再生粗骨料及矿物掺合料对再生混凝土抗冻性能的影响研究

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3.0 侯斌 2024-11-19 4 4 2.23MB 74 页 15积分

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摘要

由于天然骨料的来源广泛和价格低廉，人们对其的滥采滥用造成了严重的资

源枯竭和环境污染。另外，建筑的更新和市政动迁规模的不断加大会产生大量的

废弃混凝土，如不能妥善处置，不仅会侵占大量耕地还会污染环境。再生混凝土

应运而生，再生混凝土是利用废弃混凝土，经过破碎，清洗，分级后，按照一定

的比例混合形成骨料，以此部分或全部代替天然骨料配制的混凝土。国内外学者

通过对再生混凝土的力学性能的研究，分析了其在实际工程中广泛应用的可能性。

本文通过对大量不同粗骨料取代率，单掺粉煤灰、硅灰和复掺粉煤灰、硅灰的再

生混凝土进行冻融循环试验，分析其力学性能及抗冻性能的变化，并建立了冻融

循环后相关冻融损伤模型，主要开展的工作及得出的相关结论如下：

（1）介绍了当前国内外关于再生混凝土抗冻性能方面的研究现状。

（2）研究不同粗骨料取代率对再生混凝土抗冻性能的影响，对比动弹模量和

抗压峰值应力的衰变情况，得出再生混凝土力学性能的衰变趋势，推断出再生混

凝土在不同再生粗骨料取代率下抗冻性能的变化情况。根据试验结果可知，随着

再生粗骨料取代量的增多，再生混凝土的动弹模量及抗压强度进一步降低，抗冻

性能逐渐下降。同时推到了相对动弹模量的趋势线公式，对衰变规律进行初步模

拟分析。

（3）研究了当再生粗骨料取代率为 80%时，粉煤灰、硅灰单掺对混凝土抗

冻性能的影响。分别对粉煤灰掺量为 0%、

10%、

20%及硅灰掺量为 0%、

5%、

10%

的再生混凝土在 0-200 次冻融循环下的抗冻性能做出了分析，得出粉煤灰掺量

10%及硅灰掺量 5%时再生混凝土动弹模量及抗压强度有较明显提高，混凝土的抗

冻性能增强，而粉煤灰、硅灰掺量继续增加反而会降低混凝土的抗冻性能，甚至

低于普通硅酸盐混凝土的抗冻性能。

（4）分析研究当再生粗骨料取代率为 80%时，粉煤灰、硅灰复掺对再生混

凝土抗冻性能的影响。分别以粉煤灰掺量为 0、10%、20%时，0%、5%、10%的

硅灰掺量与之复掺，得出再生混凝土动弹模量及抗压强度的变化曲线；分析粉煤

灰、硅灰对再生混凝土的微观叠加影响，并推导出粉煤灰、硅灰耦合作用下再生

混凝土的冻融损伤模型，得出粉煤灰掺量和硅灰掺量对公式系数的影响函数，并

把理论曲线与试验数据曲线进行比较，回归系数 R2大于 0.9，模型公式较有参考

价值。

本文就再生混凝土的冻融试验、粉煤灰及硅灰掺量在混凝土抗冻性能的变化

过程中所起到的作用等方面进行了试验研究。依据试验结果，推导出相关的公式，

对再生混凝土抗冻性进行初步预测。相关结论具有合理性及实用意义，对提高再

生混凝土的抗冻性及大范围的推广有重要的意义。

关键词：再生粗骨料粉煤灰硅灰再生混凝土冻融循环抗冻性能

ABSTRACT

As the natural aggregate has extensive sources and the price is inexpensive,

exhaustive exploitation of mine caused serious resource depletion and environment

pollution. In addition, the update of construction and municipal movements have

produced a large amount of waste concrete, if not treated properly , it will not only

occupy a large number of cultivated land,but also pollute the environment. Recycled

concrete came into being, which uses the waste concrete.After crushing, washing,

grading, according to certain proportion aggregate mixture, instead of part or the whole

natural aggregate to manufacture concrete. Scholars researched on the mechanical

properties of recycled concrete,and analyzed the possibility of its widely application in

practical engineering. The effect of recycled concrete under freeze-thaw cycle based on

a large number of different coarse aggregate content single-doped fly ash or silicon

fume,admixed fly ash and silicon ash, are studied in the paper.The change of its

mechanical properties performance and mechanical properties after freezing and

thawing cycle , are also analysed.The main work and the related conclusions are as

follows:

