论文总字数：37676字

摘 要

高强度高延性水泥基复合材料（High Strength High Ductility Cementitious Composites，HS-HDCC）是一种采用中等纤维体积掺量制成的纤维增强水泥基复合材料，具有应变硬化和多缝开裂的特性，是高性能纤维增强型水泥基复合材料中的一种。由纳米级颗粒组成的矿物掺合料硅灰已成为高性能水泥基复合材料的首选，但研究发现，普通工业硅灰容易发生自发团聚，导致硅灰表面活性降低，从而削弱了硅灰的实际使用性能，因此，如何减少或消除硅灰颗粒的团聚效应是本研究的首要问题，此外，对HS-HDCC的成功制备是本研究的另一难点。

首先，本文提出一种新的硅灰分散方法：选用工业硅灰为生态纳米材料，氨基硅烷为表面修饰剂，成功实现了将硅烷接枝到硅灰表面。然后本文通过多种表征方法（激光粒度分析、表面电位分析、紫外光谱分析、SEM等）来探究氨基硅烷对硅灰的分散机理。结果为：经改性后，硅灰表面电位从-21提高到 3，极大增强了对阴离子减水剂的吸附能力；吸附量从5mg·g^-1提高到8mg·g^-1，结合表面电位实验证明了改性硅灰对减水剂的吸附量有显著提升；再观察改性硅灰和工业硅灰的粒径分布对比图和SEM对比图，可以看出改性硅灰的分散性显著增加、颗粒之间的界面更为清晰；证实了本文所提分散方法的合理性。同时本研究对比了改性前后硅灰对水泥胶砂的力学性能的影响，结果有效证实了改性硅灰对力学性能的改善。

在生态纳米材料硅灰成功改性的基础上，本文从原材料优选、配合比设计、关键性能检测等几个方面对HS-HDCC进行了系统的研究。以改性硅灰代替工业硅灰作为原料设计合适的配合比并测试了HS-HDCC砂浆基体的流变性能，为保证纤维在浆体中的分散均匀性，本文控制水泥胶砂的塑性粘度在合理的范围内，并依此设计了HS-HDCC的配合比，为HS-HDCC的成功制备提供了前提。

最后，本文对比了钢纤维、聚乙烯醇(PVA)纤维和超高分子量聚乙烯（PE）纤维单掺及复掺时对水泥基复合材料力学性能的影响，以及掺入粘度修饰剂对水泥基复合材料力学性能的影响，最终成功制备出抗压强度达到100MPa，极限拉伸应变超过3%，四点弯曲跨中挠度超过10mm的高强高延性水泥基复合材料，具体配合比为：PE纤维体积掺量2%、水胶比0.23、硅灰占粉料质量分数为0.30、稠度调节剂占粉料质量分数为0.10。

关键词：纳米材料；表面修饰；表征方法；HS-HDCC；流变性能；力学性能。

Abstract

High strength-high ductility cementitious composites(HS-HDCC), which are fiber reinforced cementitious composites blent with secondary fiber volume content, are a kind of high performance cement-based materials, possessing the characteristic of strain-hardening and multiple cracking. Although mineral admixture silica fume made up of nano-particles has already been the first choice for high performance cement-based material, it is found out that traditional commercial silica fume is apt to spontaneous aggregation, which lowers the surfactivity of silica fume and results in weakening the actual performance. Therefore, it is the primary task of our research that how to reduce or eliminate the aggregation effect. Besides, how to prepare HS-HDCC brings another challenge into our research as well.

First of all, our research puts forward a new dispersion method of silica fume: using commercial silica fume as eco-nano matirials and using amino silane as surface modifier, and achieves that grafting the silane to the surface of silica fume. Then our research probes into the dispersion mechanism of silica fume through a variety of characterization method(Laser particle size analysis, zeta potential analysis, ultraviolet upectrum analysis, SEM and etc.). It is found out that: (1)After modification, the zeta potential of silica fume was increased from -21 to 3, greatly strengthing the adsorbability to anionic water reducing agent. (2)The adsorption capacity increased from 5mg·g^-1to 8mg·g^-1. Along with zeta potential analysis, it shows that modified silica fume greatly improve the water reducing agent adsorption. (3) Researching the particle size distribution figures and SEM photos, it displays that modified silica fume presents better dispersibility and clearer interface between particles. These findings support the rationality of our proposed dispersion method. Besides, our research compares the impact of silica fume on the mechanical property of the cement paste before and after modification, which proves the positive effect of modified silica fume on mechanical property.

Based on the foundation of the successful modification of eco-nano materials, we study HS-HDCC systematically from raw materials selection, mix proportion design and key performance test. Instead of commercial silica fume, we use modified silica fume as raw materials to design the mix proportion and detect the rheological property of HS-HDCC cement paste. To guarantee the dispersion uniformity, we control the plastic viscosity of cement paste. On account of this, we designed the mix proportion of HS-HDCC, which provides the basis of successfully preparing HS-HDCC.

Finally, our research contrasts the effect to cementitious composites mechanical property among steel fiber, PVA fiber and PE fiber, with single addition and compound addition. Meanwhile, we studied how viscosity modifier affect the mechanical property of cementitious composites. Ultimately we successfully prepared the required HS-HDCC, which compression strength reaches to 100MPa, ultimate tensile strain exceeds 3% and four-point bending deflection exceeds 10mm. The best mix proportion is that PE fiber volume content is 2%, W/C is 0.23, silica fume dosage is 0.30 and consistency regulator dosage is 0.10.

KEY WORDS: Nano-materials, Surface modification, characterization methods, HS-HDCC, Rheological property, Mechanical property.

目录

摘 要 I

Abstract II

第一章 绪 论 1

1.1 研究背景与意义 1

1.2 国内外研究现状 2

1.2.1 生态纳米材料改性的研究现状 2

1.2.2 HS-HDCC国内外的研究进展 5

1.3.3存在问题与研究难点 8

1.3 技术路线、技术要求和研究难点 8

1.3.1 技术路线与主要研究内容 8

1.3.2 设计目标 9

第二章 原材料与实验方法 10

2.1 实验原材料 10

2.1.1 水泥（简写为C） 10

2.1.2 硅灰（简写为SF） 10

2.1.3 稠度调节剂（简写为CR） 11

2.1.4 水（简写为W） 11

2.1.5 细集料（简写为A） 11

2.1.6 减水剂（简写为WR） 11

2.1.7 钢纤维（简写为STF） 11

2.1.8 聚乙烯醇纤维（简写为PVAF） 12

2.1.9 超高分子聚乙烯纤维（简写为PEF） 12

2.1.10 氨基硅烷（简写为AS） 12

2.2 实验仪器和测试方法 12

2.2.1 浆体流变性能测试 12

2.2.2 抗折抗压强度测定 13

2.2.3 四点弯曲实验 13

2.2.4 单轴拉伸实验 13

2.2.5 微观测试 14

第三章 生态纳米材料改性及表征方法 16

3.1 硅灰改性方法 16

3.2 硅灰改性表征结果 16

3.2.1 表面电位与减水剂吸附量结果 16

3.2.2 粒度分布结果与SEM形貌分析 18

3.2 力学性能比较 19

3.3 本章小结 20

第四章 HS-HDCC的设计与制备 21

4.1 配合比设计 21

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