论文总字数：24884字

摘 要

随着社会的进步、科技的发展，在工程中对于混凝土材料的性能要求也越来越高。超高性能水泥基材料是一种力学性能和耐久性能都十分优异的新型建筑材料，广泛用于土木、建筑、水利、交通、国防防护等各个领域。超高性能水泥基材料的制备技术、力学性能及微结构形成机理逐渐成为国内外的研究热点。

超高性能水泥基材料制备的前提条件是极低的水胶比，可是目前国外应用于超高性能水泥基材料中的超细粉体材料、微细金属纤维等原材料价格十分昂贵、制备和养护工艺复杂、能耗大，从而制约了该材料的应用与发展。近年来采用的矿物掺合料多元复合技术可以发挥材料的优势互补效应，降低超高性能水泥基材料的成本。本文基于大量的前期实验的研究成果，通过复掺稻壳灰、偏高岭土、粉煤灰、硅灰等材料，研究多种材料复掺对超高性能水泥基材料力学性能、微观结构等的影响规律，揭示了复掺时不同稻壳灰掺量对超高性能水泥基材料性能影响的规律。

本文采用复掺技术，研究不同掺合料掺量、不同龄期条件下超高性能水泥基材料的力学性能。结果表明当稻壳灰与偏高岭土等复掺时可以有效的提高混凝土力学性能，并且当掺量为10%左右时提升最为明显。

本文采用多种微观分析测试技术揭示该材料的微结构形成机理，采用XRD实验定量分析了水泥基材料在不同龄期时的水化产物，实验的结果表明，复掺稻壳灰后可以进一步促进水泥的水化，并且可以与水化生成的Ca(OH)₂反应，避免了Ca(OH)₂在界面区的聚集，进一步促进水泥的水化。MIP实验系统研究不同龄期条件下复合材料的孔结构演变规律，结果表明复掺稻壳灰的后可明显降低了孔隙率，增加了无害孔的数量，同时减少了有害孔的数量，整个结构变的更加致密。从微观结构分析了掺入稻壳灰可以提升超高性能水泥基材料力学性能的原因。

关键词：超高性能水泥基复合材料；稻壳灰；偏高岭土；力学性能；微观结构

Abstract

With the development of technology and the improvement of society, materials used in project are in demand of higher performance. UHPC is a new kind of building material that has high strength and durability. It has high strength, high toughness and low porosity and other characteristics, especially its excellent mechanical properties make it a big hit in research.

An extremely low water-cement ratio is a prerequisite for UHPC material preparation, but the fine metal fiber and other raw materials prices are very expensive that currently used in UHPC material. In recent years, the use of mineral admixtures multiple composite technology can play a complementary effect materials and reduce the cost of UHPC material. In this research, a lot of preliminary experiments and existing research results at home and abroad are done, by mixing with rice husk ash, metakaolin, fly ash, silica fume and other materials to study the effect about strength and durability of UHPC. And indicate the way that how different materials influence the performance of UHPC.

In this study, we test the strength of UHPC in different age by controlling the percentage of RHA in UHPC. And the result shows when RHA and metakaolin are both added into UHPC can effectively increase the strength of concrete. And when the percentage of RHA is 10% the increase is most obvious.

The XRD experiment quantitative analysis the hydration products in different age. And the result shows RHA can promote the hydration of cement. It also can react with Ca(OH)₂, prevent it from gathering around interface region. MIP experiment measuring the porosity, pore size distribution curve plotted, visually show the improvement of the pore structure after incorporation of rice husk ash. The incorporation of rice husk ash reduced porosity, increase the number of sound holes, while reducing the number of harmful holes, the entire structure becomes denser. Microstructural analysis the reasons for the incorporation of rice husk ash can enhance the mechanical properties of UHPC materials.

Keywords: UHPC, rice husk ash, metkaolin, mechanical properties; microstructure

目 录

摘 要 I

Abstract II

第一章 绪论 1

1.1 偏高岭土对混凝土性能影响的研究现状 1

1.1.1 对孔结构影响 2

1.1.2 对化学收缩和自收缩的影响 2

1.1.3 对力学性能的影响 2

1.1.4 对耐久性的影响 3

1.15 对混凝土工作性能的影响 4

1.2 稻壳灰对混凝土性能影响的研究现状 4

1.2.1 稻壳灰对流动度的影响 5

1.2.2 稻壳灰与硅灰掺量对混凝土抗压强度的影响 6

1.2.3 稻壳灰粒径变化对混凝土强度的影响 7

1.2.4 稻壳灰对混凝土孔结构的影响 7

1.3本文主要研究内容 8

第二章 原材料与实验方法 10

2.1 实验材料 10

2.1.1 粉煤灰 10

2.1.2 水泥 10

2.1.3 硅灰 10

2.1.4 偏高岭土 11

2.1.6 细集料 12

2.1.7 减水剂 12

2.2 实验方法 12

2.2.1 砂浆试件成型养护 12

2.2.2 力学性能测试 12

2.2.3 微结构分析 12

第三章 稻壳灰的制备及水泥基复合的力学性能 13

3.1 稻壳灰制备与分析 13

3.2 超高性能水泥基材料的力学性能 14

3.3 本章小结 16

第四章 超高性能水泥基材料微结构分析 17

4.1 水化热放热曲线 17

4.2基于全谱拟合Rietveld方法的水化程度分析 17

4.2.1 Rietveld方法基本原理 17

4.2.2 不同龄期、不同配比物相含量分析 18

4.3 压汞法（MIP）实验分析 20

4.4 SEM图像分析 25

4.5 本章小结 26

第五章 结论与展望 27

5.1 结论 27

5.2 展望 27

致 谢 28

参考文献 29

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