I am delighted to introduce Anoop P.P., a leading expert in the exciting world of biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More and its use in creating stronger, more sustainable building materials. Anoop is currently a researcher at the National Institute of Technology Karnataka, Surathkal, India, where he’s pursuing his highest degree, focusing on how special types of biochar, can help concrete and other building materials actually ‘heal’ themselves.

Anoop is particularly skilled in understanding how biochar can be mixed into materials to improve them. His work explores how to keep helpful bacteria alive and effective within these biochar mixtures, ensuring they can repair cracks and damage in structures over time. He’s essentially figuring out how to make buildings more resilient and environmentally friendly. His significant contributions include publishing research on how biochar, combined with certain bacteria, creates a ‘healing powder’ that keeps bacteria viable in self-healing mortar. He has also shown how biochar can be used to make powerful, long-lasting additives for bio-mortar production.

Anoop’s deep commitment to education is evident as he presently serves as a Lecturer in Civil Engineering at Government Polytechnic College, Kannur, Kerala, India. This dual role, combining rigorous academic research with hands-on practical experience, positions him as an invaluable voice in the biochar community. I am incredibly excited for him to share his unique insights with our readers.

 Shanthi Prabha: Anoop, it’s a genuine pleasure to have you with us today. Your research at the National Institute of Technology Karnataka, delving into “Biochar integrated microbial mortar for enhanced self-healing,” sounds incredibly innovative. First, could you share a bit about what initially drew you to this fascinating intersection of biochar and self-healing concrete, and what excites you about its potential?

Anoop P P: My research interest was driven by the need to develop durable and environmentally sustainable cementitious systems. Although microbial self-healing through Microbially Induced Calcium Carbonate Precipitation (MICP) has demonstrated significant potential, its practical implementation is often hindered by the limitations of conventional bacterial carriers. These materials are not carbon-negative and typically lack long-term storage capacity, reducing microbial viability over time. This led to the investigation of biochar as a microbial carrier, due to its ability to perform several critical functions. Its structured porous network, high surface area, and moisture-retentive properties facilitate the immobilization of bacterial spores and support their revival from dormant to vegetative state under favourable conditions. Importantly, the local pHpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More maintained by biochar plays a significant role in preserving microbial viability without disrupting cement hydration. Additionally, its chemical inertness ensures it does not react with or alter the hydration kinetics of the binder system. The carbon-sequestering nature of biochar also adds environmental value to its use in concrete. What I find most promising is the ability of biochar to enable biological healing mechanisms in concrete while contributing to carbon reduction and waste valorization, making it a technically and environmentally sound solution for next-generation self-healing materials.

SP: Your work mentions explicitly using coconut shell biochar in your research. What makes the coconut shell an excellent candidate for biochar production in the context of construction materials?

AP: Coconut shell is an excellent biomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More source for biochar production, particularly in construction applications, due to its high fixed carbon content, low ashAsh is the non-combustible inorganic residue that remains after organic matter, like wood or biomass, is completely burned. It consists mainly of minerals and is different from biochar, which is produced through incomplete combustion.   Ash Ash is the residue that remains after the complete More yield, and dense lignocellulosic structure. When subjected to thermal conversion processes such as pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More or gasificationGasification is a high-temperature, thermochemical process that converts carbon-based materials into a gaseous fuel called syngas and solid by-products. It takes place in an oxygen-deficient environment at temperatures typically above 750°C. Unlike combustion, which fully burns material to produce heat and carbon dioxide (CO2​), gasification More, coconut shell yields a hard, structurally stable biochar with high mechanical strength and durability, making it suitable for cementitious matrices. The resulting biochar exhibits a well-developed porous network and moderate surface functionalization, which contribute to its ability to retain moisture and physically immobilize bacterial spores. Moreover, coconut shell biochar has a relatively neutral pH and contains beneficial mineral elements such as potassium, calcium, and magnesium, which can support microbial viability without introducing toxicity or disrupting cement hydration.

Its non-pozzolanic nature also ensures that it does not interfere with the hydration process but provides a physically stable, inert micro-environment for biological activity. Additionally, the abundance of coconut shell waste in tropical regions adds a sustainability advantage, making it both environmentally and economically viable for scalable use in self-healing construction materials.

