- 學位論文
在無對流影響下混凝土傳導研究
A Study On The Thermal Conduction Of Concrete Without The Effect Of Convection
摘要
本研究目的在探討混凝土內加鋼板阻斷混凝土之熱對流後其熱傳導性質。部份試驗以鋼板阻隔混凝土內之熱對流，並針對影響混凝土變數中的幾項變數來做試驗，即比較不同粗骨材含量、不同水灰比及不同鋼板位置對混凝土熱傳導係數及熱對流之影響。試驗變數包括粗骨材含量、水灰比及鋼板位置的改變。其中粗骨材含量變化有三種：正常用量、相對於正常用量增加20％、增加40％。而水灰比之變化有二種：w/c＝0.4、w/c＝0.5。以及試體之鋼板位置：離加熱面6cm，12cm，3、9cm，6、12cm處。試驗所使用之試體為15cm × 15cm × 24cm之長方形試體。以單面加熱方式進行熱傳導試驗，升溫速率為5℃/min，加熱溫度為常溫至爐溫800℃。以實驗量測之溫度配合Fourier熱傳導公式，可求得混凝土之熱傳導係數。 試驗結果顯示，在鋼板前之熱傳導係數，有安置鋼板的熱傳係數比沒有安置鋼板的熱傳係數大；鋼板後則為無安置鋼板的熱傳係數較大。且增加粗骨材含量會增加混凝土之熱傳導係數與未加鋼板之混凝土有相同之性質；而增加水灰比卻會降低其熱傳導係數亦與未加鋼板之趨勢同。
並列摘要
This study investigates the thermal conductivity of concrete with different proportions of coarse aggregates, water cement ratio and the position of Galvalume. There are three proportions of coarse aggregates: the standard content, 20% more than the standard and 40% more. There are also two water cement ratio of 0.4 and 0.5. The test specimen is a rectangular block of 15cm x 15cm x 24cm. The position of Galvalume plate is inserted at four locations: 3,9 centimeter, 6,12 centimeter, 6 centimeter, 12 centimeter. It is heated in a oven to 800℃ at an increase rate of 5℃/min. The coefficients of thermal conductivity of concrete can be found from the test results and Fourier thermal conductivity equation. Test results show that the coefficient of conductivity concrete with Galvalume plate is larger than that without Galvalume plate concrete in the compartment before the plate, but the coefficient of conductivity in the compartment after the plate is lower than that without any Galvalume plate. And the increase in coarse aggregate will increase the coefficient of conductivity. On the other hand, increasing the water cement ratio will decrease the coefficient of conductivity.