Concrete, Durability, Service life, Probabilistic estimation
19
Scopus Publications
834
Scholar Citations
10
Scholar h-index
10
Scholar i10-index
Scopus Publications
Acid Resistance of Cement Mixes Containing Waste Catalysts Derived from Oil Refineries Natalia Szemiot-Jankowska, Shriram Marathe, Murugan Muthu, Kamil Krzywiński, Andrzej Michałek, Sundar Rathnarajan, Łukasz Sadowski Journal of Structural Design and Construction Practice, 2026 This study examines the feasibility of an equilibrium catalyst (ECAT) from petrochemical waste as an interim substitute for cement in mortar, with the objective of reducing cement consumption, production costs, and CO2 emissions. Mortar samples were prepared with ECAT substitution levels of 0%, 10%, 20%, and 30% and assessed for workability, mechanical strength, microstructure, and durability under acidic conditions. Results demonstrated that increasing ECAT content reduced flowability by up to 49%, primarily due to the high porosity of ECAT, which absorbed water. Calorimetry and compressive strength tests revealed that ECAT additions led to a 17% reduction in cumulative heat release and a 53% decrease in strength at 30% replacement, likely due to reduced cement hydration. Acid resistance was enhanced in ECAT-based mortars, with significantly lower strength and weight losses under HNO3 exposure compared to the reference mix, attributed to reduced ion leaching. Microstructural analysis via scanning electron microscopy and x-ray diffraction identified increased amorphous content and the presence of faujasite, which contributed to enhanced durability. Although high ECAT content lowered mechanical performance, mortars with up to 30% ECAT demonstrated satisfactory resistance to acid degradation, suggesting that ECAT is a viable supplementary cementitious material. Given the environmental impact of petrochemical waste, this approach supports sustainable waste repurposing while maintaining mortar quality, aligning with anticipated regulatory shifts in waste recycling for petrochemical by-products.
Seawater-mixed concretes containing supplementary cementitious materials: compressive strength, e-modulus, electrical resistivity, and life cycle assessment Sundar Rathnarajan, Joao Nuno Pacheco, Francisco Capucha, Javier Valencia, Mateusz Techman, Pawel Sikora Archives of Civil and Mechanical Engineering, 2025 Water and concrete are the materials humans consume the most on earth. By 2040, several countries are expected to face extreme water stress and the need for significant growth in their infrastructure simultaneously. Water is a fundamental ingredient for concrete production, and the need for infrastructure growth can further increase the water demand for concrete production and thus affect these regions facing water scarcity. Including supplementary cementitious materials (SCMs), non-metallic fibres, and coated/polymer reinforcements can increase the feasibility of producing concrete with seawater (SW). There is a lack of information on the long-term strength and durability properties of SW-mixed concretes (SWC) produced with SCMs. This paper optimises binder compositions with CEM I, fly ash, ground granulated blast furnace slag (slag), and metakaolin suitable for adapting SWC based on performance indicators. Binary and ternary blended concretes of similar binder content (360 kg/m3) and w/b (0.45) were designed and cast with the SCMs mentioned above. Compressive strength, surface resistivity, and accelerated carbonation tests were conducted on the concrete produced with freshwater (FW) and seawater (SW). SWC produced with 30% slag and 15% metakaolin had higher electrical resistivity and an improvement in compressive strength (up to 30%) than other combinations used for producing SWC. Life cycle assessment identified that the concretes produced with fly ash, and ternary combination of fly ash and metakaolin had the least water depletion potential (WDP) compared to other SW-mixed concretes. Also, the replacement of FW by SW reduces the WDP up to 50%.
