Increasing environmental awareness has shifted the focus on utilizing secondary/recycled material for constructional activities to reduce the onus on naturally available materials. MSW incinerated bottom ash (MSWI BA) is a by-product from waste-to-energy (WtE) facilities, and its properties vary depending on waste composition and the combustion process. Currently, the MSWI BA generated in India is dumped in an unscientific manner in landfills, and there are not many studies available in the country on the utilization potential of the ash. This paper investigates the physical and mechanical characteristics of MSWI BA for utilization in subgrades and sub-base courses in flexible pavements. Ash was collected from two WtE plants in Delhi, India. A comprehensive laboratory testing [grain size distribution, specific gravity, water absorption, modified proctor test (MPT), relative density, CBR test, Los Angeles abrasion test, and impact test] on minus 35 mm particle size was performed to evaluate the performance of the ash. MSWI BA is found to be porous, non-plastic, and well-graded silty sand with gravel-like material. Minimum and maximum dry densities obtained from the relative density test range from 12.4 to 15.3 kN/m3, indicating that it is lightweight compared to naturally available material. Maximum dry density observed from MPT (16.6–16.7 kN/m3) is more than that in the relative density test (15.1–15.3 kN/m3), and this may be attributed to the crushing of particles due to impact compaction in MPT, contrary to vibratory compaction in the relative density test. Crushing under impact loading is also evident from the impact test. Impact and abrasion values of 50–55% are more than maximum permissible value in standards, limiting its direct application in the sub-base course. CBR values of 52.7–59.6% indicate that the material will offer a higher bearing capacity to pavement layers. Based on the properties studied, MSWI BA seems favorable for subgrade application. However, its properties need to be improved for the sub-base course, possibly by blending with natural aggregate or cement.
Feasibility of Utilizing MSW Incinerated Bottom Ash for Subgrade and Sub-Base Applications in Flexible Pavements
Lecture Notes in Civil Engineering
Indian Geotechnical Conference ; 2021 ; Trichy, India December 16, 2021 - December 18, 2021
2022-12-11
9 pages
Article/Chapter (Book)
Electronic Resource
English
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