纳米硅溶胶对废弃新拌混凝土再生性能影响的研究

王维成; 张道明; 方国祥; 张学元; 王悦

doi:10.13204/j.gyjzG22022406

纳米硅溶胶对废弃新拌混凝土再生性能影响的研究

doi: 10.13204/j.gyjzG22022406

1. 齐齐哈尔大学材料科学与工程学院, 黑龙江齐齐哈尔 161006;
2. 齐齐哈尔大学建筑与土木工程学院, 黑龙江齐齐哈尔 161006;
3. 诚邦生态环境股份有限公司, 杭州 310008

基金项目:

黑龙江省省属高等学校基本科研业务费科研项目(135309207)

黑龙江省省属高等学校基本科研业务费青年创新人才项目(135509213)。

详细信息

作者简介:
王维成,男,1995年出生,硕士研究生。

通讯作者:
张道明,zdmzdm@sina.com。

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出版历程
- 收稿日期: 2022-02-22

Research on Effect of Nano-Silica on the Recyling Performance of Waste Fresh Concrete

1. College of Material Science and Engineering, Qiqihar University, Qiqihar 161006, China;
2. College of Architecture and Civil Engineering, Qiqihar University, Qiqihar 161006, China;
3. Chengbang Ecological Environment Co., Ltd., Hangzhou 310008, China

摘要

摘要: 针对因放置时间过长导致无法使用的废弃新拌混凝土,通过测试不同放置时间对废弃新拌混凝土性能的影响,综合考虑选定最优放置时间(120 min),并按30%取代率取代新拌混凝土直接制备再生新拌混凝土。同时,测试不同纳米硅溶胶掺量对再生新拌混凝土力学性能和工作性能的影响,并对其微观性能与结构进行了分析。结果表明:纳米硅溶胶掺量为3%时,再生新拌混凝土28 d抗压强度及劈裂抗拉强度分别提升了45.6%、63.9%;XRD、SEM及EDS分析显示,碱性环境下可加快硅溶胶中硅酸析出,并与Ca²⁺反应生成大量C-S-H(I)型凝胶,促进C₃S、C₂S等熟料的水化反应,降低了Ca/Si,使水泥浆体与骨料间紧密联结,C-S-H凝胶填充了部分孔隙及裂缝,界面过渡区更加致密,再生新拌混凝土强度显著提升。
- 废弃新拌混凝土 /
- 纳米硅溶胶 /
- 再生新拌混凝土 /
- 力学性能 /
- 微观表征
Abstract: For the waste fresh concrete that cannot be used due to too long storage time, the optimal storage time (120 min) was selected comprehensively by testing the effect of storage time on the performance of waste fresh concrete, and fresh concrete was replaced at 30% replacement rate to directly prepare recycled fresh concrete. At the same time, the influence of different nano-silica content on the mechanical properties and working properties of recycled fresh concrete was tested, and its microstructure and structure were analyzed. The results showed that when the nano-silica content was 3%, the 28 d compressive strength and splitting tensile strength of recycled fresh concrete were increased by 45.6% and 63.9%; XRD, SEM and EDS analysis showed that the precipitation of H₂SiO₃ acid in the nano-silica could be accelerated in an alkaline environment, and a large amount of C-S-H gel (type I) gel could be formed by reacting with Ca²⁺, they could promote the hydration reaction of clinker such as C₃S and C₂S, reduce Ca/Si and make cement paste and aggregate closely connected, C-S-H gel filled some pores and cracks, the interface transition zone was more compact, and the strength of recycled fresh concrete was significantly improved.
- waste fresh concrete /
- nano-silica /
- recycled fresh concrete /
- mechanical properties /
- microstructure

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