礦物摻料或以表面塗封材料保護之混凝土抗氯離子滲透性

Chloride Penetration Into Concrete Incorporating Mineral Admixtures or Protected with Surface Coating Material Under Chloride Environments

本文將對混凝土添加礦物摻料及以表面塗封材料於混凝土表面後，其在防止氯離子滲透之成效做一報吿。混凝土以高、中及低水灰比，添加及不添加礦物摻料，混凝土表面以塗封及不塗封等方式為試驗變數。鋼筋混凝土版試樣以濃度4%之氯化鈉溶液浸置其表面再於空氣中乾燥、反覆乾濕循環70次。混凝土內的氯離子測定分別於10，20，60及70次乾濕循環後進行。試驗結果顯示，混凝土添加礦物摻料能明顯的減少氯離子滲透。此外，良好耐久的表面塗封能幾乎完全防止氯離子滲入混凝土中。換言之，混凝土結構採用礦物摻料或以表面塗封材料加以保護，比一般混凝土暴露在氯離子的環境下，將有顯著的延長其使用壽命，又良好的表面塗封材料對使用壽命的延長比礦物摻料更為有效。

The effects of mineral admixtures and concrete surface coatings on the prevention of chloride intrusion into concrete is reported. Concrete of high, low and medium water to binder ratio, with and without mineral admixtures, or with and without a protected surface coating were designed. Reinforced concrete slab specimens were subjected up to 70 cycles of wetting and drying by ponding 4.0% sodium chloride solution and drying in atmospheric air. The chloride content in concrete was evaluated after 10, 20, 60 and 70 cycles of wetting and drying. The results show that the incorporation of mineral admixtures has a significant effect in reducing the chloride intrusion into concrete. As a result, it can be said that the service life of concrete structures incorporating mineral admixtures or protected with surface coating materials becomes significantly longer than that of the structures made of plain concretes when exposed to chloride environments, but, a good surface coating is far more effective and superior in enhancing service life than the incorporation of mineral admixtures.