摘 要

AAR（Alkali-Aggregate Reaction，又称碱-集料反应）被许多专家称之为混凝土的癌症，是影响混凝土强度和持久性的重要因素之一。自1940年该反应被发现以来，被多个国家媒体报道了其在混凝土工程中的破坏效果。该反应的原理是因为混凝土集料中的某些活性矿物与混凝土中的碱溶液发生化学反应，从而导致了生成物体积的膨胀与扩大，随之而来产生的结果便是混凝土本身的结构遭到破坏。混凝土工程中发生的碱集料反应使得混凝土结构遭到破坏，而被破坏的混凝土结构维修难度极大，其维修后续成本有可能比他本身的工程造价还要昂贵，该反应在混凝土工程领域造成了数以亿计的直接或间接的经济损失。作为影响混凝土耐久性的重要因素，该反应引起了世界各国科技工作者和工程技术人员的高度关注，许多专家在各领域如：碱活性集料的鉴别方法、膨胀机理、膨胀的防止和抑制措施及对破坏诊断与评估方法等，通过对碱集料反应更为深入的研究与分析，寻求能抑制AAR的方法。

本文运用扫描电子显微镜(SEM)和 X-射线（XRD）等手段对白云石微粉（DM）与偏高岭土（MK）在水泥中的复合浆体产物进行了较为全面的分析。通过白云石微粉（DM）与偏高岭土（MK）在水泥中以不同质量比复合，并且分别加入两种集料来深入的研究分析所形成产物（这两种集料我们分别采用徐州的和铁科院的）。白云石是石灰石的伴生矿物，部分含白云石集料与碱发生碱-碳酸盐反应(ACR)导致混凝土膨胀开裂。然而，白云石以微粉料的形式掺入混凝土中对AAR影响尚不明确。本文以石灰石微粉作参照，首先研究了不同掺量的白云石微粉对水泥净浆膨胀性能的影响。在此基础上，采用中国快速砂棒法（CAMBT），研究了白云石微粉单掺及与偏高岭土复掺对水泥抗ASR和ACR性能的影响。实验使用比长仪测量上述样品在80℃，1mol/L的NaOH溶液中养护3 d、7 d、14 d、21 d、28 d以及35 d的线性膨胀率，并对测试样品进行XRD分析，结果显示：

（1）与石灰石微粉相比，含白云石微粉浆体微膨胀效应更加显著，且掺量愈大效应愈明显；（2）白云石微粉并没有劣化水泥抗AAR性能，且白云石微粉与偏高岭土复掺对AAR膨胀的抑制效果稍好于石灰石微粉。

关键词：白云石微粉，偏高岭土，碱-集料反应，强度

Dolomite powder and metakaolin composite effect on the performance of concrete resistance to AAR

ABSTRACT

AAR (Alkali - Aggregate Reaction, also known as the Alkali - Aggregate Reaction) by many experts called the concrete cancer, is one of the important factors that affect the concrete strength and durability.Since the reaction was found in 1940, by multiple state media reported that the damage in concrete engineering effects.The principle of the reaction is because some of the active mineral aggregate concrete and concrete alkali solution of chemical reaction, which leads to the products volume expansion and expansion, is the result of a subsequent damage to the structure of concrete itself.JianJiLiao reaction in concrete engineering makes the concrete structure is destroyed, and the destruction of concrete structure are extremely hard maintenance, the maintenance cost of subsequent may be better than his own project cost is expensive, the reaction in concrete engineering caused hundreds of millions of direct or indirect economic loss.As the important influence factors of concrete durability, the reaction caused the world science and technology workers and engineering technical personnel's high attention, many experts in various fields such as: aggregate alkali activity of identification method, the mechanism of expansion, the expansion of the measures to prevent and curb and for damage diagnosis and evaluation method, through the JianJiLiao respond more in-depth research and analysis, seek method can restrain the AAR.                                   
In this paper, by using scanning electron microscope (SEM) and X - ray (XRD), and other means of dolomite powder (DM) and metakaolin (MK) in cement composite slurry product has carried on the comprehensive analysis, the determination of the JianJiLiao reaction degree and use accelerated mortar bar method (RILEM AAR - 2) and autoclave method (CECS 48) evaluated the AAR expansion of slurry.By dolomite powder (DM) and metakaolin (MK) in cement with different quality than the compound, and separately in two aggregate to in-depth research and analysis of product (both aggregate we respectively adopt xuzhou and TieKeYuan).Dolomite and Limestone are associated Minerals. Aggregate contain dolomite will lead to Alkali - carbonate reaction. But it is not certain that whether dolomite in form of powder can lead such reaction. This issue designed different amounts of dolomite powder incorporated PⅡ52.5 R cement paste to study the impact on cement expansion and using CAMBT to study dolomite powder’s impact on performance of anti-ASR and anti-ACR of concrete, which contains silicon aggregate and dolomitic aggregate. Samples were measured at 80 ℃, 1mol / L of NaOH in conservation 3 d, 7 d, 14 d, 21 d, 28 d and 35d of the linear expansion coefficient, and the test sample was analyzed by XRD. The results have proved the following conclusions:

(1) Compared to the limestone powder concerned, dolomite’s role in promoting the expansion of cement paste is more effective. With the increase of incorporation, its role in promoting the expansion is more and more significant;

(2) Doped single, complex mixed dolomite have no significant deterioration of concrete anti AAR performance. Dolomite powder and metakaolin complex mixed concrete inhibit expansion slightly better than limestone powder mixed with metakaolin complex.

Key words: dolomite powder, metakaolin and alkali - aggregate reaction, strength

目录

摘 要 4

ABSTRACT 5

第一章 绪论 7

1.1 引言 7

1.2 碱白云石反应 8

1.3 碱-硅酸反应（ASR）机理 9

1.4 碱-碳酸盐反应（ACR）机理 10

1.5 膨胀机理 11

1.5.1 碱白云石反应膨胀机理 11

1.5.2 碱-硅酸反应膨胀机理 12

1.5.3 碱粘土反应膨胀机理 12

1.6 研究内容、目的和意义 12

第二章原材料与试验方法 20

2.1 原材料 20

2.1.1 水泥 20

2.1.2 石灰石粉 20

2.1.3 白云石粉 20

2.1.4 偏高岭土 20

2.1.5 白云质集料 21

2.1.6 硅质集料 21

2.2 实验仪器及设备 21

2.3 白云石微粉对水泥净浆膨胀性能的影响 21

2.3.1 配料比 21

2.3.2 实验方法 22

2.4 白云石微粉对AAR性能的影响 23

2.4.1 配料比 23

2.4.2 实验方法 24

第三章 实验结果 25

3.1 白云石微粉对水泥净浆膨胀性能的影响 25

3.2 白云石微粉对水泥抗AAR性能影响 26

3.2.1 白云石微粉对水泥抗ASR性能影响 26

3.2.2 白云石微粉抗ACR性能 28

第四章 样品XRD分析 32

4.1 水泥净浆XRD分析 32

4.2 白云石微粉对AAR性能影响XRD分析 33

第五章 结论与展望 24

5.1结论 24

5.2展望 24

参考文献 25

致谢 28

第一章 绪论

1.1 引言

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