邹定华,张艺升,肖路通,等. 烷基硅烷改性辅助胶凝材料对超高性能混凝土工作性能和力学性能的影响 [J].河南理工大学学报(自然科学版)，doi:10.16186/j.cnki.1673-9787.2024070028.

ZOU D H, ZHANG Y S, XIAO L T, et al． Effect of supplementary cementitious materials modified by short chain alkyl-silane on workability and mechanical properties of ultra-high-performance concrete[J]. Journal of Henan Polytechnic University(Natural Science)， doi: 10.16186/j.cnki.1673-9787. 2024070028.

烷基硅烷改性辅助胶凝材料对超高性能混凝土工作性能和力学性能的影响(网络首发)

邹定华¹，张艺升^1，2，肖路通¹，娄广辉³，张海波¹，祝瑜¹

1. 河南理工大学 材料科学与工程学院, 河南 焦作 454003；2. 河南省科学院，河南 郑州 450046；3. 河南建筑材料研究设计院有限责任公司，河南 郑州 450002

摘要: 目的 本研究探讨了使用短链烷基硅烷修饰辅助胶凝材料（SCMs）以提高超高性能混凝土（UHPC）工作性能的可行性。方法 研究中用丙基三乙氧基硅烷（PTOS）和辛基三乙氧基硅烷（TEOS）对硅灰和粉煤灰进行改性。测试了掺未改性和改性辅助胶凝材料UHPC的坍落扩展度及扩展至400mm所需的时间T₄₀₀。此外，通过测试水化热、非蒸发水含量以及抗压和抗折强度，分析改性后的辅助胶凝材料的火山灰反应及其对UHPC各项性能的影响。结果 研究结果表明，掺入改性SCMs后，UHPC的工作性能显著提高，且PTOS修饰的SCMs相较于TEOS修饰的SCMs具有更好的改善效果。硅烷的疏水性在1d和3d龄期时抑制了SCMs的火山灰反应，这种抑制作用延迟并降低了改性UHPC的水化热峰，使得掺入硅烷改性硅灰的UHPC早期强度和水化产物量均有所下降。但是硅烷改性粉煤灰对UHPC早期水化放热和水化产物生成的影响较小。此外，PTOS加速了3d后水化产物的生成，提高了改性UHPC在3d之后的强度，28d龄期时，掺入PTOS改性SCMs的UHPC强度与对照组UHPC的强度相当。而掺有TEOS改性SCMs的UHPC水化产物数量及强度低于对照组。结论 烷基硅烷改性SCMs显著提升了新拌UHPC的工作性能，混凝土的扩展度显著增大，早期强度略有影响。但硅烷有助于促进后期水化产物的形成，28d龄期时掺PTOS改性SCMs的UHPC水化产物量及强度与对照组相当。

关键词: 超高性能混凝土；辅助胶凝材料；烷基硅烷；表面改性；工作性能；强度

doi: 10.16186/j.cnki.1673-9787.2024070028

基金项目: 河南省科技攻关项目(232102320194);国家自然科学基金资助项目(52279132)

收稿日期：2024-07-08

修回日期：2024-10-09

网络首发日期：2024-12-25

Effect of supplementary cementitious materials modified by short chain alkyl-silane on workability and mechanical properties of ultra-high-performance concrete (Online)

ZOU Dinghua¹_, ZHANG Yisheng^1,2, XIAO Lutong¹, LOU Guanghui³, ZHANG Haibo¹, ZHU Yu¹

1.School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo 454003, Henan ,China；2.Henan Academy of Sciences，Zhengzhou 450046, Henan ,China；3.Henan Building Materials Research and Design Institute Co., Ltd, Zhengzhou 450002, Henan ,China

Abstract: Objectives The research presented in this paper aims to survey the feasibility of improving the workability of ultra-high-performance concrete (UHPC) using supplementary cementitious materials (SCMs) modified by alkyl-silane with short carbon chain. Propyltriethoxysilane (PTOS) and triethoxyoctylsilane (TEOS), with carbon chain containing 3 and 8 carbon atoms, respectively, were adopted. Methods Silica fume and fly ash were modified for UHPC preparation. Slump flow and T₄₀₀, the time for fresh concrete spreading up to 400 mm, of UHPC slurry with and without silane modified SCMs were measured. Effects of the modification on pozzolanic reaction of SCMs and mechanical properties of UHPC were also investigated.  Results The experiment results demonstrated that the workability of UHPC slurry was promoted evidently by PTOS and TEOS modified SCMs. Moreover, the SCMs modified by PTOS showed higher effect than those modified by TEOS. However, the hydrophobicity of the silanes inhibited the pozzolanic reaction of SCMs at 1 and 3 days. This postponed and lowered the main hydration heat peak of UHPC pastes. The amount of the hydration products and the strengths of the UHPC with silanes modified silica fume at 1 and 3 days were decreased thereby. A less impact on main hydration heat peak and amount of the hydration products of UHPC pastes with silanes modified fly ash and plain silica fume was observed at 1 and 3 days. The reduction of the strengths was also lower. The acceleration effect of the POTS facilitated the precipitation of the hydration products after 3 days. The strengths of the UHPC with PTOS modified SCMs were comparable to that of the plain one at 28 days. The higher hydrophobicity of TEOS due to its longer carbon chain enhanced the inhibitory effect on pozzolanic reaction of SCMs, which reduced the amount of the hydration products and strengths of UHPC at 28 days. Conclusions Silica fume and fly ash modified by alkyl silanes with short carbon chain improve the workability of UHPC slurry but had a slight impact on early strength. Silanes facilitate the precipitation of the hydration products at later age. At 28 days, the amount of hydration products and strength of UHPC with PTOS modified SCMs were comparable to that of the plain one..

Key words: Ultra-high-performance concrete (UHPC); Supplementary cementitious materials (SCMs); Alkyl silane; Surface modification; Workability; Strength