大流动度路面混凝土耐久性试验研究

发布时间：2018-04-09 17:27

本文选题：大流动度混凝土　切入点：正交设计　出处：《重庆交通大学》2015年硕士论文

【摘要】：随着交通量的不断增加以及超载现象的日益突显,要求路面混凝土具有更高的强度和耐久性。大流动度路面混凝土拌合物的坍落度在160mm以上,具有50cm~60cm的坍落扩展度,施工和易性良好、易填充密实,能够有效提高施工进度、保证工程质量、降低环境污染,凝结硬化后又有优异的力学性能和耐久性。本文主要通过室内试验进行大流动度路面混凝土的耐久性研究。首先从影响混凝土耐久性的原材料出发,按规范要求进行原材料各项技术指标的试验,并进行集料的级配设计;进而根据大流动度路面混凝土的设计要求,在配合比参数计算的基础上,选择四因素四水平的正交试验表安排试验,获得不同参数组合下混凝土的工作性和力学性能;根据正交试验的结果,采用极差分析法分析不同试验因素对大流动度路面混凝土工作性及力学性能影响的显著性,从正交试验表中优选较优的组合,并剔除不符合大流动度路面混凝土设计要求(坍落度160mm以上、抗折强度5.0MPa以上、抗压强度为C30)的组合;在较优组合的基础上,进行不同参数组合混凝土的性能验证。根据不同参数组合混凝土性能验证的结果,选择工作性和力学性能满足设计要求的组合来研究大流动度路面混凝土的耐久性。为了比较科学、准确的评价混凝土的耐久性,本文主要研究了水胶比、胶凝材料用量、砂率、粉煤灰掺量等不同因素变化对大流动度路面混凝土的干缩性能、早期开裂性能、抗氯离子渗透性、抗冻性、耐磨性的影响规律;混凝土的力学性能与抗氯离子渗透性之间的关系以及混凝土经受冻融循环次数的变化对其抗折、抗压强度和脆性系数(压折比)的影响。路面混凝土的耐久性不足会影响其路用性能,并缩短使用寿命,可以通过原材料选择、配合比设计、施工与养护三个方面来提高大流动度路面混凝土的耐久性。
[Abstract]:With the increasing traffic volume and overloading phenomenon, pavement concrete is required to have higher strength and durability.The slump of concrete mixture with large flow degree is above 160mm, with the collapse extension of 50cm~60cm, good construction and easiness, easy filling and dense, which can effectively improve the construction progress, ensure the engineering quality and reduce the environmental pollution.After setting and hardening, it has excellent mechanical properties and durability.In this paper, the durability of pavement concrete with large fluidity is studied through laboratory tests.Starting from the raw materials that affect the durability of concrete, the technical indexes of raw materials are tested according to the specifications, and the gradation design of aggregate is carried out, and then according to the design requirements of pavement concrete with large flow degree,Based on the calculation of mixing ratio parameters, four factors and four levels of orthogonal test table are selected to arrange the test, and the workability and mechanical properties of concrete under different parameter combinations are obtained, according to the results of orthogonal test,The influence of different test factors on the workability and mechanical properties of pavement concrete with large fluidity was analyzed by means of range analysis, and the optimum combination was selected from the orthogonal test table.And eliminate the combination that does not meet the design requirements of pavement concrete with large fluidity (slump above 160mm, flexural strength above 5.0MPa, compressive strength C30), and on the basis of better combination, verify the performance of composite concrete with different parameters.According to the results of performance verification of concrete with different parameters, the durability of pavement concrete with large fluidity is studied by choosing the combination of workability and mechanical properties to meet the design requirements.In order to evaluate the durability of concrete scientifically and accurately, this paper mainly studies the dry shrinkage and early cracking performance of pavement concrete with high flow rate, such as water / binder ratio, cement content, sand ratio, fly ash content, etc.The effect of chloride ion permeability, freezing resistance and wear resistance, the relationship between mechanical properties of concrete and chloride ion resistance and the bending resistance of concrete subjected to freeze-thaw cycles,The influence of compressive strength and brittleness coefficient (crimp ratio).The insufficient durability of pavement concrete will affect its road performance and shorten its service life. The durability of pavement concrete can be improved by three aspects: raw material selection, mix ratio design, construction and maintenance.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U414

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