Journals
Conferences
Posters
Journals
I. Papakonstantinou et al. Nanoparticulate selective emitters for effective radiative cooling in urban heat islands, Nature Portfolio, 2026. (preprint)
A. Rubio-Aguinaga, L. Kyriakou, J.M. Fernández, Í. Navarro-Blasco and J.I. Álvarez, Form-stable PCMs in lime renders: From particle-matrix interactions to thermal buffering and durability, Construction and Building Materials 537:147166, 2026 [invited].
The development of thermally responsive lime renders has been constrained by the lack of materials capable of storing and releasing heat without compromising compatibility, durability or the microstructural integrity required in both modern and heritage applications. Although form-stable phase change materials (PCMs) offer a promising route for latent-heat storage, their behaviour within lime matrices remains insufficiently explored. This study addresses this gap through a comprehensive, multi-scale investigation of lime renders incorporating silica-supported PCMs, linking particle-level interactions to thermal performance and long-term durability. These findings demonstrate that silica-supported PCMs can be effectively integrated into lime renders to deliver meaningful thermal regulation while maintaining compatibility, structural integrity, and long-term performance, highlighting their potential for energy-responsive and heritage-compatible construction materials.
M.H. Nofalah, L. Kyriakou, J.M. Fernández, Í. Navarro-Blasco and J.I. Álvarez, The Influence of Metakaolin-to-Vaterite Ratio on the Properties of Vaterite-Calcined Clay Cement: Fresh mortar rheology, Microstructure, and Mechanical Performance, Journal of Building Engineering, 128:116654, 2026.
This study investigates the influence of the metakaolin-to-vaterite (MK/V) ratio on the fresh properties, mechanical performance, and microstructural development of vaterite-calcined clay cement (VC3) mortars. Eight mixtures were produced with MK/V ratios between 1.0 and 3.0, alongside a limestone-calcined clay cement (LC3) reference. [...] Overall, the MK/V ratio was found to regulate the interplay between rheology, hydration, and microstructure, identifying 2.0-2.5 as the optimal range for balanced performance. Given that vaterite can be produced via carbon-negative synthesis routes that permanently store captured CO2, ternary samples including metakaolin emerge as a technically robust and environmentally beneficial alternative for next-generation low-clinker cements.
A. Rubio-Aguinaga, L. Kyriakou, J.M. Fernández, Í. Navarro-Blasco and J.I. Álvarez, Multi-PCM lime mortars incorporating polymer-shell and form-stable Phase Change Materials for energy-efficient building envelopes, Polymers, 18:1481, 2026.
This study investigates the design and performance of lime mortars incorporating multi-phase change material (multi-PCM) systems as thermally responsive rendering materials for building-envelope applications under variable conditions. Moving beyond conventional single-PCM lime mortar approaches, this work proposes a controlled multi-PCM design framework in which a fixed total PCM dosage is distributed across selected phase-transition windows. Mortars combining PCMs with different transition temperatures (5–25 °C and 18–25 °C) were produced using two PCM types: silica-supported form-stable systems and polymeric-shell microencapsulated systems supplied as powders or aqueous slurries. [...] Environmental and economic analyses highlighted that the benefits of PCM incorporation depend on matching PCM transition temperatures to specific climatic and application requirements. These findings position multi-PCM lime mortars as a promising route towards climate-adapted, thermally responsive renders with distributed and tailorable activation profiles.
A. Rubio-Aguinaga, L. Kyriakou, J.M. Fernández, Í. Navarro-Blasco and J.I. Álvarez, Evaluating the durability and cyclic thermal performance of lime mortars with microencapsulated PCMs for sustainable energy solutions, Construction and Building Materials, 530:146628, 2026.
Phase change materials (PCMs) have emerged as promising additives for lime renders aimed at moderating indoor temperatures and reducing heating and cooling demand in retrofit applications, including Built Heritage. However, existing studies largely report durability as a macroscopic pass-fail outcome and emphasize initial thermal benefits, with limited evidence on whether thermal functionality is retained after severe environmental ageing. This study addresses this gap by combining durability assessment with an integrated evaluation of post-exposure changes in microstructure, mechanical performance, and, critically, the conservation of thermal behaviour and thermal cyclability. [...] The results showed, first, that metakaolin-containing mortars exhibited significantly enhanced durability, successfully withstanding freeze-thaw and salt attack, whereas formulations without metakaolin failed prematurely. Following durability exposure, these optimized formulations displayed a refined pore network and preserved or improved mechanical performance, with compressive strength increases of up to 460%. Regarding the preservation of thermal functionality, PCM-metakaolin formulations generally exceeded 90% thermal agreement and reached 100% in several cases, while maintaining stable heat storage and release under repeated cycling. Overall, the results demonstrate that, when appropriately formulated, PCM-lime renders can combine durability with persistent and cyclable thermal performance, supporting their feasibility as long-lasting solutions for energy-efficient rehabilitation.
