摘 要

本文主要进行了混凝土抗冻性影响因素的研究。研究内容包括控制陶砂掺量研究其对蒸养混凝土的抗冻性能的影响、不同养护方式对混凝土抗冻性影响以及运用有限元建模研究细观层次的混凝土劈裂破坏原理。通过控制变量法进行试验，探讨各因素对混凝土抗冻性能的影响。试验结果表明：

1.冻融条件下相同配比的蒸汽养护混凝土的抗冻强度损失率、质量损失大于相同条件下的标养混凝土，其表面损伤程度比标准养护的混凝土更严重；

2.冻融条件相同、养护方式相同的情况下，掺入陶砂的蒸养混凝土强度损失率及质量损失率要明显小于不掺陶砂的蒸养混泥土。

3.蒸养混凝土细观劈裂分析得出混凝土失稳破坏实质上是由于其细观界面相处的微小裂缝产生、扩大直至宏观开裂的过程。

关键词 蒸养混凝土；冻融循环；细观力学

Abstract

In this paper, the influence factors of frost resistance of concrete are studied.The study included the effect of controlling the amount of ceramic sand on the frost resistance of steamed concrete, the influence of different curing methods on the frost resistance of concrete and the application of finite element modeling to study the meso-level concrete splitting strain principle.The influence of various factors on the frost resistance of concrete was studied by controlling the variable method. The results showed that:

1.The frost strength loss rate and mass loss of the same proportion of steam curing concrete under freezing and thawing condition are greater than the standard curing concrete under the same condition, and the surface damage degree is more serious than that of the standard curing concrete;

2.Freeze-thaw conditions are the same, the same conservation mode,the strength loss rate and mass loss rate of steamed concrete mixed with ceramic sand are obviously smaller than that of steamed concrete with no ceramic sand.

3.The analysis of concrete failure in the steamed concrete shows that the failure of concrete is mainly due to the small cracks in the mesoscopic interface and the process of expanding to the macroscopic cracking.

Key words steamed concrete; freeze-thaw cycle; micromanometry

目 录

第1章 绪论...............................................................1

1.1 研究背景及意义......................................................1

1.2 国内外现状..........................................................1

1.2.1 混凝土蒸汽养护工艺及研究现状....................................1

1.2.2 冻融破坏研究发展现状............................................3

1.3 本文主要研究内容....................................................4

1. 蒸养混凝土制备.....................................................5

2.1 原材料..............................................................5

2.2 试验所用配合比......................................................6

2.3 试验方案设计........................................................6

2.3.1 蒸养混凝土的制备及养护..........................................6

1. 蒸养混凝土冻融试验研究.............................................9

3.1 混凝土的冻融试验方案................................................9

3.2 冻融试验结果分析....................................................10

3.2.1 冻融试件表观....................................................10

3.2.2 混凝土质量损失率................................................10

3.2.3 混凝土力学性能试验..............................................11

3.2.4 SEM电镜扫描结果................................................12

3.3 本章小结............................................................13

1. 蒸养混凝土细观尺度分析.............................................14

4.1 复合材料细观力学原理................................................14

4.2 蒸养混凝土细观劈裂分析..............................................15

4.2.1 引言............................................................15

4.2.2 蒸养混凝土细观数值模拟..........................................15

1. 结论与展望.........................................................18

5.1 结论................................................................18

5.2 展望................................................................18

参考文献..................................................................20

致谢......................................................................21

第1章 绪论

1.1 研究背景及意义

混凝土是近年施工中应用最普遍的材料之一。和其他建筑所用材料相比，混凝土具有来源广泛、防火性能好、施工成本低、施工工艺简单多变、可塑性强、高强耐久性等多个独特优势^[1]。随着建筑业的快速发展，混凝土工业生产试件不仅质量好，而且制造方法简单，施工的时间短，一般采用蒸汽养护工艺使混凝土构件获得较高早期强度。

在中国的建设项目中，混凝土构造是应用最广泛的。随着城镇以及工程建设和改造，混凝土试件的需求量逐年增加，加上我国建筑行业存在建设量大、建筑速度快、建筑人员专业水平相对较低等特点，混凝土建筑或多或少存在着各种耐久性问题。在环境因素和内部因素的共同影响下，在建筑工程设计使用时间内，不用花费很多资金去维护运行，就能构维持长时间的强度以及外观完整的能力叫做混凝土构件的耐久性。