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研究了采用掺合料浆液包覆处理老混凝土表面对新老混凝土界面微观结构与性能的影响,结果表明,与未经界面处理相比,采用质量浓度为20%的粉煤灰浆液处理的新老混凝土界面粘结试样3 d和28 d界面剪切强度可提高45.1%和18.2%,经20%矿渣浆液界面处理试样各龄期界面剪切强度分别提高达74.2%和69.2%。扫描电镜分析表明,未经界面处理试样老混凝土表面孔隙和新老混凝土界面处存在CH富集现象,而经粉煤灰和矿渣掺合料浆液包覆处理后,在老混凝土表面及孔隙中吸附的微细掺合料粒子,可吸收在新老混凝土界面区和老混凝土表面孔隙中富集的CH,在老混凝土表面孔隙中和新老混凝土界面处形成对界面粘结强度有贡献的水化产物,从而提高界面粘结强度。
The effect of the mixed concrete slurry on the microstructure and properties of the new-old concrete interface was studied. The results show that compared with the non-interfacial treatment, the new slurry treated with the fly ash slurry with the mass concentration of 20% The interfacial shear strength increased by 45.1% and 18.2% on 3 d and 28 d of the old concrete interfacial specimens. The interfacial shear strength increased by 74.2% and 69.2% at 20 and 20% respectively. Scanning electron microscopy analysis showed that there was CH enrichment phenomenon in the interface between the old concrete and the old concrete without interfacial treatment. After being coated with fly ash and slag admixture slurry, the surface of the old concrete and the pores Adsorbed finely divided admixture particles can absorb CH enriched in the pores of the old concrete interface and the old concrete, and form a hydration that contributes to the interfacial adhesion strength in the pores of the old concrete surface and the new-old concrete interface Product, thereby enhancing the interface bond strength.