SP: You’ve explored the use of Bacterial strains in your biochar composites. What are the key advantages of these specific bacterial strains for self-healing applications, and how do you approach ensuring their long-term viability within the mortar?

AP: Selection of bacterial strains plays a crucial role in ensuring effective self-healing through MICP. In my study, spore-forming strains were selected based on high sporulation efficiency, urease activity, and tolerance to alkaline and desiccated conditions, which are typical of cementitious environments. The primary advantage of these strains lies in their ability to form endospores, allowing them to survive during mixing and storage without metabolic activity. Upon crack formation and moisture ingress, the spores undergo vegetative conversion and initiate calcium carbonate precipitation, leading to autonomous crack sealing.

To ensure long-term viability, the spores were immobilised in biochar. The structured pores and hydrophilic nature of biochar enabled retention of both moisture and spores, facilitating revival under favourable conditions. Viability analysis confirmed that the immobilised biochar preserved spore functionality for several months, addressing the challenge of frequent inoculation and incubation, and making it suitable for storage and on-demand usage in real-world construction applications.

SP: One of your recent publications discusses the effect of pyrolysis temperature on the characteristics, strength, hydration, and healing properties of your biochar-bio composite mortar. What were some of the most significant findings regarding the optimal pyrolysis temperature, and why is this parameter so crucial?

AP: Pyrolysis temperature significantly influences the physicochemical characteristics of biochar, which in turn affect microbial immobilization efficiency, hydration behavior, and self-healing performance of the mortar. In this study, coconut shell biomass was used as the feedstockFeedstock refers to the raw organic material used to produce biochar. This can include a wide range of materials, such as wood chips, agricultural residues, and animal manure. More, and biochar was produced at 300 °C, 400 °C, and 500 °C, maintaining a constant heating rate of 10 °C/min under a controlled inert atmosphere.

Biochar produced at 500 °C demonstrated higher fixed carbon content, reduced volatile matterVolatile matter refers to the organic compounds that are released as gases during the pyrolysis process. These compounds can include methane, hydrogen, and carbon monoxide, which can be captured and used as fuel or further processed into other valuable products.   More, greater thermal stability, and a more developed porous structure. These characteristics enhanced the retention and viability of immobilized bacterial spores and supported their vegetative conversion upon exposure to moisture during crack formation. Mortars incorporating this biochar exhibited improved compressive strength, crack healing efficiency, and ultrasonic pulse velocity, reflecting enhanced internal densification and healing capability. These findings are specific to coconut shell-derived biochar, and the optimal pyrolysis temperature may vary with different biomass types. In this case, 500 °C provided a favorable combination of pore structure, chemical stability, and microbial support, making it well-suited for biochar-based microbial self-healing systems.

SP: Your research contributes to “sustainable carbon sequestration and circular economy solutions.” Could you elaborate on how your biochar-integrated mortar contributes to these broader environmental goals?

AP: The integration of biochar into microbial self-healing mortar contributes meaningfully to carbon sequestration and circular economy objectives. Biochar, produced through the thermochemical conversion of agricultural waste such as coconut shells, possesses a highly stable carbon structure that resists microbial and chemical degradation. When incorporated into cementitious matrices, it acts as a durable carbon sink, retaining the fixed carbon in solid form over extended service life. In my research, coconut shell biochar generated at varying pyrolysis temperatures exhibited differences in carbon yield and stability. To assess its climate impact, net CO₂ avoidance was calculated by accounting for the carbon retained in the biochar and the emissions released during its production, providing a realistic measure of its sequestration potential.

From a circular economy perspective, this approach adds value to locally available biomass by transforming it into a functional microbial carrier that enhances crack healing efficiency. This not only reduces the use of synthetic additives but also extends the durability of concrete structures, minimizing material consumption and repair interventions. Overall, biochar-integrated mortar offers a low-emission, high-performance pathway toward sustainable infrastructure development.

SP: Beyond the self-healing aspect, what other benefits, such as improved durability or reduced environmental footprint, do you foresee from the widespread adoption of biochar-integrated concrete in construction?

