Assessment of slag incorporation in cold recycled mixtures emulsified asphalt: Mechanical performance and environmental impact
Recycled Asphalt Pavement (RAP) has been used for several decades. RAP material varies and can include limestone, granite, gravel, and sometimes recycled materials like slag. In Taiwan, RAP is mostly used in base courses as Cold Recycled Mixtures Emulsified Asphalt (CRME). However, the use of slag i...
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| Format: | Article |
| Language: | English |
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Elsevier
2025-07-01
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| Series: | Case Studies in Construction Materials |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2214509525000944 |
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| author | Putri Adhitana Paramitha Shih-Huang Chen Emil Adly Handy Prasetyo Wei-Lun Tsai |
| author_facet | Putri Adhitana Paramitha Shih-Huang Chen Emil Adly Handy Prasetyo Wei-Lun Tsai |
| author_sort | Putri Adhitana Paramitha |
| collection | DOAJ |
| description | Recycled Asphalt Pavement (RAP) has been used for several decades. RAP material varies and can include limestone, granite, gravel, and sometimes recycled materials like slag. In Taiwan, RAP is mostly used in base courses as Cold Recycled Mixtures Emulsified Asphalt (CRME). However, the use of slag in base courses is prohibited in Taiwan due to its potential for leaching and expansion properties. Unfortunately, RAP containing slag may occasionally be inadvertently introduced into CRME. This research proposes incorporating slag as aggregate in CRME, analyzing its mechanical properties and environmental effects to simulate the potential consequences when slag is unintentionally introduced into CRME. Three types of slag—Basic Oxygen Furnace slag (BOFs), Electric Arc Furnace slag (EAFs), and Incinerator Bottom Ash (IBA)—were added to the mixture at a percentage of 15 %, reflecting the possible inclusion of slag in CRME. Emulsified asphalt was used as a binder. The optimum contents of emulsified asphalt, cement, and water were determined before performance testing. Laboratory tests included indirect tensile strength (ITS), tensile strength ratio (TSR), and static creep tests. The environmental impact was assessed using the Toxicity Characteristic Leaching Procedure (TCLP) and volume expansion tests. The results of the mechanical tests showed that BOFs and EAFs mixtures provided higher strength, improved resistance to moisture damage, and better resistance to permanent deformation. In the TCLP test, all materials exhibited concentrations of specified heavy metals below the standard limits. The results of the expansion stability test showed that all materials expanded by less than 0.5 % at seven days, which meets the required limit. The study concludes that a 15 % addition of slag for cold recycled mixtures positively impacts mechanical properties and the absence of environmental impacts and volume expansion stability issues. Despite the above, pavement engineers should prioritize further studies on the long-term effects of slag addition on the environment and mechanical performance. |
| format | Article |
| id | doaj-art-9adf25cea38f4db2a4c3c6c68c09676d |
| institution | Kabale University |
| issn | 2214-5095 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Case Studies in Construction Materials |
| spelling | doaj-art-9adf25cea38f4db2a4c3c6c68c09676d2025-01-31T05:11:19ZengElsevierCase Studies in Construction Materials2214-50952025-07-0122e04295Assessment of slag incorporation in cold recycled mixtures emulsified asphalt: Mechanical performance and environmental impactPutri Adhitana Paramitha0Shih-Huang Chen1Emil Adly2Handy Prasetyo3Wei-Lun Tsai4Department of Civil Engineering, National Central University, No. 300, Zhongda Road, Zhongli, Taoyuan 320317, TaiwanDepartment of Civil Engineering, National Central University, No. 300, Zhongda Road, Zhongli, Taoyuan 320317, Taiwan; Corresponding author.Department of Civil Engineering, National Central University, No. 300, Zhongda Road, Zhongli, Taoyuan 320317, Taiwan; Department of Civil Engineering, Universitas Muhammadiyah Yogyakarta, Jl. Brawijaya, Kasihan, Bantul, Yogyakarta 55183, IndonesiaDepartment of Civil Engineering, National Central University, No. 300, Zhongda Road, Zhongli, Taoyuan 320317, TaiwanDepartment of Civil Engineering, National Central University, No. 300, Zhongda Road, Zhongli, Taoyuan 320317, TaiwanRecycled Asphalt Pavement (RAP) has been used for several decades. RAP material varies and can include limestone, granite, gravel, and sometimes recycled materials like slag. In Taiwan, RAP is mostly used in base courses as Cold Recycled Mixtures Emulsified Asphalt (CRME). However, the use of slag in base courses is prohibited in Taiwan due to its potential for leaching and expansion properties. Unfortunately, RAP containing slag may occasionally be inadvertently introduced into CRME. This research proposes incorporating slag as aggregate in CRME, analyzing its mechanical properties and environmental effects to simulate the potential consequences when slag is unintentionally introduced into CRME. Three types of slag—Basic Oxygen Furnace slag (BOFs), Electric Arc Furnace slag (EAFs), and Incinerator Bottom Ash (IBA)—were added to the mixture at a percentage of 15 %, reflecting the possible inclusion of slag in CRME. Emulsified asphalt was used as a binder. The optimum contents of emulsified asphalt, cement, and water were determined before performance testing. Laboratory tests included indirect tensile strength (ITS), tensile strength ratio (TSR), and static creep tests. The environmental impact was assessed using the Toxicity Characteristic Leaching Procedure (TCLP) and volume expansion tests. The results of the mechanical tests showed that BOFs and EAFs mixtures provided higher strength, improved resistance to moisture damage, and better resistance to permanent deformation. In the TCLP test, all materials exhibited concentrations of specified heavy metals below the standard limits. The results of the expansion stability test showed that all materials expanded by less than 0.5 % at seven days, which meets the required limit. The study concludes that a 15 % addition of slag for cold recycled mixtures positively impacts mechanical properties and the absence of environmental impacts and volume expansion stability issues. Despite the above, pavement engineers should prioritize further studies on the long-term effects of slag addition on the environment and mechanical performance.http://www.sciencedirect.com/science/article/pii/S2214509525000944Cold mixEmulsionRAPSlag |
| spellingShingle | Putri Adhitana Paramitha Shih-Huang Chen Emil Adly Handy Prasetyo Wei-Lun Tsai Assessment of slag incorporation in cold recycled mixtures emulsified asphalt: Mechanical performance and environmental impact Case Studies in Construction Materials Cold mix Emulsion RAP Slag |
| title | Assessment of slag incorporation in cold recycled mixtures emulsified asphalt: Mechanical performance and environmental impact |
| title_full | Assessment of slag incorporation in cold recycled mixtures emulsified asphalt: Mechanical performance and environmental impact |
| title_fullStr | Assessment of slag incorporation in cold recycled mixtures emulsified asphalt: Mechanical performance and environmental impact |
| title_full_unstemmed | Assessment of slag incorporation in cold recycled mixtures emulsified asphalt: Mechanical performance and environmental impact |
| title_short | Assessment of slag incorporation in cold recycled mixtures emulsified asphalt: Mechanical performance and environmental impact |
| title_sort | assessment of slag incorporation in cold recycled mixtures emulsified asphalt mechanical performance and environmental impact |
| topic | Cold mix Emulsion RAP Slag |
| url | http://www.sciencedirect.com/science/article/pii/S2214509525000944 |
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