鹼－骨材反應為一長期的混凝土劣化問題。過去研究發現，台灣東部的海岸山脈所出產的安山岩存在此問題，並有現地案例佐證。然而過去研究與案例調查多著重在東部花蓮以南的海岸山脈及花東縱谷，在花蓮以北地區出產以變質岩為主的砂石則較少相關研究。本研究即針對宜蘭、花蓮地區各河川包含蘭陽溪、東澳溪、南澳溪、立霧溪、三棧溪、和平溪、花蓮溪、木瓜溪等河川所產砂石進行鹼反應評估與案例調查；另外並對和平溪骨材中幾種主要岩種，包含石英脈、片麻岩、綠色片岩、變質基性岩與大理岩等進行鹼反應性檢測試驗，以找出此區域反應性的主要岩種。研究結果發現，這些河川出產以變質岩為主的骨材均具有鹼反應性的潛能，並且相較於海岸山脈安山岩此類骨材的鹼反應性屬於晚期膨脹型，具有在低鹼量環境下即可發生鹼－骨材反應與長期仍持續膨脹的特性，在工程使用上應多加注意。 The Alkali-aggregate reaction (AAR) is a kind of concrete deleterious problem. From past investigations, it was found that rocks quarried from the east area of Taiwan could be highly reactive for the presence of affected concrete structures. Since the investigations were focused on Coast Mountains in south of Hualien and Hualien-drift valley,the aggregates composed of metamorphous rocks from north of Hualien are lacking of examinations. The AAR potential evaluations of aggregates were carried out by laboratory tests and site investigations. Besides, five kinds of major rocks in Her-ping river, including quartz vein, gneiss, green schist, metabasite, and marble, were also investigated to determine the primary affective mineral.The researches show that aggregates from metamorphic rocksfrom river basins in this area are regarded as high AAR potentials. Unlike the andesite from Coast Mountains area, these aggregates are classified as late-expansion type, and will be deleterious under low alkali content.Using these aggregates in constructions should be with cautions.