L. Kyriakou, A. Rubio-Aguinaga, M.H. Nofalah, L.M. Piarulli Paz, Á. Garcia Molino, L. Ferrara, I. Karatasios, E. Tziviloglou, J.M. Fernández, Í. Navarro-Blasco and J.I. Álvarez, From Laboratory Formulation to In Situ Evaluation: PCM-Enhanced Lime-Pozzolan-Cement Mortars for Thermal Retrofit of Heritage Architecture, Developments in the Built Environment 26:100930, 2026.
The energy retrofitting of heritage buildings is constrained by strict requirements on material compatibility, reversibility, and minimal intervention, limiting the use of conventional insulation systems. In this context, lime-based rendering mortars incorporating phase change materials (PCMs) offer a promising solution for enhancing thermal performance while respecting conservation principles. This study investigates the suitability of PCM-enhanced ternary lime-pozzolan-cement mortars through a combined laboratory and field-scale experimental approach, with particular emphasis on real-scale validation under outdoor conditions. [...] Overall, the findings confirm that PCM-enhanced ternary lime-based mortars can provide passive thermal buffering while maintaining compatibility with heritage substrates, supporting their application in conservation-oriented energy retrofitting strategies.
M.H. Nofalah, L. Kyriakou, J.M. Fernández, Í. Navarro-Blasco and J.I. Álvarez, Impact of Vaterite Integration on the Hydration, Microstructure and Performance of Calcined Clay Cements, Scientific Reports 16:20305, 2026.
Vaterite Calcined Clay Cement (VC3) is a novel binder system in which the conventional calcite used in Limestone Calcined Clay Cement (LC3) is replaced with vaterite, a metastable polymorph of calcium carbonate characterized by its higher reactivity and spherical particle morphology. Although initial studies suggest potential benefits, the effects of vaterite on hydration kinetics, fresh-state behavior, and long-term mechanical performance remain insufficiently understood. To address this, eight mortar formulations were developed with 0–15% of vaterite content and 40%-50% Ordinary Portland Cement (OPC) content. Results showed that, in VC3 specimens, vaterite enhanced fresh-state workability and prolonged the induction period of hydration while maintaining long-term reactivity. Although early-age compressive strength was reduced, VC3 mortars exhibited significant strength development over time. At 91 days, the mortar incorporating 15% vaterite and 50% OPC showed a marked increase in strength, reaching 129% of the compressive strength of the LC3 reference mortar. Even formulations with only 40–45% OPC achieved 110–124% of the reference strength. Analysis of the phase assemblage and microstructural analyses confirmed sustained pozzolanic activity, with ongoing portlandite (CH) consumption and the formation of ettringite and carboaluminate phases. These results position VC3 as a promising low-clinker alternative, combining improved fresh-state performance with competitive long-term strength and enhanced sustainability.
Meng, S., Guadagnini, M., Oleng, M., Torelli, G., Hajirasouliha, I., & Pilakoutas, K. (2026). Multiscale elasto-plastic phase-field framework for concrete crack initiation and propagation. International Journal of Mechanical Sciences, 311, 111219.
The fracture behaviour of concrete is governed by complex interactions among aggregates, mortar, pores and interfacial transition zones. This study presents a novel micro‑meso elasto-plastic phase-field modelling framework that captures crack initiation and propagation by explicitly accounting for the mechanical contribution of each constituent phase. A key innovation of the work is the use of numerical homogenisation and Voronoi diagram to derive the effective stiffness and geometric properties of the pore phase, enabling the decomposition of mortar into a mortar solid and pore network while preserving overall material fidelity. The proposed multi-phase formulation, which assigns distinct elastic, plastic and fracture properties to mortar, ITZ, pores and aggregates, is combined with Drucker-Prager plasticity and spectral energy decomposition to represent asymmetric tensile and compressive behaviour. The model is calibrated and validated against experimental data from uniaxial compression tests on mortar and concrete, three-point bending tests, and reinforced concrete beams. The numerical predictions accurately reproduce both load-displacement behaviour and crack evolution. Parametric studies reveal the influence of mesh size, ITZ thickness, porosity and pore width on crack tortuosity and structural capacity. The results demonstrate that the proposed framework provides a significant advancement in linking concrete microstructure to macroscopic fracture behaviour.
