改良轉爐石應用於底層之成效評估

The study in applicability of modified basic oxygen furnace slag used in the base course

黃煒翔(Wei-Siang Huang)

指導教授 ： 林登峰

共同指導教授 ： 羅煥琳(Huan-Lin Luo)

義守大學/理工學院/土木與生態工程學系/碩士(2014年)

https://doi.org/10.6343/ISU.2014.00296

摘要

本研究以改良轉爐石應用於底層評估其成效，分為現地試鋪及實驗室試驗兩部分進行。首先於實驗室進行轉爐石性質試驗試驗，包含夯實試驗、CBR、導電度等試驗，為尋求在不危害公程性質下最適材料配比。第二步驟是選擇一試驗場地進行現地試鋪，在施工前進行路基土壤檢測及施工後品質評估，並於追蹤路面平坦度及測量試驗，評估改良轉爐石路面成效。本研究一年現地檢測結果，路面平均高程差為16.10mm，而平坦度標準差值平均為2.92mm，符合交通部公路總局規範之要求。另外，改良轉爐石以CNS14602之級配要求夯打試體，且浸泡80 ± 3°C連續養治，其膨脹率僅為0.39%，遠低於CNS 14602 規範最終回脹率1.5%要求；而轉爐石以相同方法進行試驗，其膨脹率在2.932%，因此改良轉爐石確實能夠有效降低f-CaO，並抑制轉爐石回脹量。從電導度來探討膨脹量發現隨改良轉爐石及轉爐石取代量增加而電導度也隨之上升，顯示電導度越高膨脹率越高，而改良轉爐石各取代量電導度皆小於轉爐石。
本研究亦發現，隨著改良轉爐石取代量越多，其CBR值也隨之上升，且取代20%至100%皆大於規範要求，其中全取代量之CBR值高達182%(而轉爐石全取代量之CBR值在167%)，顯示改良轉爐石抗承載能力優於轉爐石，充分顯示改良轉爐石具有較高度結構穩定性，且改良轉爐石滲透係數高於轉爐石，能快速排水不受水份侵害膨脹，應可作為道路底層級配使用。從各項趨勢來看改良轉爐石全取代75%天然粗骨材，並不會造成路面膨脹危害，也有良好之抗承載能力，在工程應用上是可行的。

關鍵字

改良轉爐石 ； 電導度

並列摘要

In this study, the modified basic oxygen furnace (BOF) slag is applied to the base course of pavement. Test road and laboratory tests are carried out in the study. The laboratory tests including compact test, CBR, and conductivity testare performed to obtain the basic properties of BOF slag and the suitable amount of BOF slag mix ratio. Then, a site for the construction of test road is selected. Before the test road is constructed, the pavement subgrade soil is examined. After the completion of construction of test road, the assessment of pavement quality is carried out. To evaluate the effects of modified BOF slag on the pavement performance, the flatness and elevation differences of pavement are constantly measured. After one year of the measurement for the modified BOF slag pavement, the average elevation difference and standard deviation of pavement for test road are 16.10mm and 2.92mm, respectively, in which are met for the requirements set by the Directorate General of Highways, Ministry of Transportation and Communications, Taiwan. Moreover, according to the requirements of CNS 14602 standard, the expansion ratio for modified BOF slag specimens, in which cured in the water at temperature of 80 ± 3°C, obtained from compaction test is 0.39%. This ratio is smaller than that required by the CNS 14602 standard, 1.5%. The expansion ratio for regular BOF slag specimens is 2.932%. It indicates that the amount of f-CaO in modified BOF slag is effectively reduced. As a result, the swelling caused by the BOF slag is reduced. Furthermore, results obtained from conductivity tests show that the amount of swelling increases with the increase of conductivity for both modified and regular BOF slag. It suggests that the expansion ratios for both slags increase with the increase of the conductivity. However, the amount of swelling for modified BOF slag is less than that of the regular BOF slag.
In this study, the CBR values increase with the increasing amount of the modified BOF slag replacement. Moreover, the CBR values for the amounts of modified BOF slag replacement ranging from 20% to 100% are larger than that require by the standards. The CBR value is 182% for specimens with 100% modified BOF slag replacement; 167% for specimens with 100% regular BOF slag replacement. It indicates that pavement with the modified BOF slag replacement has better bearing capacity and structural stability than that of the regular BOF slag replacement. Furthermore, the permeability of the modified BOF slag is higher than that of the regular BOF slag. Hence, the modified BOF slag can be used as pavement base course material to help improve the drainage of the pavement. In this study, it suggests that, when applied as pavement base course materials, the amount of coarse aggregates replaced by the modified BOF slag can be up to 75%. The pavement would not be damaged by the expansion caused by slag and have good bearing capacity. It is feasible to apply this amount of modified BOF slag to the engineering application.

並列關鍵字

modified BOF slag ； conductivity

參考文獻

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