10-year natural carbonation data of concretes with limestone, fly ash, volcanic ash, and slag and exposed to tropical climate in India Umesh Hule, Sundar Rathnarajan, Radhakrishna G. Pillai, Ravindra Gettu, Manu Santhanam Data in Brief, 2024 The adoption of supplementary cementitious materials (SCMs) as a partial replacement of Ordinary Portland Cement (OPC) is increasing in anticipation of reducing the carbon footprint of cement and concrete industry. The resistance of concretes with SCMs against natural carbonation (a reactive-diffusion mechanism) is still a topic of research. Most literature adopt accelerated carbonation tests (under constant humidity and temperature conditions) to estimate the natural carbonation depth (d CO2 ) in concrete. This does not always represent the actual scenario in the field structures. Moreover, accelerated carbonation conditions could result in significantly different pore structure than that are formed in the case of natural carbonation; hence, not always reliable to model the service life. Hence, there is a need for data on long-term natural d CO2 to help design reinforced concrete for a target service life. The data presented in this paper contains long-term natural d CO2 data of 45 different concretes prepared using various SCMs like volcanic ash (from Greece), fly ash, slag, and limestone (from France). The concrete specimens were prepared in France, shipped to India by air (in moist burlap and plastic cover), and then kept in sheltered and unsheltered exposure conditions on the terrace of a building in Chennai, India, experiencing tropical climate (warm and humid conditions). The data includes mixture proportions (type of binder, water-to-binder ratio, binder content, % SCMs, fine and coarse aggregate (river sand and gravel) content, and air content). In addition, curing time and compressive strength of concrete mixes are provided in Set A. Sets B and C consist of the natural d CO2 of concrete measured at various time instances between 1 and 11 years of natural exposure. Arguably, this is the first of its kind natural d CO2 database from a tropical climate zone. The natural d CO2 values were measured using a phenolphthalein indicator prepared according to RILEM CPC 18. This data can be used by researchers and practitioners to calibrate the existing carbonation models or to develop new models to estimate natural d CO2 for concretes exposed to tropical climates. Such models can help design concretes to achieve the target corrosion-free service life for reinforced concrete systems.
Report of RILEM TC 281-CCC: insights into factors affecting the carbonation rate of concrete with SCMs revealed from data mining and machine learning approaches A. Vollpracht, G. J. G. Gluth, B. Rogiers, I. D. Uwanuakwa, Q. T. Phung, Y. Villagran Zaccardi, C. Thiel, H. Vanoutrive, J. M. Etcheverry, E. Gruyaert, S. Kamali-Bernard, A. Kanellopoulos, Z. Zhao, I. M. Martins, S. Rathnarajan, N. De Belie Materials and Structures Materiaux Et Constructions, 2024 The RILEM TC 281–CCC ‘‘Carbonation of concrete with supplementary cementitious materials’’ conducted a study on the effects of supplementary cementitious materials (SCMs) on the carbonation rate of blended cement concretes and mortars. In this context, a comprehensive database has been established, consisting of 1044 concrete and mortar mixes with their associated carbonation depth data over time. The dataset comprises mix designs with a large variety of binders with up to 94% SCMs, collected from the literature as well as unpublished testing reports. The data includes chemical composition and physical properties of the raw materials, mix-designs, compressive strengths, curing and carbonation testing conditions. Natural carbonation was recorded for several years in many cases with both indoor and outdoor results. The database has been analysed to investigate the effects of binder composition and mix design, curing and preconditioning, and relative humidity on the carbonation rate. Furthermore, the accuracy of accelerated carbonation testing as well as possible correlations between compressive strength and carbonation resistance were evaluated. One approach to summerise the physical and chemical resistance in one parameter is the ratio of water content to content of carbonatable CaO (w/CaOreactive ratio). The analysis revealed that the w/CaOreactive ratio is a decisive factor for carbonation resistance, while curing and exposure conditions also influence carbonation. Under natural exposure conditions, the carbonation data exhibit significant variations. Nevertheless, probabilistic inference suggests that both accelerated and natural carbonation processes follow a square-root-of-time behavior, though accelerated and natural carbonation cannot be converted into each other without corrections. Additionally, a machine learning technique was employed to assess the influence of parameters governing the carbonation progress in concretes.