E. Çam, L. Kyriakou, J.M. Fernández, Í. Navarro-Blasco, J.I. Álvarez. (2026). Comparative assessment of hemp shiv and basalt fibre reinforcements in lime-based mortars for sustainable building and heritage-compatible applications, Construction and Building Materials, Volume 521, 2026.
The need to enhance both the mechanical resistance and the thermal performance of lime mortars has intensified interest in fibre-based reinforcement strategies, particularly for heritage-oriented and energy-efficient construction. This study evaluates the influence of natural and mineral reinforcements, hemp shiv and basalt fibre, on the fresh state, physical, microstructural, mechanical, and thermal behaviour of three lime-based mortar systems: natural hydraulic lime (NHL), air lime, and a mixed air lime–cement binder. Reinforcements were incorporated at two dosages (1 and 4 wt% of binder) to examine their interaction with distinct binder chemistries and pore structures. Hemp shiv decreased workability and increased open porosity across all mortars, while basalt fibre produced only limited changes in fresh properties. Microstructural variations arose mainly from increased air-void content due to weak binder–fibre adhesion and interfacial gaps. Compressive strength trends reflected these microstructural modifications; natural hydraulic lime mortars achieved the highest values up to 12 MPa, and high-dosage basalt fibre improved long-term strength through crack bridging, whereas hemp shiv reduced strength, particularly at higher dosages, by 21% in NHL mortars and about 60% in air lime-based mortars. Thermal behaviour, however, showed clear benefits across all reinforced mortars: thermal conductivity consistently decreased, with the most significant reductions observed in hemp-shiv mixtures, up to 30%, and in basalt-fibre mortars at low dosage by 45% in NHL mortars and 24% in air lime-based mortars. These improvements highlight the capacity of fibre reinforcements to promote more insulating pore networks while maintaining acceptable mechanical performance. Overall, the findings clarify how organic and mineral fibres modify lime-based matrices and demonstrate their potential for producing thermally efficient, sustainable, and compatible mortars for building and heritage-compatible applications.
M. Davolio, E. Cuenca, D. di Summa, R.P. Borg, L. Ferrara. (2026). On the use of recycled UHPC to reduce cement demand in UHPC mixes: mechanical and durability validation . Journal of Building Engineering, Volume 114, 2026.
Ultra-High Performance Concrete (UHPC) offers superior durability and strength, as compared to ordinary concrete solutions, but its inborn environmental footprint is dictated by high cement content and the environmental impact of raw material extraction, which would require a heavily optimized structural and process design to be levelled off. With the aim of assessing effectiveness of strategies aimed at reducing the embodied carbon footprint of UHPC mixes, this study investigates two recycled UHPCs (R-UHPC) designed by replacing all natural aggregates with crushed UHPC and partially substituting Portland cement (30 %) with recycled material. One mix used ungraded crushed UHPC; the other included additional fine fractions (≤75 μm) obtained through further processing. The partial replacement of cement constitutes a novelty alongside the widely established aggregate replacement in high performance cementitious materials. Both mixes achieved superior compressive strength and comparable flexural strength to the reference UHPC, while demonstrating effective autogenous self-healing under repeated NaCl exposure, with full recovery of crack sealing, sorptivity, strength, and stiffness over six months. However, the mix containing recycled fines showed reduced performance under repeated damage-healing cycles, mainly attributed to its higher water absorption. A cradle-to-gate life cycle assessment using the CML-IA method and a functional unit of 1 m3 – subsequently normalized over long-term compressive and flexural strength – revealed that mechanical performance strongly influences environmental impacts. Notably, the additional processing and increased input volumes required for fine fractions led to higher impacts across all categories. This work lays the foundation for a rational and engineering-wise effective promotion of the circular economy concept in the design and production of highly durable cement-based materials and structures by demonstrating unexplored and effective recycling strategies for UHPC elements at the end of their service life, facilitated by their unaltered condition even after prolonged use.