AP: Beyond self-healing, the incorporation of biochar into cementitious systems provides several additional benefits that can significantly enhance both the durability and environmental performance of concrete. The porous structure of biochar facilitates internal curing by retaining moisture within the matrix, which supports continued hydration and reduces the risk of autogenous shrinkage. This contributes to a denser microstructure with lower permeability, improving resistance to ingress of aggressive agents such as chlorides and sulphates, and thereby extending the service life of concrete structures. From a sustainability perspective, biochar enables partial replacement of cement or inert fillers, leading to reduced embodied energy and carbon emissions. Since it is derived from agricultural residues, its utilization supports waste valorization and contributes to circular economy objectives.

Furthermore, the stable carbon content of biochar allows it to function as a long-term carbon sink when embedded in concrete, effectively offsetting a portion of the emissions associated with cement production. When combined with microbial immobilization, the system not only promotes autonomous healing but also reduces the frequency of maintenance interventions, lowering the material and energy demands over the lifecycle of the structure. These combined effects position biochar-integrated mortar as a multifunctional, climate-responsive material for advancing sustainable and durable infrastructure.

SP: You’ve also investigated the performance of bio-mortar enhanced with coconut shell biochar bi-ocomposite under varying salinity conditions in a marine environment. What challenges did you encounter in this specific application, and how did your research begin to address them?

AP: Investigating the performance of bio-mortar incorporating coconut shell biochar bi-ocomposite under varying salinity conditions posed several challenges, particularly related to bacterial viability and healing efficiency in high-ionic environments. One of the primary concerns was that elevated salinity levels can exert osmotic stress on bacterial spores, potentially inhibiting germination and reducing the efficiency of MICP. Additionally, saline environments can alter the ionic composition of the pore solution, which may interfere with both microbial activity and the stability of the precipitated calcite.

To address these challenges, the study evaluated spore viability, healing performance, and compressive strength recovery under varying salinity levels. It was observed that while higher salinity levels led to a gradual decline in healing efficiency, certain bacterial strains maintained activity up to specific threshold concentrations. The immobilisation of spores in coconut shell biochar proved to be beneficial, as the structured pores and moisture retention capacity of the biochar provided a protective microenvironment, helping to buffer the impact of salinity and sustain bacterial functionality.

Moreover, performance parameters such as crack width closure, ultrasonic pulse velocity, and electrical resistivity were monitored to understand the extent of healing and internal densification. The results demonstrated that biochar-based systems can maintain healing functionality under moderate salinity conditions, indicating their potential for use in marine-exposed structures. However, the research also highlighted the importance of selecting salt-tolerant bacterial strains and optimizing immobilisation conditions to enhance system resilience under harsh exposure environments.

SP: Given your experience, what are some of the critical considerations or challenges in scaling up the production and application of biochar-based self-healing materials for larger construction projects?

AP: Scaling up the production of biochar-based healing powder requires the use of a large pyrolysis reactor with precise technical and thermal specifications to ensure uniform heat distribution throughout the reactor. This uniformity is critical for producing biochar with consistent physical properties, which enhances the immobilization efficiency. Additionally, evaluating the leachingLeaching is the process where nutrients are dissolved and carried away from the soil by water. This can lead to nutrient depletion and environmental pollution. Biochar can help reduce leaching by improving nutrient retention in the soil.   More of volatile and non-volatile organics and heavy metals is crucial to addressing potential environmental impacts and ensuring the long-term performance of mortar. Another major challenge lies in the variability of biomass feedstocks. Different raw materials exhibit distinct behaviours during pyrolysis, leading to variations in porosityPorosity of biochar is a key factor in its effectiveness as a soil amendment and its ability to retain water and nutrients. Biochar’s porosity is influenced by feedstock type and pyrolysis temperature, and it plays a crucial role in microbial activity and overall soil health. Biochar More, micronutrient composition, and surface functional groups. With a wide range of agricultural residues available for biochar production, fixing these parameters and maintaining consistency is essential to ensure reliable performance. These considerations are vital for the scalability and sustainable application of biochar-based healing technologies.

SP: What are the next frontiers in biochar research for construction materials that you find particularly exciting or believe hold significant promise for the industry?