(1) This paper introduces the current domestic and foreign research status on

recycled concrete frost resistance.

(2) Research on the effect of different coarse aggregate replacement ratio of

recycled concrete frost resistance performance and contrast the decay of elastic

modulus and peak compressive stress, then conclude that the recycled concrete's

mechanics performance decay trend, and deduce the antifreeze performance of

recycled concrete in different changes. According to the experimental result shows that

as the amount of recycled coarse aggregate content is increased, the loss modulus of

recycled concrete and compressive strength is reduced, antifreeze performance is

gradually declined. Meanwhile the relative dynamic modulus of trend line formula for

decay law preliminary simulation analysis is made.

(3) Single-doped fly ash orsilica fume concrete frost perfomance when recycled

coarse aggregate replacement rate of 80% are studied.Recycled concrete that

incorporated fly ash content of 0%, 10%, 20% and silica fume 0%, 5%, 10% to make

frost resistance under 0-200 freeze-thaw cycles,are analysed.Tt’s concluded that

pulverized coal ash content of 10% renewable and 5% silica fume concrete elastic

modulus and compressive strength and frost resistance of reinforced concretehave been

significantly improved,, but when fly ash, silica fume continue to increase ,the frost

resistance is reduced, even lower than the frost resistance of ordinary portland

concrete.

(4)The fly ash, mixed with silica fume iMPact on recycled concrete frost

resistance,when recycled coarse aggregate replacement rate is 80%,is analysed. A large

number of experiments, respectively, for 0,10% 20% of fly ash doped with 0%, 5%,

10% of silicon fume, recycled concrete elastic modulus and compression intensity

curve is drawn; fly ash, silica fume overlay microscopic iMPact of recycled concrete

and fly ash derived, freeze-thaw damage model regeneration silica fume concrete

under the coupling effect, fly ash and silica fume content on the formula coefficient

influence function, and the theoretical curves were coMPared with the experimental

data curve, the regression coefficient R2is greater than 0.9, the model equations are

more informative.

The paper is about freeze-thaw test concrete, fly ash and silica fume concrete frost

resistance in the process of change in the role of other aspects of the experimental

study, based on the test results, derived formula to regenerative frost resistance of

concrete forecast. Conclusions are reasonable and practical significance to improve the

promotion of recycled concrete frost resistance and a wide range of great significance.

Key word: recycled coarse aggregate fly ash Silica fume the

freeze-thaw cycle frost resistance

中文摘要

ABSTRACT

第一章绪论............................................................................................................... 1

1.1 研究背景与意义................................................................................................ 1

1.2 再生混凝土及其利用现状................................................................................ 2

1.2.1 再生混凝土生产工艺.................................................................................. 2

1.2.2 各国对再生混凝土的利用现状.................................................................. 2

1.3 粉煤灰、硅灰对混凝土性能的影响................................................................ 4

1.3.1 粉煤灰对混凝土性能的影响...................................................................... 4

1.3.2 硅灰对混凝土性能的影响.......................................................................... 4

1.4 混凝土冻融破坏机理......................................................................................... 5

1.5 再生混凝土冻融破坏研究................................................................................. 6

1.6 本文主要工作及技术路线................................................................................. 7

1.6.1 主要工作...................................................................................................... 7

1.6.2 技术路线...................................................................................................... 8

第二章再生混凝土试验方案..................................................................................... 9