A. Rubio-Aguinaga, L. Kyriakou, J.M. Fernández, Í. Navarro-Blasco and J.I. Álvarez. (2025). Sustainability of PCM-lime mortars for heritage retrofitting: Carbon footprint and impact on energy demand across climates. Case Studies in Construction Materials, 23, e05294, 2025.
Recent research on PCM–lime mortars has predominantly addressed material-scale behaviour or single-climate cases, with limited integration of embodied carbon and operational energy at the building scale—particularly for heritage envelopes under conservation constraints. To address this gap, the present study develops a climate-resolved, building-scale assessment that couples cradle-to-gate embodied impacts with operational energy effects for PCM-enhanced lime mortars in heritage retrofitting. [...] Simulations reveal that PCM-enhanced mortars can eliminate cooling demands and significantly reduce heating needs. Maximum total carbon footprint reductions were achieved with the bio-based PCM (89.1 %), followed by the 24 °C paraffin PCM (87.2 %) and the 18 °C paraffin PCM (74.6 %), depending on the climate zone. This work provides a comparative assessment of paraffin versus bio-based PCMs, highlighting the importance of climate-PCM compatibility and delivering critical insights into the embodied carbon and long-term environmental impact of these mortars in heritage retrofitting.
Fathi, F., René de Borst, & Torelli, G. (2025). A consistent phase-field-regularised partition of unity method for fracture analysis. Computer Methods in Applied Mechanics and Engineering, 446, 118267.
Recent advancements in phase-field models have significantly reshaped the landscape of fracture mechanics, which was dominated by the partition of unity method in the early 21st century. In this study, we aim to leverage the advantages of the two approaches by adopting a novel phase-field-regularised partition of unity method to improve computational efficiency, robustness and physical consistency. [...] Through numerical examples, including stationary and propagating cracks, mesh refinement studies, and sensitivity analyses of the phase-field length scale, we establish an optimal prescription for the internal length scale based solely on the element size. The examples compare the results obtained via the presented formulations with exact solutions and other numerical techniques, demonstrating the accuracy, conditioning stability, and computational efficiency of the methodology. The proposed methodology thus presents a robust alternative to conventional fracture models, combining key advantages offered by discrete and smeared approaches.
Meng, S., Guadagnini, M., Torelli, G., Hajirasouliha, I., & Pilakoutas, K. (2025). Meso-scale phase-field modelling framework for predicting fracture propagation in concrete. Computer Methods in Applied Mechanics and Engineering, 446, 118281.
Capturing crack development in cementitious materials at the mesoscopic level is crucial for analysing crack patterns and failure mechanisms. This paper introduces a meso‑scale model for concrete that utilizes random packing to generate the geometry and spatial distribution of aggregate, interfacial transition zone (ITZ) and mortar. The Drucker-Prager yield criterion is introduced in this phase-field model to account for the elasto-plastic behaviour of the mortar and the ITZ. The spectral decomposition of the strain tensor is employed to model the asymmetric tension and compression damage behaviour of porous materials. The parameters of the proposed model are calibrated on experimental data obtained from compressive and flexural tests of concrete and mortar specimens, including detailed information on crack initiation and propagation. Finally, the model is validated against data from the literature including complex loading scenarios and stress fields, such as triaxial compression and compression-shear. The predictions show strong agreement with the experimental results, confirming that the proposed methodology effectively captures crack propagation in concrete. This work will lead to more accurate predictions of concrete cracking mechanisms and long-term behaviour.
Meng, S., Li, Y., Hajirasouliha, I., Torelli, G., Guadagnini, M., & Pilakoutas, K. (2025). An innovative method for mesoscale modelling of moisture diffusion in concrete. Cement and Concrete Composites, 155, 105836.
Moisture diffusion influences the durability and long-term performance of concrete and whilst it predominantly occurs via the cement matrix and Interfacial Transition Zone, most existing models consider concrete to be homogeneous. This paper introduces a novel micro-meso model that employs random packing and Voronoi tessellation. Rayleigh-Ritz pore distribution and Brunauer-Skalny-Bodor models are combined to determine the radius and fraction of various pores. The results indicate that relative humidity diffuses faster with increasing temperature, decreasing ambient relative humidity and tortuosity. Ambient relative humidity has a greater influence on diffusion compared to temperature and tortuosity. Numerical and experimental comparisons demonstrate that the proposed methodology effectively captures relative humidity distribution across various scenarios. Furthermore, explicit pore network modelling incorporates key parameters for a more accurate analysis. Integrating the proposed methodology into a fully coupled hygro-mechanical framework can potentially yield more accurate predictions of mechanical behaviour; enhancing the reliability of long-term performance assessments and enabling more durable concrete design.
