The rim zone of cement-based materials - Barrier or fast lane for chemical degradation?
The rim zone of cement-based materials - Barrier or fast lane for chemical degradation?
复制标题
水泥基材料的边缘地带——化学降解的屏障还是快车道？
DOI：
10.1016/j.cemconcomp.2016.10.009
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发表时间：
2016
影响因子：
10.5
通讯作者：
Jonas Kaltenbach and Andreas Gerdes
中科院分区：
文献类型：
--
作者：
Matthias Schwotzer;Katsuyuki Konno;Jonas Kaltenbach and Andreas Gerdes
复杂的水泥基系统的长期稳定性的评估模型需要劣化反应的机制的精确知识，特别是尊重永久暴露于水性环境。通常，对这些机制的见解是从长期调查中推导出来的。然而，这些化学反应在暴露于腐蚀性环境后立即开始，导致组成和结构的快速变化。因此，其边缘区的性质发生变化，从而影响水溶液中的传输过程。在实验室实验中，这些表面处理的水泥基材料暴露于不同的氯化物溶液的稳定性的影响进行了研究，作为时间和温度的函数。表面下的成分和结构变化的分析揭示了结晶覆盖层的耐化学性的作用。这些层通常被描述为保护屏障。然而，边缘区中的这些过程可加速化学降解，并随后降低水泥基材料对侵蚀性水性环境的弹性。
Sophisticated evaluation models for the long-term stability of cement-based systems demand a precise knowledge of the mechanisms of deterioration reactions, particularly respecting a permanent exposure to aqueous environments. Commonly, insights into these mechanisms are deduced from long-term investigations. However, these chemical reactions start immediately after exposure to aggressive environments causing rapid changes of composition and structure. Consequently, properties of its rim zone change, which affects transport processes in aqueous solutions. In laboratory experiments, the influence of these surface processes on the stability of cement-based materials exposed to different chloride solutions was studied as a function of time and temperature. Analysis of compositional and structural changes beneath the surface reveal the role of crystalline covering layers for chemical resistance. Such layers are often described as protective barriers. However, these processes in the rim zone can accelerate chemical degradation and subsequently reduce the resilience of the cement-based materials to aggressive aqueous environments.