Comprehensive evaluation of early-age hydration and compressive strength development in seawater-mixed binary and ternary cementitious systems Sundar Rathnarajan, Krzysztof Cendrowski, Daniel Sibera, Pawel Sikora Archives of Civil and Mechanical Engineering, 2024 Seawater-mixed concrete (SWC) is a proposed solution for catering to the needs of developing nations facing extremely severe water stress. Recent research works advocate the feasibility of producing SWC by adding supplementary cementitious materials (SCMs) and alternative reinforcements without reducing the engineering properties of the same. However, limited information is available for optimising the type and amount of SCMs in binary and ternary blended SW-mixed cementitious systems for achieving desirable strength development and early-age hydration. A comprehensive study to understand the evolution of heat of hydration and strength up to 28 days was conducted on 31 binder compositions mixed with both fresh water (FW) and seawater (SW). Fly ash, slag, metakaolin, and limestone are the supplementary cementitious materials used with CEM I as a primary binder at a replacement level between 10 and 70%. Isothermal calorimetry results revealed an increase in total heat of hydration and a reduction in setting time with SW-mixed cement pastes compared to their FW-mixed counterparts. Similarly, a significant increase in strength between 0 and 50% was observed in SW-mixed cement pastes. Suitable binder combinations showing an increase in compressive strength and not a significant reduction in strength compared to the CEM I reference mix were identified using the strength improvement factor approach. Binary and ternary blended cementitious, consisting of fly ash, slag, and metakaolin at different replacement levels, are amongst the chosen binder combinations.
Seawater-mixed concretes containing natural and sea sand aggregates – A review Sundar Rathnarajan, Pawel Sikora Results in Engineering, 2023 In light of global warming and the rising urban population across the world, freshwater is becoming a scarce commodity. Freshwater consumption in the production of concrete makes up a significant (9%) share of total freshwater withdrawal for industrial purposes. Among the alternative sources of water for concrete production, seawater involves minimal processing, besides screening debris with filters. Other options, such as the use of wastewater from industrial effluent or desalination of hard waters, require a significant amount of energy, which add to overall concrete production emissions. Many efforts have been made by researchers in the last decades to understand the behaviour of seawater-mixed and sea sand concretes (SW-SS). The present work evaluates the early-age hydration, fresh, mechanical, and durability performance of SW-SS concretes and the corrosion characteristics of embedded reinforcement in them. The authors also summarize mitigation measures recommended in the literature for improving the anti-corrosion performance of SW-SS concretes, by partial substitution of supplementary cementitious materials (SCMs), the inclusion of alternative reinforcements (such as stainless steel and fibre reinforced polymer bars), the incorporation of corrosion inhibitors, and the adaptation of cathodic prevention measures. Finally, the article highlights the possible challenges to, opportunities for and potential applications of SW-SS concretes in the near future, so as to combat the freshwater crisis in nations suffering severe water stress.
Seawater-Mixed Lightweight Aggregate Concretes with Dune Sand, Waste Glass and Nanosilica: Experimental and Life Cycle Analysis Pawel Sikora, Levent Afsar, Sundar Rathnarajan, Morteza Nikravan, Sang-Yeop Chung, Dietmar Stephan, Mohamed Abd Elrahman International Journal of Concrete Structures and Materials, 2023 The use of alternative and locally available materials is encouraged in the construction industry to improve its sustainability. Desert regions with shortages in freshwater and river sand as fine aggregates in concrete have to search for alternative materials such as seawater, dune sand, and waste glass powder to produce lightweight concretes. The potential negative effects of adding these alternative materials can be reduced by adding nanosilica to the cementitious system at very low quantities. This study evaluates the feasibility of using these alternative materials and nanosilica (NS) in producing lightweight aggregate concretes (LWACs). A systematic study was carried out to understand the synergistic effect of nanosilica and seawater in improving the hydration characteristics of the developed cementitious systems. Also, the effect of these alternative materials on the fresh properties of the cementitious system was assessed by slump flow tests. The evolution of compressive strength at early ages was investigated after 2, 7, and 28 days of moist curing and an improvement in the strength development in concretes with seawater was observed. Furthermore, the integrity of the developed LWACs was analyzed using oven-dry density, thermal conductivity, water porosity and shrinkage measurements. Moreover, the capillary porosity and sorptivity measurements revealed the denser microstructure in the nano-modified seawater lightweight concretes. In the end, the life-cycle assessment study calculated the benefit of alternative materials in terms of carbon footprint and water consumption. As an outcome, a sustainable solution for producing LWACs containing seawater, dune sand or glass powder was proposed.
