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<p>Medical waste incineration ash (MWIA) is an increasingly important solid-waste residue, yet it is often disposed of without stabilization, creating potential environmental risks. This study evaluates the feasibility of using the MWIA investigated here as a partial cement replacement (0–40% by mass, at 10% intervals) in three concrete grades (M25, M30, and M35). MWIA was collected from the CCC incinerator under lower temperature (600–700°C), oven-dried, ground, and sieved to &lt;75 μm. Mechanical performance was assessed using Compressive and Splitting Tensile Strengths at 7, 28, and 56 days, while durability-related properties were evaluated using Ultrasonic Pulse Velocity (UPV), Fresh Density, Water Absorption, Void Content, and Rapid Chloride Permeability Test (RCPT). Environmental safety was assessed through total heavy-metal inventory by aqua regia digestion, semi-dynamic tank leaching of stabilized mortar and pH-controlled batch leaching of raw ash and demolished mortar. XRF showed that the MWIA investigated in this study is CaO-rich (CaO 40.25%) with an oxide sum of SiO<sub>2</sub>, Al<sub>2</sub>O<sub>3</sub> and Fe<sub>2</sub>O<sub>3</sub> slightly below the ASTM C618 criteria for conventional pozzolans. Across all grades, 10% MWIA provided the most balanced performance: at 56 days, strength recovered to approximately 95–98% of the control mixes. The average 56-day to 28-day strength gain ratio was also highest at 10% MWIA, with a value of 1.218. UPV remained above 3500 m/s, and the RCPT charge passed decreased by approximately 4.82–14.46% relative to the OPC mixes for different grades. Replacement levels of ≥20% produced persistent strength reductions and increased porosity-related indicators. Leaching results showed that cement-based stabilization greatly reduced heavy metal release. The cumulative leached fraction remained below 2% of the total metal inventory at 10% replacement and stayed within about 3-6% even at 40% replacement. These results suggest that low-dose MWIA use can be a practical option under controlled processing and curing conditions. Microstructural confirmation of the underlying hydration and immobilization mechanisms remains a priority for future work.</p>

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Performance assessment of medical waste incineration ash as partial cement replacement in concrete: Bangladesh perspective

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2026年5月5日

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  • Md. Shah Alam Sarker,
  • Salman Mahamud,
  • Pial Barua,
  • Abhi Chowdhury,
  • Md. Jillur Rahman,
  • Md. Abdus Shabur,
  • Md. Saiful Islam,
  • Md. Moinul Islam

摘要

Medical waste incineration ash (MWIA) is an increasingly important solid-waste residue, yet it is often disposed of without stabilization, creating potential environmental risks. This study evaluates the feasibility of using the MWIA investigated here as a partial cement replacement (0–40% by mass, at 10% intervals) in three concrete grades (M25, M30, and M35). MWIA was collected from the CCC incinerator under lower temperature (600–700°C), oven-dried, ground, and sieved to <75 μm. Mechanical performance was assessed using Compressive and Splitting Tensile Strengths at 7, 28, and 56 days, while durability-related properties were evaluated using Ultrasonic Pulse Velocity (UPV), Fresh Density, Water Absorption, Void Content, and Rapid Chloride Permeability Test (RCPT). Environmental safety was assessed through total heavy-metal inventory by aqua regia digestion, semi-dynamic tank leaching of stabilized mortar and pH-controlled batch leaching of raw ash and demolished mortar. XRF showed that the MWIA investigated in this study is CaO-rich (CaO 40.25%) with an oxide sum of SiO2, Al2O3 and Fe2O3 slightly below the ASTM C618 criteria for conventional pozzolans. Across all grades, 10% MWIA provided the most balanced performance: at 56 days, strength recovered to approximately 95–98% of the control mixes. The average 56-day to 28-day strength gain ratio was also highest at 10% MWIA, with a value of 1.218. UPV remained above 3500 m/s, and the RCPT charge passed decreased by approximately 4.82–14.46% relative to the OPC mixes for different grades. Replacement levels of ≥20% produced persistent strength reductions and increased porosity-related indicators. Leaching results showed that cement-based stabilization greatly reduced heavy metal release. The cumulative leached fraction remained below 2% of the total metal inventory at 10% replacement and stayed within about 3-6% even at 40% replacement. These results suggest that low-dose MWIA use can be a practical option under controlled processing and curing conditions. Microstructural confirmation of the underlying hydration and immobilization mechanisms remains a priority for future work.