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Open-cast coal mining operations generate a significant amount of waste materials, including rock. Typically, these materials are disposed of on valuable land without being used in environmentally friendly construction practices. Despite this, they are a viable alternative source of ingredients for concrete production. The construction industry is causing the depletion of natural resources and environmental degradation by producing an excessive amount of coarse aggregates for concrete production. In this context, the utilization of hard rock from coal mine overburden dumps (CMOD) is considered as a substitute for conventional coarse aggregates to address the issues of resource depletion, given its ready availability. However, aggregates obtained from CMOD are often porous and cracked, resulting in weak mechanical properties. To address these limitations, the aggregates were treated through cleaning and impregnation with a homogeneous silica fume solution and prepared M35 grade concrete along with two-stage mixing approach (TSMA). In this research, coarse aggregates made from hard rock of coal mine overburden dumps were used for the production of concrete to replace 100% conventional aggregates. When 100% CMOD-A is used and mixed by normal mixing approach as well as two-stage mixing approach, the bond strength is reduced by 9% and 6.5%, respectively, and in contrast, the compressive strength decreases by 5.04% and 4.68% at 7 days and 5.0% and 4.6% at 28 days, respectively, whereas the tensile strength decreased by 9.46% and 6.8% after 28 days. The morphological examination reveals the reason for the enhancement of the interfacial transition zone (ITZ) and its properties, resulting from the adoption of the suggested mixing strategy and impregnation of silica fume. The results demonstrate that conventional coarse aggregates can be successfully replaced with readily available aggregates obtained from CMOD to produce concrete with satisfactory workability and compressive strength and bond behavior compared to conventional concrete.

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Experimental Investigation on Mechanical Properties of Concrete Containing Treated Coarse Aggregates Obtained from Hard Rock of Open Coal Mine Dump

  • 会议论文

  • 发表日期：

    2025年

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  • Mustaque Ansari,
  • N. Kisku,
  • P. Gopinathan,
  • M. S. Santosh

摘要

Open-cast coal mining operations generate a significant amount of waste materials, including rock. Typically, these materials are disposed of on valuable land without being used in environmentally friendly construction practices. Despite this, they are a viable alternative source of ingredients for concrete production. The construction industry is causing the depletion of natural resources and environmental degradation by producing an excessive amount of coarse aggregates for concrete production. In this context, the utilization of hard rock from coal mine overburden dumps (CMOD) is considered as a substitute for conventional coarse aggregates to address the issues of resource depletion, given its ready availability. However, aggregates obtained from CMOD are often porous and cracked, resulting in weak mechanical properties. To address these limitations, the aggregates were treated through cleaning and impregnation with a homogeneous silica fume solution and prepared M35 grade concrete along with two-stage mixing approach (TSMA). In this research, coarse aggregates made from hard rock of coal mine overburden dumps were used for the production of concrete to replace 100% conventional aggregates. When 100% CMOD-A is used and mixed by normal mixing approach as well as two-stage mixing approach, the bond strength is reduced by 9% and 6.5%, respectively, and in contrast, the compressive strength decreases by 5.04% and 4.68% at 7 days and 5.0% and 4.6% at 28 days, respectively, whereas the tensile strength decreased by 9.46% and 6.8% after 28 days. The morphological examination reveals the reason for the enhancement of the interfacial transition zone (ITZ) and its properties, resulting from the adoption of the suggested mixing strategy and impregnation of silica fume. The results demonstrate that conventional coarse aggregates can be successfully replaced with readily available aggregates obtained from CMOD to produce concrete with satisfactory workability and compressive strength and bond behavior compared to conventional concrete.