Impact of different climates on the resistance of concrete to natural carbonation Quoc Huy Vu, Gabriel Pham, Alain Chonier, Eric Brouard, Sundar Rathnarajan, Radhakrishna Pillai, Ravindra Gettu, Manu Santhanam, Federico Aguayo, Kevin J. Folliard, Michael D. Thomas, Ted Moffat, Caijun Shi, Anup Sarnot Construction and Building Materials, 2019
Carbonation and its effect on microstructure of concrete with fly ASH and ground granulated blast furnace slag Indian Concrete Journal, 2019
Service life and life-cycle assessment of reinforced concrete with fly ash and limestone calcined clay cement 6th International Conference on Durability of Concrete Structures Icdcs 2018, 2018
RECENT SCHOLAR PUBLICATIONS
Acid Resistance of Cement Mixes Containing Waste Catalysts Derived from Oil Refineries N Szemiot-Jankowska, S Marathe, M Muthu, K Krzywiński, A Michałek, ... Journal of Structural Design and Construction Practice 31 (1), 04025104 , 2026 2026
Carbonation models using mix-design parameters for concretes with supplementary cementitious materials S Rathnarajan, RG Pillai Journal of Building Engineering 104, 112392 , 2025 2025 Citations: 11
Use of seawater as an accelerator in 3D printed concrete (3DPC) P Sikora, S Rathnarajan, K Federowicz, M Techman, H Al-kroom Materials Letters 381, 137781 , 2025 2025 Citations: 4
Seawater-mixed concretes containing supplementary cementitious materials: compressive strength, e-modulus, electrical resistivity, and life cycle assessment S Rathnarajan, JN Pacheco, F Capucha, J Valencia, M Techman, ... Archives of Civil and Mechanical Engineering 25 (2), 69 , 2025 2025 Citations: 6
10-year natural carbonation data of concretes with limestone, fly ash, volcanic ash, and slag and exposed to tropical climate in India U Hule, S Rathnarajan, RG Pillai, R Gettu, M Santhanam Data in Brief 57, 111006 , 2024 2024 Citations: 5
Report of RILEM TC 281-CCC: insights into factors affecting the carbonation rate of concrete with SCMs revealed from data mining and machine learning approaches A Vollpracht, GJG Gluth, B Rogiers, ID Uwanuakwa, QT Phung, ... Materials and structures 57 (9), 206 , 2024 2024 Citations: 29
Comprehensive evaluation of early-age hydration and compressive strength development in seawater-mixed binary and ternary cementitious systems S Rathnarajan, K Cendrowski, D Sibera, P Sikora Archives of Civil and Mechanical Engineering 24 (2), 121 , 2024 2024 Citations: 14
Carbonation of Concretes with SCMs A Vollpracht, GJG Gluth, B Rogiers, ID Uwanuakwa, QT Phung, ... CONSEC24, 161-164 , 2024 2024
Sustainable Nano-modified Seawater Concrete with Enhanced Service Life (NanoSeaCon) S Rathnarajan, P Sikora, W Stawowy CONSEC 2024 , 2024 2024
CORROSION ASSESSMENT OF EMBEDDED REINFORCEMENT IN NANO-MODIFIED SEAWATER-MIXED CONCRETE S Rathnarajan, P Sikora RILEM Week 2024 , 2024 2024
Seawater-mixed concretes containing natural and sea sand aggregates–a review S Rathnarajan, P Sikora Results in Engineering 20, 101457 , 2023 2023 Citations: 43
Seawater-mixed lightweight aggregate concretes with dune sand, waste glass and nanosilica: experimental and life cycle analysis P Sikora, L Afsar, S Rathnarajan, M Nikravan, SY Chung, D Stephan, ... International journal of concrete structures and materials 17 (1), 47 , 2023 2023 Citations: 18
