摘 要

混凝土内部集料-水泥石界面过渡区的结构与性质对混凝土的宏观力学性能有着重要的影响，同时也是Cl^-等有害离子的渗透通道，影响着混凝土的耐久性能。过去人们为改善混凝土的脆性或者耐久性，往往在混凝土水泥石中掺入聚合物乳液、矿物掺合料等功能组分，然而存在掺量高、效果不突出、结构与性能难以稳定调控等问题。本文利用乳化沥青包裹集料的方式来对混凝土界面过渡区进行改性，并通过宏观力学性能测试、渗透性能测试以及微观SEM扫描分析等测试方法对改性前后混凝土的性能进行评估。

实验初期，研究了不同集料包裹沥青量(0、2%、4%)对混凝土力学性能与耐久性能的影响。探究结果发现：随着沥青包裹量的增加，混凝土强度明显下降，其中4%所对应的实验组抗压强度相比空白对照组而言下降了53.15%，2%的实验组下降了14.05%；在乳化沥青包裹集料所制得的混凝土的压应力单轴应力-应变试验中，发现应力-应变曲线的反弯点变得不明显，下降段趋于平缓，说明混凝土受压达到极限压应力后，断裂能释放与裂缝扩展速率下降，韧性改善。我们发现同时与空白组对比，乳化沥青包裹组的氯离子迁移系数较低，其中2%的实验组的氯离子渗透系数比空白组而言降低了26.96%，4%的实验组下降了27.83%，表明乳化沥青改性后的集料-水泥石界面过渡区，对混凝土的韧性、抗渗性能有积极作用，但也会带来混凝土强度降低、易于变形等问题。

在初期实验的基础上，为了兼顾混凝土的力学性能和抗渗透性能，研究了1%沥青包裹集料，不同包裹集料与未处理集料所占比例对混凝土性能的影响规律。在混凝土力学性能测试方面，掺30%包裹集料性能较为优异，相比完全包裹的实验组抗压强度提高了27.67%，掺50%的只提升了11.95%，而掺70%的提升的更少只有1.57%，在不同比例掺杂包裹集料的同时，乳化沥青作为界面过渡区的弱化成分，使得沥青界面过渡区成为了应力集中区，在外界压力的条件下，裂缝大量在沥青界面上形成并扩展，导致抗压效果更差，而30%处理集料混凝土强度有所提高，且应变趋势也更宽，这是因为混凝土内部大部分的界面为集料—水泥石界面，在抗压过程中，集料—水泥石界面能够承受更大的压力，使得乳化沥青的弹性特性得以更大的发挥，因此更佳符合我们想要在保持混凝土强度的前提下更加凸显出乳化沥青的聚合物特性的目的。同时根据RCM与毛细吸水法实验发现，随着沥青包裹集料掺杂比例的提高，氯离子渗透系数也随之降低，经过沥青包裹处理后所形成的界面过渡区确实对氯离子有阻碍作用，可起到提高耐久性的作用。

关键词：界面过渡区；乳化沥青；力学性能；抗渗性能

Abstract

Concrete internal set structure and properties of coarse aggregate and cement paste interfacial transition zone of concrete macroscopic mechanical properties have an important influence, and Cl - and other harmful ion permeable channel, affecting the durability of concrete. In the past, people in order to improve the brittleness of concrete and durability, often in stone concrete incorporation emulsion polymer and mineral synthetic materials such as functional components, however, has high dosage, the effect is prominent, structure and properties of stability is difficult to control. The emulsified bitumen coated aggregate interfacial transition zone of concrete were modified, and the test methods of performance testing and SEM scanning analysis by macro mechanical test and permeation of concrete before and after the performance of the modified to evaluate.

In the early stage of the experiment, the influence of the different aggregates (0, 2%, 4%) on the mechanical properties and durability of concrete was studied. The results show that with increasing the amount of asphalt, concrete strength decreased, which compared compressive strength of 4% corresponding control group decreased by 53.15%, 2% of the experimental group dropped by 14.05%, but in under the action of stress, concrete strain range increased; at the same time compared with the control group, the chloride ion migration the coefficient of emulsified asphalt wrapping group is low, the chloride ion permeability coefficient of experimental group 2% was 26.96% lower than the control group, the experimental group 4% decreased by 27.83%, showed that the emulsified asphalt modified aggregate after cement paste interfacial transition zone of concrete, toughness, anti permeability performance has a positive effect, but it will bring about the decrease in concrete strength, easy deformation etc..

In early experiments, in order to take into account the mechanical properties of concrete and anti permeability of 1% bitumen coated aggregate, parcels of different aggregate and untreated aggregate accounts for the effect of proportion on the properties of concrete. In the aspect of concrete mechanical performance test, with 30% package aggregate performance is excellent, compared to the experimental group completely wrapped compressive strength increased by 27.67%, with 50% only increased by 11.95%, while 70% increase less with only 1.57%, in different proportion of doping aggregate package at the same time, emulsified asphalt as weakening component interface transition zone that makes the asphalt interface transition zone become the stress concentration zone, the external pressure under the condition of a large number of cracks in the asphalt on the interface formation and expansion, leading to compressive effect worse and 30% aggregate concrete strength is increased, and the strain trend is more wide, this is because most of the interface is set inside the concrete the interface material of cement stone, in the compression process, aggregate cement paste interface can withstand greater pressure, the elastic properties of asphalt emulsion to play more, because This is better in line with the purpose of the polymer properties that we want to be more convex to show the properties of the emulsified asphalt in the condition that the strength of the concrete is maintained. At the same time, according to the experiment of RCM and capillary water absorption, it can be concluded that the emulsified asphalt can be used as interface transition zone, which can improve the density of the concrete interface transition zone.

Key words:Interfacial transition zone; Emulsified asphalt; Mechanical properties; Penetration resistance

目 录

摘　要 I

Abstract II

第一章 绪 论 1

1.1 研究背景及意义 1

1.2 国内外研究进展 2

1.3 研究内容与方法 5

第二章 实验原材料及测试方法 6

2.1 实验原材料 6

2.1.1 水泥 6

2.1.2 粉煤灰 6

2.1.3 矿粉 7

2.1.4 集料 7

2.1.5 减水剂 8

2.1.6 乳化沥青 8

2.2 实验方法 8

2.2.1 混凝土工作性能测试 8

2.2.2 力学性能测试 8

2.2.2.1 抗压强度测试 8

2.2.2.2 单轴压应力—应变全曲线测试 8

2.2.2.3 四点弯曲荷载—挠度全曲线测试 9

2.2.3 混凝土抗渗性能测试 9

2.2.3.1 快速氯离子迁移系数测试 (RCM法) 9

2.2.3.2 混凝土毛细吸水测试 9

2.2.4 微观形貌测试 10

2.2.5 混凝土的搅拌、成型及养护 10

2.2.6 实验配合比设计 10

第三章 实验结果与分析 12

3.1 初期实验测试结果与分析 12

3.1.1 初期实验抗压实验结果与分析 12

3.1.2 初期实验单轴压应力—应变实验结果与分析 12