Utilization of Waste Generted by Thermal Powerplant (Coal Bottom Ash) in a Building Consturction Material

Abstract

Due to Utilizing natural resources and greenhouse gas emissions, the manufacturing of concrete has a substantial negative impact on the environment. Concrete manufacturing can have a positive environmental impact if Products made from industrial waste are part place of concrete or aggregates slag, silica fume, fly ash, and other industrial Waste materials are examples of waste materials that can be used in the making of concrete. The amount of garbage dumped in landfills and the carbon footprint connected with cement manufacture can both be decreased by using industrial waste during the making of concrete. However, qualities of the final concrete, such as setting, can also be impacted by the utilization of industrial waste in manufacturing. Before adding a specific waste material to concrete mixtures, careful thought must be given to how it will affect the concrete\'s qualities.

Introduction

Concrete is one of the most widely used construction materials, but its production has a significant environmental impact due to the consumption of natural resources and the emission of greenhouse gases. To reduce this impact, researchers have explored the use of industrial waste materials such as fly ash, silica fume, slag, and coal bottom ash (CBA) as partial replacements for cement or aggregates in concrete. This study investigates the use of ground coal bottom ash as a partial replacement material in M25-grade concrete and mortar to improve sustainability while maintaining strength and durability.

Objective

The main objective of the study is to evaluate the strength and performance of concrete containing ground coal bottom ash as a partial replacement material without relying heavily on superplasticizers. The study compares conventional concrete with concrete incorporating different percentages of bottom ash.

Literature Review

Previous research has highlighted the potential benefits of coal bottom ash in construction:

1. Coal Bottom Ash as Cement Replacement
   • CBA can improve concrete strength, durability, and microstructure when properly processed.
   • It provides an environmentally friendly disposal method for thermal power plant waste.
2. CBA in Self-Compacting Concrete (SCC)
   • Combining CBA with recycled concrete aggregates can produce sustainable SCC with comparable mechanical and durability properties.
   • The addition of metakaolin helps maintain performance even at high replacement levels.
3. CBA and Limestone Dust in Concrete
   • Partial replacement of sand with CBA and cement with limestone dust can improve strength and durability at lower replacement percentages (10–30%).
   • Higher replacement levels may reduce concrete performance.

Materials Used

Cement

• UltraTech OPC 53 Grade cement.

Fine Aggregate

• Natural river sand free from organic impurities.

Bottom Ash

• Collected from the Koradi Super Thermal Power Station.
• Rich in silica (48.71%) and alumina (29.23%), giving it pozzolanic properties useful in concrete production.

Superplasticizer

• Naphthalene-formaldehyde-based superplasticizer obtained from Vidarbha RMC Plant.
• Improves workability and strength while reducing water requirements.

Mix Proportions

The study used a mortar mix ratio of 1:4 (cement : fine aggregate).

Bottom ash replaced fine aggregate at:

• 0% (Control Mix)
• 10%
• 15%
• 20%
• 25%

Additional water and superplasticizer were added as the percentage of bottom ash increased to maintain workability.

Experimental Program

Sieve Analysis

• Conducted on both natural sand and bottom ash.
• Determined particle size distribution and grading.
• Helped compare the fineness of bottom ash with natural sand and assess its suitability for mortar production.

Material Testing

• Physical and chemical properties of bottom ash were evaluated before use.
• Strength and durability characteristics of the modified mixes were compared with conventional mortar.

Key Findings

• Ground coal bottom ash can serve as a sustainable replacement for natural materials in concrete and mortar.
• Proper grinding of coarse bottom ash particles improves performance.
• Moderate replacement levels (around 10–15%) generally provide the best balance between sustainability and mechanical performance.
• Using bottom ash reduces dependence on natural sand and cement, lowers waste disposal issues, and supports environmentally friendly construction practices.

Conclusion

1) Bottom ash is a waste material from coal-fired power plants. It is often thrown away in landfills, which harms the environment. This study explored how bottom ash can be used to replace natural sand in mortar mixes. The goal was to reduce waste and save natural resources. 2) Tests were done by replacing fine aggregate (sand) with bottom ash in different amounts: 0%, 10%, 15%, 20%, and 25%. The mortar cubes were tested for strength, workability, water absorption, and durability. The results showed that bottom ash can be safely used up to 15% without reducing the quality of the mortar. 3) When 10–15% of fine aggregate was replaced with bottom ash, the mortar still had good strength and performance. It was almost the same as the control mix with 0% bottom ash. This means bottom ash can work well in construction without affecting the final product too much. 4) The compressive strength of mortar decreased slightly when more than 15% bottom ash was used. However, at 10–15% replacement, the strength remained within acceptable limits. This shows that using a small to moderate amount of bottom ash is a safe and effective option. 5) The water absorption and sorptivity results also supported this finding. Mortars with up to 15% bottom ash had acceptable levels of water absorption. This means they are durable and can resist moisture well, which is important in construction. 6) Using bottom ash in mortar mixes helps in two ways. First, it reduces the need for natural sand. Natural sand is 7) becoming harder to find and its mining is causing damage to rivers and land. Second, it helps manage the waste produced by coal plants. Instead of dumping bottom ash, it can be reused in a useful way. 8) This method also saves cost. Bottom ash is cheaper than natural sand, so using it in mortar can reduce the overall cost of building materials. This makes it a good option for large-scale construction, especially in areas where natural sand is expensive or not easily available. 9) Future research can focus on improving the performance of mortar with higher levels of bottom ash. Also, combining bottom ash with other materials like fly ash or silica fume might give even better results. 10) In conclusion, bottom ash is a promising material for sustainable construction. It is cost-effective, eco-friendly, and performs well in mortar mixes. Using it helps reduce waste, protect natural resources, and promote greener building practices. It is a step towards cleaner and more responsible construction for the future.

References

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Copyright

Copyright © 2026 Mr. Ketan Bhongade, Mr Nikhil Wagare, Mr. Prajwal Nande, Mr. Gagan Gahane, Mr. Kunal Turankar, Divyani Harpal, Aasif Baig. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.