不同輕質骨材對輕質骨材混凝土之耐久性影響

Durability of Reinforced Lightweight Concrete Subject to Different Lightweight Aggregates

何政翰(Cheng-Han Ho)

指導教授 ： 李明君

朝陽科技大學/理工學院/營建工程系/碩士(2009年)

摘要

本研究針對『不同輕質骨材對輕質骨材混凝土之耐久性』進行探討評估，配比設計包括普通混凝土、兩種輕質骨材混凝土與輕質骨材透水混凝土，共四種混凝土配比，本期主要是針對輕質骨材混凝土之鋼筋腐蝕研究，鋼筋腐蝕惡化環境包括海水(鹽害)乾濕浸泡與二氧化碳加速碳化（中性化）反應二種，於上述環境下進行相關測試，包括（1）抗壓強度，（2）抗彎強度，（3）劈張強度，（4）碳化深度，（5）鋼筋腐蝕電位量檢測，（6）吸水率，（7）微觀（OM）分析。
研究結果顯示，使用比重較高輕質骨材之混凝土其強度與單位重較高，但輕質骨材混凝土單位重低於普通混凝土，在同一水灰比下，使用較高密度之輕質骨材混凝土強度可較接近普通混凝土強度。以二氧化碳加速中性化試驗中，混凝土會隨著時間的增加，使碳化深度有逐漸增加趨勢；經加速中性化240小時後，輕質骨材混凝土之碳化深度與普通混凝土差異不大：海水乾溼循環試驗中，鋼筋腐蝕電位值於20循環後皆低於-350mV，其腐蝕機率高於90％，而經海水乾溼20循環後之試體並未出現龜裂現象。

關鍵字

耐久性 ； 顆粒強度 ； 輕質骨材 ； 吸水性

並列摘要

In this research, the durability of reinforced lightweight concrete subject to different lightweight aggregates is investigated. Four mix design concretes included ordinary concrete, two lightweight aggregate concretes and pervious lightweight aggregate concrete. The project aims to run the steel corrosion test for the reinforced lightweight aggregate concrete in sea water dry-wet immersion and carbonization tests. The study will be tested and evaluated by the following items: compression strength, bending strength, splitting tensile strength, carbonated depth measurement, corrosion potential method, water absorption, optics microscopy examination.
The findings showed that the higher specific weight of lightweight aggregate concrete exhibit relatively high strength and unit weight. In the same water-cement ratio level, the strength of higher density of lightweight aggregate concrete would reach those of normal concrete.
At the accelerated carbonation test, the carbonation depth of concrete would increase with time and there is a gradual increase in carbonation depth trend. The carbonation depth of lightweight aggregate concrete specimens was the almost same as compared with those of normal concrete ones after 240 hours accelerated carbonation test. In dry-wet immersion by sea water test, reinforcement corrosion potential values were less than-350mV CSE after 20 cycles, the corrosion probability is higher than 90%. After 20 drying and wetting cycles of sea water immersion test, the cracking of concrete specimens does not appear.

並列關鍵字

Keywords：lightweight aggregate ； durability ； grain strength ； water-absorption

參考文獻

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【27】 Papadakis V. G., “Effect of Supplementary Cementing Materials on Concrete Resistance Against Carbonation and Chloride Ingress”, Cement and Concrete Research, Vol. 30, No. 2, pp. 291-299, 2000.

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