2.1 混凝土抗冻试验方法......................................................................................... 9

2.1.1 各国的抗冻试验方法标准.......................................................................... 9

2.1.2 抗冻试验方法.............................................................................................. 9

2.1.3 动弹模量测试方法.................................................................................... 10

2.2 试验材料........................................................................................................... 10

2.3 试验仪器........................................................................................................... 11

2.4 试验步骤........................................................................................................... 12

2.5 试验数据处理................................................................................................... 13

2.5.1 数据处理原则............................................................................................ 13

2.5.2 质量损失率................................................................................................ 13

2.5.3 抗压强度.................................................................................................... 14

2.5.4 相对抗压强度............................................................................................ 14

2.5.5 混凝土动弹模量........................................................................................ 14

2.5.6 相对动弹模量............................................................................................ 14

第三章再生粗骨料取代率对混凝土抗冻性能的影响研究................................... 15

3.1 试验配合比设计............................................................................................... 15

3.2 冻融前后外观的比较分析............................................................................... 15

3.2.1 冻融前后混凝土的外观比较.................................................................... 15

3.2.2 表面损伤分析............................................................................................ 17

3.3 冻融前后的试块质量的比较........................................................................... 18

3.3.1 试验数据.................................................................................................... 18

3.3.2 再生混凝土质量损失................................................................................ 18

3.4 冻融前后的相对动弹模量的比较................................................................... 19

3.4.1 试验数据.................................................................................................... 19

3.4.2 再生混凝土动弹模量................................................................................ 20

3.4.3 结论............................................................................................................ 24

3.5 冻融前后抗压强度的比较............................................................................... 24

3.5.1 抗压试验及试验数据................................................................................ 24

3.5.2 再生混凝土的抗压强度............................................................................ 25

3.5.3 结论............................................................................................................ 26

3.6 本章小结........................................................................................................... 27

第四章粉煤灰、硅灰对再生混凝土抗冻性能的影响研究................................... 28

4.1 试验设计........................................................................................................... 28

4.2 冻融后外观比较............................................................................................... 29

4.2.1 粉煤灰混凝土、硅灰混凝土冻融表面.................................................... 29

4.2.2 结论............................................................................................................ 30

4.3 冻融后质量损失的比较................................................................................... 30

4.3.1 试验数据.................................................................................................... 30

4.3.2 粉煤灰、硅灰对再生混凝土冻融前后质量影响.................................... 31

4.3.3 结论............................................................................................................ 33

4.4 冻融循环后动弹模量的比较........................................................................... 33

4.4.1 试验数据.................................................................................................... 33

4.4.2 粉煤灰、硅灰对再生混凝土动弹模量的影响........................................ 34

4.4.3 结论............................................................................................................ 36

4.5 冻融后抗压强度的比较................................................................................... 36

4.5.1 试验数据.................................................................................................... 36

4.5.2 粉煤灰再生混凝土抗压强度.................................................................... 37

4.5.3 硅灰再生混凝土抗压强度........................................................................ 38

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摘要：

摘要由于天然骨料的来源广泛和价格低廉，人们对其的滥采滥用造成了严重的资源枯竭和环境污染。另外，建筑的更新和市政动迁规模的不断加大会产生大量的废弃混凝土，如不能妥善处置，不仅会侵占大量耕地还会污染环境。再生混凝土应运而生，再生混凝土是利用废弃混凝土，经过破碎，清洗，分级后，按照一定的比例混合形成骨料，以此部分或全部代替天然骨料配制的混凝土。国内外学者通过对再生混凝土的力学性能的研究，分析了其在实际工程中广泛应用的可能性。本文通过对大量不同粗骨料取代率，单掺粉煤灰、硅灰和复掺粉煤灰、硅灰的再生混凝土进行冻融循环试验，分析其力学性能及抗冻性能的变化，并建立了冻融循环后相关冻融损伤模型，主要开展的工作...

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