Long-Term Natural Carbonation in Concretes with Fly Ash and Limestone Calcined Clay Systems S Rathnarajan, U Hule, RG Pillai, R Gettu International RILEM Conference on Synergising expertise towards … , 2023 2023
A STUDY ON PERFORMANCE OF CLAY BASED GEOPOLYMERS AT ELEVATED TEMPERATURES S Manohar, KM HANEEFA, S RATHNARAJAN, M SANTHANAM INDIAN CONCRETE JOURNAL , 2022 2022
Carbonation model for concretes with fly ash, slag, and limestone calcined clay-using accelerated and five-year natural exposure data S Rathnarajan, BS Dhanya, RG Pillai, R Gettu, M Santhanam Cement and Concrete Composites 126, 104329 , 2022 2022 Citations: 95
Modelling Carbonation in Concretes with Fly ash, Slag, or Limestone Calcined Clay and Corrosion Assessment of Embedded Steel S Rathnarajan Indian Institute of Technology Madras , 2022 2022
Restoration of Reinforced Lime Concrete Sunshades of a Century Old Heritage Building in New Delhi, India D Joseline, H Haridasan, S Rathnarajan, D Rani, T Raja, RG Pillai, ... Structural Analysis of Historical Constructions: An Interdisciplinary … , 2019 2019 Citations: 3
Impact of different climates on the resistance of concrete to natural carbonation QH Vu, G Pham, A Chonier, E Brouard, S Rathnarajan, R Pillai, R Gettu, ... Construction and Building Materials 216, 450-467 , 2019 2019 Citations: 64
Carbonation and its effect on microstructure of concrete with fly ash and ground granulated blast furnace slag BS Dhanya, S Rathnarajan, M Santhanam, RG Pillai, R Gettu Indian Concrete Journal 93 (4), 10-21 , 2019 2019 Citations: 8
Service life and life cycle assessment of reinforced concrete systems with limestone calcined clay cement (LC3) RG Pillai, R Gettu, M Santhanam, S Rengaraju, Y Dhandapani, ... Cement and Concrete Research 118, 111-119 , 2019 2019 Citations: 395
MOST CITED SCHOLAR PUBLICATIONS
Service life and life cycle assessment of reinforced concrete systems with limestone calcined clay cement (LC3) RG Pillai, R Gettu, M Santhanam, S Rengaraju, Y Dhandapani, ... Cement and Concrete Research 118, 111-119 , 2019 2019 Citations: 395
Sustainability-based decision support framework for choosing concrete mixture proportions R Gettu, R Pillai G., M Santhanam, A Basavaraja S, S Rathnarajan, ... Materials and Structures 51 (165), 1-16 , 2018 2018 Citations: 105
Carbonation model for concretes with fly ash, slag, and limestone calcined clay-using accelerated and five-year natural exposure data S Rathnarajan, BS Dhanya, RG Pillai, R Gettu, M Santhanam Cement and Concrete Composites 126, 104329 , 2022 2022 Citations: 95
Impact of different climates on the resistance of concrete to natural carbonation QH Vu, G Pham, A Chonier, E Brouard, S Rathnarajan, R Pillai, R Gettu, ... Construction and Building Materials 216, 450-467 , 2019 2019 Citations: 64
Seawater-mixed concretes containing natural and sea sand aggregates–a review S Rathnarajan, P Sikora Results in Engineering 20, 101457 , 2023 2023 Citations: 43
Report of RILEM TC 281-CCC: insights into factors affecting the carbonation rate of concrete with SCMs revealed from data mining and machine learning approaches A Vollpracht, GJG Gluth, B Rogiers, ID Uwanuakwa, QT Phung, ... Materials and structures 57 (9), 206 , 2024 2024 Citations: 29
