以廢棄紅磚取代細骨材對再生混凝土 性質影響之研究

Study on Recycled Concrete Using Construction Bricks as Fine Aggregates

廖譽勝(yu-sheng liao)

指導教授 ： 何仲明

中原大學/工學院/土木工程學系/碩士(2008年)

https://doi.org/10.6840/cycu200800463

摘要

摘 要
由於台灣主要的河川已禁止開採砂石，導致砂、石來源受到限制，因而造成砂、石價格飆升。每年產生大量的營建廢棄物，一來對環境造成污染及破壞，二來掩埋場所不易尋得，大量營建廢棄物或受外力所破壞之拆除廢棄物無處可放置。隨著環保意識抬頭，各國對於永續發展越來越重視。基於以上種種因素，將營建廢棄物中可用之混凝土塊、磚瓦處理成再生骨材是勢在必行。本文將廢棄紅磚處理成紅磚再生細骨材，以不同水灰比、取代量為變數，探討紅磚再生細骨材取代量對再生混凝土影響之研究。
試驗結果顯示以紅磚再生細骨材取代天然細骨材之再生混凝土，會增加卜作嵐反應，因紅磚含有大量二氧化矽及氧化鋁，此為卜作嵐材料，造成取代量越多抗壓強度提升越快，導致水灰比0.4組含紅磚再生細骨材之混凝土強度與未含紅磚再生細骨材之混凝土強度相距不到5%，甚至超過對照組之強度。紅磚再生細骨材取代量之不同對水灰比0.6組抗壓強度影響不大，在各齡期中含紅磚再生細骨材之混凝土與對照組至多相距20%，最少只差了0.7%。廢棄紅磚之高含粉量(12.43%)雖對水泥砂漿強度有所折減，但影響程度不大。水灰比0.4齡期28天時，取代量100%(低含粉量)之水泥砂漿抗壓強度約高於取代量100%(高含粉量)1.2%。水灰比0.6齡期28天時，取代量100%(低含粉量)100%之水泥砂漿抗壓強度約高於取代量100%(高含粉量)10%。

關鍵字

營建廢棄物 ； 卜作嵐反應 ； 超音波速 ； 再生骨材 ； 燒失量

並列摘要

Abstract
The government suspended the exploiting of sand and gravel in Taiwan's main streams. The difficulty of obtaining a stable supply of aggregates causes their prices to go up dramatically. On the other hand, huge amount of construction discards are produced every year, causing pollutions and destructions to the environment. Secondly, dumping grounds for construction discards are difficult to find. As environmental consciousness of people rises, every country begins to pay more and more attention to sustainable usage of materials. Due to the factors stated above, transferring construction wastes into reusable materials is a definite act. This research is to study the effect of using construction brick-sand to replace fine aggregates in recycled concrete.
Test results showed that using construction bricks as fine aggregates would enhance Pozzolan reaction, owing to the large proportion of SiO2 and Al2O3 contained in bricks. The Pozzolan effects were very obvious for concretes with water to cement ratio of 0.4: the compressive strength of recycled concrete with construction bricks as FA were closed to those with natural aggregates. For water ratio of 0.6, the reduction range is not very large, ranging from 0.7% to 20%. The crushed construction bricks had a very high percentage of dust (about 12%). The effect of brick dust on strength of concrete is studied by two groups of specimens: one with the 12% dust included and one with the dust washed away. For recycled concrete with water ratio of 0.4 and 100% replacement of brick sands, strength of specimen with dust is 1.2% higher than those without dust. However, for higher water cement ratio of 0.6, the strength is 10% higher.

並列關鍵字

recycled aggregates ； lost of ignition ； pozzolan reaction ； ultra sonic pulse velocity ； construction wastes

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