飛灰增進混凝土結構耐久性之研究

Improvement of Concrete Durability by Adding Fly Ash

國內混凝土因耐久性劣化而衍生的工程品質問題日趨嚴重，如「海砂屋」、「帽樑裂縫」……等。有鑑於此，本研究擬針對影響混凝土耐久性的重要基因，透過病理學優生理念，使得混凝土有較佳的「生命週期」，分析運用本土卜作嵐材料抑制混凝土受物化作用之病變與對策。結果顯示適當的運用飛灰可提昇混凝土的耐久性，降低氫氧化鈣（CH）含量，有效減少總孔隙量，減低滲透係數，具良好的防水性能。而孔隙結構緻密，使得飛灰水泥砂漿能抑制鹼－矽反應，消耗氫氧化鈣，減少硫酸鹽侵蝕，控制混凝土中鋼筋的腐蝕機率，並能提昇混凝土之晩期強度。

The quality of the local concrete structures is easily getting worse because of the durability problem; such as ''Sea-sand house'', ''Nut Beam Crack'' and so on. This research is to study the crucial material factors affecting to concrete durability based on the eugenic idea of pathology for improving structure life. The pozzolanic material used to control the problems caused by the chemical effect and its related strategy for better concrete will be discussed, too. The result indicates that proper usage of fly ash can improve the durability of concrete, decrease the CH content to minimize the total voids amount, lower permeability coefficient for better water-proof property. Furthermore, the dense structure of voids can help fly ash concrete control alkali reaction, consume CH and minimize the sulfate attack for less corrsoion possibility of steels used in concrete and for better ultimate strength, Therefore it is meaningfully needed for high performance concrete.