Microstructural investigations on the skinning of ultra-high performance concrete
Microstructural investigations on the skinning of ultra-high performance concrete
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DOI：
10.1016/j.cemconcomp.2014.11.010
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发表时间：
2015-03
影响因子：
10.5
通讯作者：
A. Wetzel;C. Glotzbach;Kasem Maryamh;B. Middendorf
中科院分区：
文献类型：
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作者：
A. Wetzel;C. Glotzbach;Kasem Maryamh;B. Middendorf
通过对超高性能混凝土（UHPC）表面微观结构的研究，分析了超高性能混凝土在最初几秒到几分钟内发生的结皮现象。低水含量和由此产生的高含量的超增塑剂，即聚羧酸酯醚，导致含硅灰的细粒UHPC的流变行为的差异。粘弹性表面层阻碍脱气并限制混凝土表面的平滑。详细的多方法表征的分层横截面的微观结构显示，在UHPC的表面上的聚羧酸醚高效减水剂（PCE）的富集。FITC染色的PCE进行了定位和相对定量。一个假设的形成的皮肤，包括PCE富集蒸发驱动的是来自这个微观结构的研究。
A skinning phenomenon occurring in the first seconds to minutes on ultra-high performance concrete (UHPC) was analysed by microstructural investigations. The low water content and the resulting high content of superplasticizers, i.e. polycarboxylate ethers, lead to differences in rheological behaviour of fine grained UHPC containing silica fume. A visco-elastic surface layer impedes the deaeration and constrains smoothing of the concrete surface. A detailed multi-method characterization of the microstructure of the layered cross-section revealed enrichments of polycarboxylate ether superplasticizers (PCE) on the surface of the UHPC. FITC-staining of the PCE made a localisation and relative quantification possible. A hypothesis for the formation of the skin comprising PCE enrichment driven by evaporation is derived from this microstructural study.