AP: Future research in biochar for construction should focus on three main directions. First is the optimisation of biochar as a cement replacement, including tailoring surface reactivity, particle fineness, and compatibility with hydration products to enable higher replacement levels without compromising strength. Second is the development of biochar-based lightweight aggregates that serve both structural and healing functions. These aggregates can be engineered for targeted bacterial delivery, controlled moisture retention, and crack-responsive release.

The third direction is the standardisation of production protocols, considering that different biomass feedstocks produce biochars with varying properties. Establishing feedstock-specific pyrolysis parameters and material quality benchmarks is essential for large-scale application. Advancing these areas will help transition biochar-based materials from experimental systems to practical solutions in sustainable infrastructure.

SP: You have a diverse professional background, including experience as a Lecturer, Vocational Teacher, and Draftsman, alongside your academic pursuits. How has this varied experience influenced your approach to research and problem-solving in civil engineering?

AP: My diverse professional background has significantly shaped my approach to research and problem-solving in civil engineering. Working as a Draftsman early in my career gave me a strong foundation in practical detailing, material behavior, and construction-level precision, which helped me appreciate the importance of translating design into executable solutions. Later, as a Vocational Teacher and then a Lecturer, I gained experience in simplifying complex engineering concepts, mentoring students, and staying updated with evolving technologies and standards.

This combination of field-level understanding and academic engagement allows me to approach research problems with both technical depth and practical relevance. It has also instilled a mindset of solution-oriented thinking, where I prioritise feasibility, applicability, and long-term performance when designing and testing new materials such as biochar-integrated systems. Moreover, my teaching experience has sharpened my ability to critically evaluate results, communicate findings effectively, and align experimental work with real-world needs in infrastructure.

SP: What advice would you offer for aspiring researchers or students interested in sustainable construction materials, particularly biochar, based on your journey and expertise?

AP: For aspiring researchers and students interested in sustainable construction materials, particularly biochar, my key advice would be to build a strong foundation in material science and cement chemistry, as understanding the interaction between novel additives and cementitious systems is essential. Biochar is a complex material whose properties vary significantly with feedstock type, pyrolysis temperature, and heating rate, so research must be rooted in detailed characterisation and controlled experimentation.

It is equally important to gain practical exposure to standardised testing methods, durability assessments, and microstructural analysis techniques, as these are critical for evaluating the performance of biochar-integrated systems. Additionally, always consider the scalability, environmental impact, and long-term behaviour of materials, since these factors determine their feasibility for real-world implementation.

Most importantly, stay curious, remain persistent, and be open to refining your methodology based on experimental outcomes and material behaviour. Biochar research is inherently interdisciplinary, bridging civil engineering, environmental sustainability, and material processing. With a clear understanding of application needs and continuous improvement in research design, your work can contribute meaningfully to advancing sustainable infrastructure solutions.

SP: If you could choose one key takeaway or message about the potential of biochar in civil engineering that you’d like the audience to remember, what would it be?

AP: If there is one key message I would like the audience to remember, it is that biochar offers a versatile and scalable pathway toward low-carbon, high-performance construction materials. Whether used as a microbial carrier for self-healing, a supplementary cementitious component, a lightweight aggregate, or even a support for thermal regulation, biochar enables the integration of durability, sustainability, and resource efficiency in civil engineering. Its ability to transform biomass residues into functional infrastructure materials makes it a promising solution for addressing both performance demands and environmental challenges in the built environment.

SP: Your work has been published in several reputable journals and includes patent filings. For our readers interested in following your ongoing research and publications, what are the best platforms or resources where they can track your work?

AP:The best way to stay updated on my research and latest developments is to follow me directly through these links:

• Google Scholar: https://scholar.google.com/citations?hl=en&user=55uOja4AAAAJ
• ResearchGate: https://www.researchgate.net/profile/Anoop-P-P
• LinkedIn: https://in.linkedin.com/in/anoop-p-p-606668202

I regularly share updates on my publications, ongoing work with biochar-based materials, and new advancements like patents and conference presentations. These platforms serve as a bridge, connecting academic research with practical applications, particularly in sustainable materials and construction innovation