Trochoutsou, N., Smyl, D., & Torelli, G. (2025). Electro-mechanical behaviour of mortars reinforced with alternative electrically conductive inclusions. Materials and Structures, 58(2), 56.
The incorporation of electrically conductive inclusions in structural materials can impart self-sensing functionalities, making them ideal for structural health monitoring applications. However, the use of more sustainable alternatives and their effect on key engineering properties remain largely unexplored, while the adoption of different testing protocols for the characterisation of electrical/self-sensing properties can lead to different results, thus questioning their reliability, even for existing smart composites. This paper investigates systematically the effect of recycled carbon fibres and graphite powder on the mechanical, electrical, transport properties and piezoresistive performance of cementitious mortars. Virgin carbon fibres, at dosages equivalent to those of recycled fibres, were also examined to establish a performance benchmark. Fibre content ranged from 0.05% to 1% vol., while graphite powder was added as sand replacement at contents varying from 0.3% to 3% vol. The effect of existing testing protocols and electrode layout on the piezoresistive performance was also examined, and the associated limitations and challenges are discussed in detail. The results demonstrate the potential of recycled carbon fibres as a cost-effective alternative in smart applications, without compromising electrical and piezoresistive performance. The use of 0.25%vol. of recycled or virgin carbon fibres was found to provide the desirable synergy between structural performance, cost and self-sensing properties, yielding a 50–60% increase in flexural strength, and good piezoresistivity with a gauge factor of 90–110. In contrast, the use of graphite powder resulted in composites with poor self-sensing ability even at the highest content examined (3%vol.), also accompanied by a reduction in compressive strength up to 33%.
A. Rubio-Aguinaga, L. Kyriakou, J.M. Fernández, Í. Navarro-Blasco and J.I. Álvarez, (2025). Microstructural analysis of bio-based PCM-enhanced lime mortars: Durability and energy efficiency for sustainable buildings. Construction and Building Materials, 481:141569.
The development of energy-efficient and sustainable building materials is crucial in reducing energy consumption and environmental impact in the construction sector. This study presents a novel approach by integrating a bio-based microencapsulated phase change material (PCM) into air lime-based mortars, aiming to enhance thermal performance while ensuring durability and mechanical integrity. Unlike conventional PCM-enhanced mortars, this research emphasizes the use of renewable, biodegradable PCMs derived from agricultural sources, reducing reliance on fossil-based alternatives. The optimized formulations were designed to function as rendering mortars, balancing workability, adhesion, and durability for application in both modern and historic buildings. A thorough microstructural investigation through SEM and MIP revealed that controlled PCM dosages (5–10 %) preserved matrix cohesion, whereas higher PCM contents (20 %) led to increased porosity. Thermal performance assessments, including DSC and hotbox experiments, confirmed the effectiveness of the PCM-enhanced mortars in regulating temperature fluctuations and improving energy efficiency. Additionally, durability testing demonstrated the superior resistance of PCM-modified mortars to freeze-thaw cycles and salt crystallization, while cyclability analyses confirmed their long-term thermal stability over multiple phase transitions. These findings establish bio-based PCM-enhanced lime mortars as a resilient, eco-friendly solution for sustainable construction, contributing to climate-responsive design and energy-efficient buildings.
I. Karatasios, S. Papaioannou, E. Tziviloglou, V. Kilikoglou. (2024). Effect of shell composition on watertightness and mechanical performance of cement-based capsules used as self-healing additives of cement. Developments in the Built Environment, (20).
