded with the method of mixing fibers, high-quality air-entraining agent and mineral admixtures. In view of the environmental features of cold region,Lightweight aggregate concrete early strength development later than normal, with a view to increasing age, the capacity of a smooth enhancing brittle, in the age of 28 days compressive damage, the pumice aggregate were completely shear failure; lightweight aggregate concrete with early modulus of elasticity growth are small compared with ordinary concrete, the plastic properties of performance; lightweight aggregate concrete stress-strain curves of concrete forms and general similar, but larger deformation range; the use of sub-equation of stress-strain curves of concrete in 28 of LC30 days of fitting in better fitting results.Resources for the northern region and the surface characteristics of pumice ,studing the different ash content of flour durability, cold regions taking into account the environmental characteristics of hydraulic structures, the durability design of the carbonation performance, impermeability, chlorine properties of ion erosion of the test; come incorporation of fly ash lightweight aggregate concrete impermeability properties for the best between 25% -32%; fly ash lightweight aggregate concrete carbonation on the degree of influence and a positive correlation between fly ash; 30% less than the fly ash lightweight aggregate concrete guarantee that the late development of higher strength.In this paper, a lightweight aggregate concrete, fiber reinforced concrete and lightweight aggregate concrete rubble of the cube compressive strength, axial compressive strength, flexural strength and modulus of elasticity, compression damage test, comparison of polypropylene fiber and gravel lightweight aggregate concrete for enhanced or toughening effect; as well as fiber-reinforced lightweight aggregate concrete and lightweight aggregate concrete rubble of the destruction of the form of contrast, fiber damage is mainly expressed in the form of transverse shear, damage to lightweight aggregate concrete rubble occur when loose aggregate.In this paper, based on LC30 lightweight aggregate concrete, in the introduction of fiber can significantly improve the lightweight aggregate concrete properties of the antifreeze. Gravel to replace the part after the lightweight aggregate, lightweight aggregate concrete strength despite some improvement in performance has declined more antifreeze. Fiber lightweight aggregate concrete after freeze-thaw damage in the study to investigate the degree of injury for the study, drawn from the performance of lightweight aggregate concrete durability in the fiber content for 0.9kg/m3, the antifreeze properties. The use of polynomial fitting broken fiber lightweight aggregate concrete and the number of freeze-thaw damage the relationship between the degree of change, a better fitting relations. In a simulated environment under the condition of outdoor fiber lightweight aggregate concrete freeze-thaw cycle three temperature test found that increase in the number of freeze-thaw, temperature conduction more smooth, enhancing the capacity of co-deformation, compared with the standard freeze-thaw cycles and the mass loss of strength in the same the smaller the number of freeze-thaw, when the fiber content for 0.9kg/m3 less frost heave stress, deformation capacity to coordinate the best, 75 times the volume of development of frost heave for about 2mm.更多还原