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<p>The construction industry significantly contributes to energy consumption, resource depletion, and CO₂ emissions. To reduce its environmental impact and promote sustainability, the industry is increasingly shifting away from the use of ordinary portland cement (OPC) and natural materials, opting instead for alternative materials. Supplementary cementitious materials (SCMs), which may include organic or industrial waste, have become essential components in concrete mix design. This study investigates sugarcane bagasse ash (SBA) and rice husk ash (RHA), two agro-industrial waste materials typically disposed of in landfills, leading to environmental pollution and potential health risks. Utilizing these agricultural wastes in the construction sector underscores the sustainability of incorporating recycled materials into concrete production. Concrete strength is critical when using agro-industrial waste, and this study measures it using both destructive and non-destructive testing (NDT) methods. Among the NDT techniques, ultrasonic pulse velocity (UPV) and rebound hammer (RH) tests are more frequently used than others, such as windsor probes and core cutters, for assessing concrete strength. UPV and RH tests are widely recognized as reliable alternatives to destructive testing. While extensive research has been conducted on conventional concrete, there remains a lack of comprehensive data on sustainable concrete incorporating agro-industrial waste. This study aims to assess the performance of such sustainable concrete, focusing on the effects of partial OPC replacement with SBA and RHA, as evaluated through RH and UPV testing. OPC was partially replaced with RHA and SBA at intervals of 5%, ranging from 0% (control mix) to 30%. Additionally, the combined use of SBA and RHA was studied by maintaining a constant total replacement level of 30%, starting with 30% SBA and 0% RHA (i.e., 70% OPC), then progressively increasing RHA by 5% while decreasing SBA by 5%. The river sand was entirely replaced with manufactured sand (M-sand). The results indicate a 37% average reduction in workability compared to the control mix, which can be attributed to the porous and irregular nature of SBA and RHA particles. In terms of compressive strength, all mixes showed a decrease compared to the control, except for C95S5 and C95R5, which exhibited increases of 7.5% and 2%, respectively. A similar trend was observed in the NDT results. When a portion of OPC is replaced with SBA and RHA, the rebound hammer test indicates a continued decrease in compressive strength. However, the UPV results for C95S5, C95R5, C70S5R25 and C70S30 fall within the "excellent" quality category. This study provides guidelines for optimizing mix designs and quality control protocols for sustainable concrete structures. Incorporating SBA and RHA as partial substitutes for OPC in concrete manufacturing can significantly reduce environmental impact by lowering CO₂ emissions and promoting the reuse of agro-waste, while also contributing to cost-effective and sustainable construction practices.</p>

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Strength evaluation of concrete incorporating agro-industrial waste and M-sand using non-destructive testing

  • 期刊论文

  • 发表日期：

    2025年7月26日

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  • Pavan A. Nadgouda,
  • Anil Kumar Sharma

摘要

The construction industry significantly contributes to energy consumption, resource depletion, and CO₂ emissions. To reduce its environmental impact and promote sustainability, the industry is increasingly shifting away from the use of ordinary portland cement (OPC) and natural materials, opting instead for alternative materials. Supplementary cementitious materials (SCMs), which may include organic or industrial waste, have become essential components in concrete mix design. This study investigates sugarcane bagasse ash (SBA) and rice husk ash (RHA), two agro-industrial waste materials typically disposed of in landfills, leading to environmental pollution and potential health risks. Utilizing these agricultural wastes in the construction sector underscores the sustainability of incorporating recycled materials into concrete production. Concrete strength is critical when using agro-industrial waste, and this study measures it using both destructive and non-destructive testing (NDT) methods. Among the NDT techniques, ultrasonic pulse velocity (UPV) and rebound hammer (RH) tests are more frequently used than others, such as windsor probes and core cutters, for assessing concrete strength. UPV and RH tests are widely recognized as reliable alternatives to destructive testing. While extensive research has been conducted on conventional concrete, there remains a lack of comprehensive data on sustainable concrete incorporating agro-industrial waste. This study aims to assess the performance of such sustainable concrete, focusing on the effects of partial OPC replacement with SBA and RHA, as evaluated through RH and UPV testing. OPC was partially replaced with RHA and SBA at intervals of 5%, ranging from 0% (control mix) to 30%. Additionally, the combined use of SBA and RHA was studied by maintaining a constant total replacement level of 30%, starting with 30% SBA and 0% RHA (i.e., 70% OPC), then progressively increasing RHA by 5% while decreasing SBA by 5%. The river sand was entirely replaced with manufactured sand (M-sand). The results indicate a 37% average reduction in workability compared to the control mix, which can be attributed to the porous and irregular nature of SBA and RHA particles. In terms of compressive strength, all mixes showed a decrease compared to the control, except for C95S5 and C95R5, which exhibited increases of 7.5% and 2%, respectively. A similar trend was observed in the NDT results. When a portion of OPC is replaced with SBA and RHA, the rebound hammer test indicates a continued decrease in compressive strength. However, the UPV results for C95S5, C95R5, C70S5R25 and C70S30 fall within the "excellent" quality category. This study provides guidelines for optimizing mix designs and quality control protocols for sustainable concrete structures. Incorporating SBA and RHA as partial substitutes for OPC in concrete manufacturing can significantly reduce environmental impact by lowering CO₂ emissions and promoting the reuse of agro-waste, while also contributing to cost-effective and sustainable construction practices.