论文总字数：30061字

摘 要

论文作者签名：＿＿＿＿＿导师签名：＿＿＿＿日期：＿＿＿＿

新型固化剂处理现场重金属污染土的性能效果研究

21813112 蔡兆毅

指导教师 王菲

摘要

我国目前正面临着较为严重的土壤重金属污染问题，而固化稳定化（S/S）技术作为最经济高效的污染土修复技术正被广泛应用于国内外的重金属污染场地。其中，传统波特兰水泥作为最常见的一种固化剂，不仅在生产过程中会消耗大量不可再生资源与能源，同时还伴随这巨大的空气污染，是一种不可再生、不绿色环保的建筑材料。因此本文提出用高炉矿渣微粉（GGBS）代替水泥作为固化剂中的主要成分，并利用氧化镁（MgO）并辅以氧化钙（CaO）作为碱性激发剂，制成氧化镁基GGBS固化剂，并同时结合关于温度效益对土壤造成的影响，对该新型固化剂进行了以下研究：

（1）物理化学特性研究： MgO-CaO-GGBS固化污染土样的含水率、pH值均低于水泥固化污染土样，且在本文测试的三个MgO-CaO-GGBS固化剂掺量（5%、10%、15%）中，固化剂掺量越高，试样含水率越低、但在pH值上该规律反映不明显。

（2）力学性能研究： 试验测得的水泥固化污染土试样的无侧限抗压强度普遍大于MgO-CaO-GGBS固化污染土样，各掺量MgO-CaO-GGBS固化污染土样早期强度仅有同掺量水泥固化土强度的约30%至40%。

（3）环境安全性研究：掺量为10%的水泥固化污染土试样在浸出试验中的平均表现相似于同等掺量的MgO-CaO-GGBS固化污染土试样，且掺量在实验范围内的MgO-CaO-GGBS固化污染土试样的浸出浓度随掺量增加而降低。

（4）耐久性能研究：PC固化污染土试样的耐干湿循环性能和耐冻融循环性能均略好于MgO-CaO-GGBS固化污染土试样，且试验范围内MgO-CaO-GGBS固化剂掺量越高，固化污染土试样的耐干湿循环性能越好。但耐冻融循环性能几乎不受固化剂掺量影响。

（5）温度效应对固化剂性能效果的影响：无侧限抗压强度实验和毒性浸出试验所反映出的温度效应对重金属固化土的影响规律基本一致，即适当提高养护温度可以促进固化土内水化反应的进行，增加试样强度，提升对重金属的固化稳定化能力；而低温养护则会抑制这一过程。

通过上述结论可以表明，一定掺量的MgO-CaO-GGBS固化剂在环境安全性上由于普通水泥固化剂；且若继续提高固化剂掺量，其强度特性也可能超过普通水泥固化剂，可以将其作为水泥固化剂的代替品固化重金属污染场地。且一定的高温温度对于固化剂充分发挥其性能效果有促进作用。

关键词：氧化镁基GGBS固化剂；重金属污染土；温度效应；力学性能；环境安全性；耐久性。

Study on the Effect of New Type of Curing Agent on Heavy Metal Contaminated Soil

21813112 Cai Zhao-yi

Supervised by Professor Wang Fei

Abstract

China is currently facing a serious problem of heavy metal pollution of soil, and the stabilization and solidification (S/S) technology is being widely used as the most economical and effective contaminated soil remediation technology in heavy metal contaminated sites at home and abroad. The traditional Portland cement (PC) , which is the most common kind of curing agent, is a non-renewable, non-environmentally friendly building material because it will not only consume a lot of non-renewable resources and energy, but also emit a large amount of air pollution during its production process. Therefore, this paper proposed that ground granulated blast furnace slag powder (GGBS) would take the place of cement as the main components of a curing agent, together with magnesium oxide (MgO) and supplemented by calcium oxide (CaO) as basic activators. So the following studies were carried out on the new curing agent in combination with the effect of different curing temperatures on soil:

(1) The physical-chemical characters: The moisture content and the pH of the MgO-CaO-GGBS solidified soils are lower than those of the PC solidified soils. And moisture and tend to drop when raising the content of the MgO-CaO-GGBS among the tested three while the pH does not follow this regular.

(2) The mechanical characters: The unconfined compressive strength of the PC solidified soil samples are generally greater than that of the MgO-CaO-GGBS solidified soil samples. The early strength of the MgO-CaO-GGBS solidified contaminated soil samples is only about 30% to 40% as much as that of PC samples.

(3) The environmental security characters: The average performance of the PC samples in the leaching test is similar to the MgO-CaO-GGBS solid contaminated soil samples with the same content. And the leaching concentration of contaminated soil samples decreases while the amount of MgO-CaO-GGBS increases from 5% to 15%.

(4) The durability characters:

(5) The effect of the curing temperature: Both the unconfined compressive strength test and the leaching test lead to a conclusion that a certain high temperature (45℃) can promote the hydration reaction in the solidified soil, and also increase the strength of the samples, enhance the solidification and stabilization ability to heavy metals, and the low curing temperature will inhibit this process.

The investigation results reveal that a certain amount of MgO-CaO-GGBS performs better than the Portland cement in safety aspect. And if the amount continue to increase, its strength characteristics is also considered to exceed the Portland cement's. So it is possible for MgO-CaO-GGBS to act as a substitute for cement curing agent in heavy metal contaminated sites. And a certain high curing temperature can also give full play to its curing performance.

Key words： magnesium oxide-based GGBS curing agent; heavy metal contaminated soil; temperature effect; mechanical characters; environmental security characters; durability characters.

目 录

摘要 I

Abstract III

第一章 绪论 1

1.1 研究背景与研究意义 1

1.2 温度对重金属污染土固化效果的影响 2

1.3 MgO-CaO-GGBS新型固化剂及其应用 3

1.3.1 粒化高炉矿渣粉 3

1.3.2 基于GGBS的碱性激发水泥 3

1.4 研究现状总结分析 4

1.5 本文研究内容及技术路线 5

1.5.1 主要研究内容 5

1.5.2 研究技术路线 5

第二章 试验内容与试验方法 7

2.1 实验材料 7

2.1.1 试验土样 7

2.1.2 粒化高炉矿渣粉（GGBS） 7

2.1.3 氧化镁（MgO） 8

2.1.4 水泥（PC） 9

2.2 制样方案及实验方法 9

2.2.1 试样制备与养护 9

2.2.2 无侧限抗压强度实验 10

2.2.3 TCLP浸出实验 11

2.2.4 干湿循环试验 12

2.2.5 冻融循环试验 12

第三章 MgO-CaO-GGBS固化污染土的物理化学特性与强度特性 14

3.1 外观分析 14

3.2 含水率（） 15

3.3 pH值 16

3.4 无侧限抗压强度 18

3.5 本章小结 20

第四章 MgO-CaO-GGBS固化污染土的环境安全性 21

4.1 固化污染土的各重金属溶出浓度分析 21

4.2 本章小结 22

第五章 MgO-CaO-GGBS固化污染土的耐久性 24

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