The aim of this work is the development of cementitious macro-capsules for self-healing cement and concrete materials. Emphasis is placed on shell properties, including size, thickness, strength, and volume to active component ratio. This enhancement is aimed at protecting the healing agent and ensuring adequate reactivity upon crack formation, surpassing survivability considerations. To this direction, core/shell particles have been produced following the pan-coating method, while different types and concentrations of setting acceleration solutions for the shell stabilization were studied. The formation of core-shell capsules encompasses the formation a spherical core through agglomeration, followed by simultaneous spraying of cement powder and a setting acceleration solution for the shell formation, under continuous rotation. The microstructural characteristics of the shell were studied through scanning electron microscopy (SEM), while the reactivity of the protected core (reactive agent) inside the hardened mortar mixtures was evaluated using thermogravimetric analysis (TGA). Moreover, the crushing load of the capsules under compression and their survivability during mixing process were examined and interpreted in relation to their diameter, circularity, and shell thickness. The results revealed the ability of the encapsulation methodology proposed to tailor the shell properties and modify the capsule properties so as satisfy the requirements of different applications. The use of setting accelerators during shell formation proved essential for enhancing the density and the strength of the shell layer. As a consequence, this leads to macro-scale capsules with elevated survivability rate and core reactivity.
Rubio-Aguinaga A, Fernández JM, Navarro-Blasco I, Alvarez JI. (2024). Air lime renders with microencapsulated phase change materials: assessment of microstructural and thermal properties. Construction and Building Materials, 452: 138862, 1-19. DADUN
Microencapsulated phase change materials (PCMs) have been successfully integrated into air lime-based rendering mortars to enhance thermal properties, aiming to boost the thermal efficiency of the buildings in which are applied. Two microencapsulated PCMs, with melting points at 18℃ and 24℃, were seamlessly introduced into fresh rendering mortars in varying proportions (5 %, 10 %, and 20 % by weight of lime), in formulations that include different chemical additives, such as a superplasticizer (polycarboxylate ether) and an adhesion enhancer (starch-based additive). In some mixes, metakaolin (MK) was also added as a mineral admixture. Starch addition was seen to promote the formation of aragonite and vaterite (calcium carbonate polymorphs), facilitating the smooth integration of microcapsules within the lime matrix. Hotbox simulations with tested materials containing as low as 0.01–0.04 g of PCM per gram of dry mortar, yielded outstanding energy efficiency values (822.4 and 732.8 kJ/m2, respectively, for PCMs with melting points at 18℃ and 24℃). Temperature attenuations of up to 6.1°C during the heating stage and up to 3.9°C during the cooling stages were observed. This outcome not only emphasizes the potential for enhancing thermal efficiency through PCM incorporation into air lime renders but also hints at a remarkable future for energy-efficient construction materials.
Ria L. Mitchell, Andy Holwell, Giacomo Torelli, John Provis, Kajanan Selvaranjan, Dan Geddes, Antonia Yorkshire, Sarah Kearney. (2024). Cements and concretes materials characterisation using machine-learning-based reconstruction and 3D quantitative mineralogy via X-ray microscopy. Journal of Microscopy.
3D imaging via X-ray microscopy (XRM), a form of tomography, is revolutionising materials characterisation. Nondestructive imaging to classify grains, particles, interfaces and pores at various scales is imperative for our understanding of the composition, structure, and failure of building materials. Various workflows now exist to maximise data collection and to push the boundaries of what has been achieved before, either from singular instruments, software or combinations through multimodal correlative microscopy. [...] Here, we apply three AI and machine-learning-based reconstruction approaches to cements and concretes to assist with image improvement, faster throughput of samples, upscaling of data, and quantitative phase identification in 3D. We show that by applying advanced machine learning reconstruction approaches, it is possible to (i) vastly improve the scan quality and increase throughput of ‘thick’ cores of cements/concretes through enhanced contrast and denoising using DeepRecon Pro, (ii) upscale data to larger fields of view using DeepScout and (iii) use quantitative automated mineralogy to spatially characterise and quantify the mineralogical/phase components in 3D using Mineralogic 3D. These approaches significantly improve the quality of collected XRM data, resolve features not previously accessible, and streamline scanning and reconstruction processes for greater throughput.
Rubio-Aguinaga, A.; Fernández, J.M.; Navarro-Blasco, Í.; Álvarez, J.I. Study on the Interaction of Polymeric Chemical Additives with Phase Change Materials in Air Lime Renders. Polymers 2024, 16, 1121.
