纳米硅溶胶对再生骨料混凝土力学性能影响及微观机理研究  

Effect of nano-silica on mechanical properties and microstructure of recycled aggregate concrete

作　　者：王维成 邵鹏飞 胡永超 张道明 张学元 王悦 WANG Wei-cheng;SHAO Peng-fei;HU Yong-chao;ZHANG Dao-ming;ZHANG Xue-yuan;WANG Yue(School of Material Science and Engineering,Qiqihar University,Heilongjiang Qiqihar 161006,China;Chengbang Ecological Environment Co.,Ltd.,Hangzhou 310008,China;School of Architecture and Civil Engineering,Qiqihar University,Heilongjiang Qiqihar 161006,China)

机构地区：[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]诚邦生态环境股份有限公司,杭州310008 [3]齐齐哈尔大学建筑与土木工程学院,黑龙江齐齐哈尔161006

出　　处：《齐齐哈尔大学学报（自然科学版）》2023年第3期68-73,共6页Journal of Qiqihar University(Natural Science Edition)

基　　金：齐齐哈尔大学横向课题“辅助胶凝材料对废弃混凝土再生性能影响的研究”(220122222019);黑龙江省高等教育教学改革一般项目“第二课堂课程思政沉浸式教学模式研究”(SJGY20210965)。

摘　　要：针对再生骨料孔隙率、吸水率、压碎指标均高于天然骨料,导致其制备的再生骨料混凝土力学性能劣化无法广泛应用的问题,采用“预先浸泡+拌和掺入”的双重改性方式对再生骨料混凝土进行改性处理,并对预先浸泡纳米硅溶胶的再生骨料的物理性能以及双重改性后的再生骨料混凝土的力学性能进行测试分析,利用SEM、EDS对改性的再生骨料混凝土进行微观表征。结果表明,纳米硅溶胶浓度为2%时,再生骨料的物理性能提升幅度最大且成本最低;纳米硅溶胶掺量为3%时,再生骨料混凝土28 d抗压强度及劈裂抗拉强度分别提升了42.4%、66.3%;SEM及EDS表征显示掺入纳米硅溶胶可加快水化反应,降低了Ca/Si,并生成大量C-S-H(I)型凝胶,使新旧水泥浆体以及浆体与骨料间紧密联结,再生骨料混凝土强度得到显著提升。As the porosity,water absorption and crushing indexes of recycled aggregate are higher than those of natural aggregate,the mechanical properties of recycled aggregate concrete prepared by recycled aggregate deteriorate and cannot be widely applied.In this study,the double modification method of"pre-soaking+mixing and incorporation"was adopted to modify reclaimed aggregate concrete,and the physical properties of recycled aggregate soaked in nano-silica in advance and the mechanical properties of recycled aggregate concrete after double modification were tested and analyzed,finally,SEM and EDS were used to characterize the modified recycled aggregate concrete.The results show that when the concentration of nano-silica is 2%,the physical properties of recycled aggregate are improved the most and the cost is the lowest;when the content of nano-silica is 3%,the 28 d compressive strength and splitting tensile strength of recycled aggregate concrete are increased by 42.4%and 66.3%;SEM and EDS showed that the incorporation of nano-silica could accelerate the hydration reaction,reduce Ca/Si and generate a large amount of C-S-H(I)gel,the new cement paste and the slurry and aggregate are closely connected,and the strength of recycled aggregate concrete is significantly improved.

关 键 词：再生骨料混凝土 纳米硅溶胶 力学性能 微观表征 

分 类 号：TU528[建筑科学—建筑技术科学]