本文以營建廢棄紅磚製成再生粗骨材取代不同比例天然粗骨材拌製再生混凝土，探討紅磚再生粗骨材對混凝土抗壓強度、超音波速值及高溫受熱後前述二項性質之影響。試驗結果顯示：再生粗骨材取代比例越高，抗壓強度、超音波速值越低；再生粗骨材之使用對晚期之抗壓強度影響不大，取代量越高，晚期強度提升幅度越大；高溫試驗結果顯示：加溫至 300℃可提升再生混凝土抗壓強度，高溫 440℃-800℃為再生混凝土抗壓強度及超音波速值下降主要區段，高溫作用後再生混凝土強度折減值較普通混凝土略小，折減率與普通混凝土相近，高溫作用後再生混凝土超音波速折減值、折減率較普通混凝土大。

The purpose of this paper is to investigate the effects on the property of recycled concrete with various percentages of coarse aggregate replaced by crushed construction brick. Compressive strength and ultrasonic pulse velocity of recycled concrete subjected to elevated temperatures are carried out in this study. Experiment results showed that the compressive strength and ultrasonic pulse velocity are decreased when more recycled aggregates are used. It appears to be an insignificant effect on the long-term strength of recycled concrete. The development of long-term compressive strength is increased as replacement level is increased. Experiment results revealed that the elevated temperature would enhance the compressive strength of recycled concrete at 300℃. In the range of 440-800℃, recycled concrete lost most of its original
compressive strength and ultrasonic pulse velocity. Compared to plain concrete, recycled concrete had a smaller reduction and similar discount rate of compressive strength and had a greater reduction and greater discount rate of ultrasonic pulse velocity after high temperatures exposure.