The interaction of microencapsulated phase change materials (PCMs) with polymeric chemical additives in an air lime binding matrix was studied. These polymer-based additives included an adhesion booster (derived from starch) and a superplasticizer (polycarboxylate ether). Two different PCMs with melting points of 18 °C and 24 °C were assayed. The microcapsules were composed of melamine, with paraffin-based PCM cores. Measurements of zeta potential, particle size distribution, adsorption isotherms, and viscosity analyses were performed to comprehend the behavior of the polymer-based additives within the air lime matrix and their compatibility with PCMs. Zeta potential experiments pointed to the absence of a strong interaction between the lime particles and the microcapsules of PCMs. [...]
Conferences
R.P. Borg, A. Koppen, L. Piarulli, P. Moraitou, E. Messinas, J. Jares (2026). Resilient and adaptive renovation towards net-zero carbon heritage buildings. , RILEM 80th RILEM Week 2026, September 5-11.
The SINCERE project aims to strengthen the resilience of modern and industrial heritage buildings and reduce carbon emissions in restoration. This project integrates five pilot sites to test and demonstrate novel and advanced materials, including hempcrete, ultra-high-performance concrete, and textile-reinforced concrete. Additional materials include phase change materials, corrosion inhibitors, self-healing agents, radiative cooling paints, and building integrated photovoltaics (BIPV). The project also utilises digital technologies and sensor monitoring systems. [...] The SINCERE solutions specifically address the different needs of the buildings, tailored to the climate conditions, the current state, materials, and requirements to sustain current use or intended adaptive reuse. Building benefits are expected, such as improved occupant comfort, equipment protection, and energy perfor-mance without compromising the heritage character. These statements will be supported with data as novel materials are monitored through sensors. The implementation and data monitoring will confirm the scalability and transferability of SINCERE solutions to modern and industrial heritage buildings. The project validates a retrofit strategy that integrates structural, thermal, energy, and con-servation objectives.
Torelli, G., & Fathi, F. (2026). Automated Discovery of Heat Conduction Constitutive Laws. 17th World Congress on Computational Mechanics (WCCM) 10th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS) 19 - 24 July 2026, Munich, Germany.
Fathi, F., de Borst, R., & Torelli, G. (2026). Mutual Enhancement in Blending Partition of Unity and Phase-Field Methods. 17th World Congress on Computational Mechanics (WCCM) 10th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS) 19 - 24 July 2026, Munich, Germany.
Soltani, A., Fathi, F., de Borst, R., & Torelli, G. (2026). Automatic Discovery of Interpretable Free Thermal Strain Models. 17th World Congress on Computational Mechanics (WCCM) 10th European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS) 19 - 24 July 2026, Munich, Germany.
Soltani, A., Fathi, F., de Borst, R., & Torelli, G. (2026). Automated Discovery of Interpretable Thermo-Mechanical Constitutive Laws. 20th European Mechanics of Materials Conference, 27-29 May 2026 Location Florence, Italy.
Soltani, A., Fathi, F., de Borst, R., & Torelli, G. (2026). Automatic Discovery of Thermoelastic Constitutive Laws Using Full-field Temperature, Displacement, and Total Reaction Forces. UKACM 2026 Conference, 8-10 April 2026, University of Liverpool, Liverpool, UK.
Meng, S., Fathi, F., Piarulli Paz, L., Cuenca, E., Ferrara, L., & Torelli, G. (2026). Shrinkage-Induced Cracking in Low-Carbon Repair Overlay Mortars: Analytical and Numerical Assessment. Structural Concrete 2050: Towards Carbon Neutrality, AI Design, and Robotic Construction: Proceeding of the 7th Fib Congress Held in Lisbon, Portugal 15-19 June 2026, 1361–1370.
L. Kyriakou, J.M. Fernández, Í. Navarro-Blasco and J.I. Álvarez. (2025). Salt Weathering Performance of Ternary Lime-Pozzolana-Cement Renders with Microencapsulated and Silica-Supported Phase Change Materials, SWBSS 2026 - 6th International Conference on Salt Weathering of Buildings and Stone Sculptures, 19-21 February 2026, Budapest, Hungary.
Haik, R., Lazar, D., & Peled, A. (2025). Hempcrete as low carbon solution for thermal retrofitting of buildings, Proceedings of the Carbon Conscious Concrete Symposium (C3 Symposium 2025). Chicago, IL: Purdue University e-Pubs.