Seawater-mixed lightweight aggregate concretes with dune sand, waste glass and nanosilica: experimental and life cycle analysis P Sikora, L Afsar, S Rathnarajan, M Nikravan, SY Chung, D Stephan, ... International journal of concrete structures and materials 17 (1), 47 , 2023 2023 Citations: 18
Comprehensive evaluation of early-age hydration and compressive strength development in seawater-mixed binary and ternary cementitious systems S Rathnarajan, K Cendrowski, D Sibera, P Sikora Archives of Civil and Mechanical Engineering 24 (2), 121 , 2024 2024 Citations: 14
Service life and life-cycle assessment of reinforced concrete with fly ash and limestone calcined clay cement R Gettu, RG Pillai, M Santhanam, S Rathnarajan, A Basavaraj, S Raju, ... 2019 Citations: 12
Carbonation models using mix-design parameters for concretes with supplementary cementitious materials S Rathnarajan, RG Pillai Journal of Building Engineering 104, 112392 , 2025 2025 Citations: 11
Carbonation rate and service life of reinforced concrete systems with mineral admixtures and special cements S Rathinarajan, R Pillai Proceedings of the CORCON, Mumbai, India, 17-20 , 2017 2017 Citations: 9
Carbonation and its effect on microstructure of concrete with fly ash and ground granulated blast furnace slag BS Dhanya, S Rathnarajan, M Santhanam, RG Pillai, R Gettu Indian Concrete Journal 93 (4), 10-21 , 2019 2019 Citations: 8
Modelling carbonation rates in concretes with similar strength and with and without slag S Rathnarajan, NP Vaddey, RG Pillai, R Gettu, M Santhanam Conference: ICACMS , 2017 2017 Citations: 7
Seawater-mixed concretes containing supplementary cementitious materials: compressive strength, e-modulus, electrical resistivity, and life cycle assessment S Rathnarajan, JN Pacheco, F Capucha, J Valencia, M Techman, ... Archives of Civil and Mechanical Engineering 25 (2), 69 , 2025 2025 Citations: 6
10-year natural carbonation data of concretes with limestone, fly ash, volcanic ash, and slag and exposed to tropical climate in India U Hule, S Rathnarajan, RG Pillai, R Gettu, M Santhanam Data in Brief 57, 111006 , 2024 2024 Citations: 5
Use of seawater as an accelerator in 3D printed concrete (3DPC) P Sikora, S Rathnarajan, K Federowicz, M Techman, H Al-kroom Materials Letters 381, 137781 , 2025 2025 Citations: 4
Effect of corrosion inhibitors on durability parameters of cement mortar S Rengaraju, S Rathnarajan, R Pillai, AV Ajithakumari, O Pugal, RG Pillai CORCON 2015 , 2015 2015 Citations: 4
Restoration of Reinforced Lime Concrete Sunshades of a Century Old Heritage Building in New Delhi, India D Joseline, H Haridasan, S Rathnarajan, D Rani, T Raja, RG Pillai, ... Structural Analysis of Historical Constructions: An Interdisciplinary … , 2019 2019 Citations: 3
Determination of pH threshold of corrosion initiation in cementitous systems with supplementary cementitious materials S Rathnarajan, RG Pillai CORSYM, Chennai, India, 1-3 , 2018 2018 Citations: 2
Acid Resistance of Cement Mixes Containing Waste Catalysts Derived from Oil Refineries N Szemiot-Jankowska, S Marathe, M Muthu, K Krzywiński, A Michałek, ... Journal of Structural Design and Construction Practice 31 (1), 04025104 , 2026 2026
