混凝土在相變高溫之下抗壓強度之研究

The research of concrete under Phase transition high temperature intensity

黃彥翔(Yen-Hsiang Huang)

指導教授 ： 吳傳威

國立臺北科技大學/工程學院/土木與防災研究所/碩士(2010年)

摘要

前期研究與文獻提出影響受火害之混凝土抗壓強度的重要因素包括最高溫與最高溫延時。另混凝土試體在573度，內部矽質骨材晶相轉變，SiO_2之結晶會由α相轉變為β相，混凝土抗壓強度在此階段會大幅度折減，且最高溫延時前兩小時為抗壓強度主要折減時段，並在延時120分鐘時，抗壓強度出現最小值。
本研究則更深入探討混凝土在高溫573度下之行為，及延時時間與強度折減的關係，實驗研究參數包括混凝土強度，試體尺寸及延時時間間距。研究結果顯示除了280(kgf/cm^2)強度試體在延時130分鐘出現最小值與過去研究所示較為相近之外，其他試體結果皆與文獻所述不浮。另由140(kgf/cm^2)試體之試驗顯示，經高溫延時之後強度折減與延時時間關係存在一特殊規律性，而延時時間越久，強度折減則確實越多。

關鍵字

相變

並列摘要

Earlier researches and literatures indicated that the factors of affecting the strength of concrete under fire harmed included the highest temperature, and the duration of the temperature. When the temperature of concrete reaches 573℃, the crystal phase of SiO2 would transfer from phase to phase, and the strength of the concrete would reduce a great amount. The first two hours of the highest temperature duration was the major reduction period, and the minimum strength would appear at duration 120 minutes.
The present study aimed at a more profound investigation of the behavior and the relation between time duration and the strength reduction of concrete under 573 ℃. The experiment parameters included the strength of concrete, the sizes of test cylinders, and the time duration. The results shown that besides the minimum strength of 280 kgf/cm2 appeared at duration 130 minutes coincided with the earlier research,

all the rest outcomes were different from the earlier statements. It is worth noting that there exists a special regular relation between the strength reduction of concrete and the time duration for 140 kgf/cm2 specimens. Nevertheless, the longer the duration of time under 573℃, the more reduction of concrete strength is clearly shown.

並列關鍵字

Phase transition

參考文獻

國立台北科技大學 工程科技研究所,台北(2010)

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