Abstract Experimental evidence of a smooth carbonation front is often used to support the inclusion of kinetic reactions in reactive transport models. A new interpretation for a smooth carbonation front is proposed. We first show that the alkalis and sulfur can be used to map a natural carbonation front with energy dispersive spectroscopy. The resulting carbonation front is relatively sharp but tortuous. Most experimental methods takes an average over a volume which smooths the front. To illustrate this new interpretation, we also present a new carbonation model. Instead of using kinetic rates, we obtain a wider apparent carbonation front by considering a distribution of gas diffusion coefficients. The simulated profiles are similar to the experimental ones. This work does not prove that we should get rid of kinetic rates. However it demonstrates that similar macroscopic results can be obtained with very different assumptions. Therefore, these mechanisms must be quantified independently.

中文翻译：

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天然碳酸水泥浆体中碳酸化前沿的特征长度：对反应输运模型的影响

摘要 平滑碳化前沿的实验证据通常用于支持将动力学反应包含在反应传输模型中。提出了对平滑碳化前沿的新解释。我们首先表明碱和硫可用于通过能量色散光谱绘制天然碳酸化前沿。由此产生的碳化前沿相对尖锐但曲折。大多数实验方法对平滑前部的体积取平均值。为了说明这种新解释，我们还提出了一个新的碳化模型。我们没有使用动力学速率，而是通过考虑气体扩散系数的分布来获得更宽的表观碳化前沿。模拟剖面与实验剖面相似。这项工作并不能证明我们应该摆脱动力学速率。然而，它表明可以使用非常不同的假设获得类似的宏观结果。因此，这些机制必须独立量化。