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Permeability of Concrete

Concrete Damage from Low pH Water

Description

Concrete damage from low pH water happens when acids react with the hydrated cement paste. This reaction dissolves the paste, so the concrete becomes softer and weaker. The problem is often seen in chimneys, sewers, and industrial settings.

The amount of damage depends on how acidic the water is....

Transcript

酸与混凝土相互作用会溶解水化水泥浆体,导致材料软化并结构强度降低。

当水的pH值降至6.5以下时,酸性会破坏混凝土;若pH值进一步降至4.5以下,劣化过程将加速。

含有15至60百万分率二氧化碳的水(例如融化的冰水)可降解混凝土。含有超过60百万分率二氧化碳的泥炭水具有高度腐蚀性。

生活污水虽然呈碱性,但在高温条件下,厌氧细菌会将硫化物转化为硫化氢,后者被好氧细菌氧化成硫酸,从而腐蚀下水道。

氢离子通过水泥凝胶的扩散速率也会影响侵蚀速率,尤其是在氢氧化钙已被溶解并冲刷掉之后。

通过稀释的硅酸钠稳定化可防止氢氧化钙的侵蚀,硅酸钠可在混凝土孔隙中形成硅酸钙。

采用煤焦油沥青、橡胶或沥青类涂料以及环氧树脂等表...

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