Thermal mortars are developed with hemp shives and pozzolans for thermal retrofitting of cultural heritage buildings, including concrete architecture from the 50s. The goal is to improve the thermal performance of the building, while reducing the carbon footprint. This research is within the framework of European Union’s Horizon 2020 (Sincere). A range of mixtures were developed based on standard mortar for plaster, as a reference. The research investigates the possibility of partly replacing the cement with pozzolans, as well as the sand in the mortar with fine hemp shives, to obtain lower EE and EC of the mixture, as compared to the reference. Replacing 60% of the cement with pozzolans improves the compression strength. Replacing the sand with several percentages of fine hemp shives reduces the compression strengths, while expected to significantly improve the thermal conductivity of the mortar.
E. Messinas Modern Cultural Heritage Sustainable Renovation: The SINCERE Horizon program pilot site of a Brutalist case study , Conference on Cultural Heritage and New Technologies (CHNT), 3-5 November, 2025, Vienna, Austria.
The SINCERE pilot site of Building 3 at the Holon Institute of Technology (HIT) was built in 1972 in the Brutalist style. It is characteristic of the style, by the exposed reinforced concrete and distinct geometric forms. The pilot interventions include thermal insulating mortars, radiative cooling coatings and BIPVs in the glazed roof surfaces. Through H-BIM/H- Digital Twin tools the interventions will be evaluated for energy conservation and production, maintenance and overall performance. The educational context of the HIT campus, in collaboration with the SINCERE academic partners, provides opportunities to engage the academic community in the installation, monitoring evaluation and dissemination processes, and to make students more aware of modern cultural heritage and technological solutions for its preservation and performance optimization.
E. Tziviloglou, V. Kilikoglou, I. Karatasios. (2025). Parametric design of self-healing admixtures for repair mortars of 20th century historic buildings, Book of extended abstracts, pp. 593-596, HMC 2025 – 7th Historic Mortars Conference, 2-4 September 2025, Padova, Italy.
This work focuses on development of core–shell inorganic admixtures for all types of repair mortars, which autonomously seal cracks when damage occur. What distinguishes this system is the ability for parametric design of admixtures, including capsule size, shell properties, core composition and affinity with different mortar matrices, able to meet both technical and aesthetic demands of repair mortars for preserving 20th century architectural heritage.
R. Paul Borg, I. Semenov, L. Piarulli, I. Karatasios, E. Tziviloglou, J. Jares, N. Dasakli, E. Messinas. (2025). Innovative mortar applications for the retrofitting of modern heritage buildings, Book of extended abstracts, pp. 609-612, HMC 2025 – 7th Historic Mortars Conference, 2-4 September 2025, Padova, Italy.
This research highlights how advanced mortars can enhance energy efficiency and material resilience while maintaining architectural authenticity. The results are intended to underscore the importance of specific material design, passive energy strategies, and scalable monitoring tools in achieving sustainable heritage retrofitting, contributing to a toolkit for conservation.
R. Paul Borg, I. Semenov, L. Ferrara, I. Karatasios, E. Tziviloglou. (2025). Durability and compatibility requirements of repair mortars for structural retrofitting of 20th-century built heritage, Book of extended abstracts, pp. 647-648, HMC 2025 – 7th Historic Mortars Conference, 2-4 September 2025, Padova, Italy.
The structural retrofitting of 20th-century built heritage presents unique challenges due to the materials and construction techniques used during this period. Reinforced concrete and masonry became dominant, requiring specific approaches for repair and restoration. One of the key concerns is the selection of appropriate repair mortars to ensure both durability and compatibility with the original structure. Inappropriate choices can lead to early degradation, mechanical instability, and loss of historical authenticity. Proposed research focuses on the durability and compatibility requirements of repair mortars for the structural retrofitting of 20th-century built heritage, ensuring material selection, performance assessment, and long-term durability.
D. Kolokotsa, F. Lygerakis, L. Kyriakou, L. Pirone, H. Abbasi, S. Converso, R. Haik, A. Peled, J. Ignacio Álvarez, V. Dallas, M. Vlachogianni, T. Sfetsos, E. Tziviloglou, I. Karatasios. (2025). HBIM and BEM driven design and selection of repair mortars for enhancing energy performance of historic buildings under climate change, Book of extended abstracts, pp. 653-655, HMC 2025 – 7th Historic Mortars Conference, 2-4 September 2025, Padova, Italy.
This study aims to address the data-driven decision making and materials selection for the thermal retrofitting of historic buildings, both at material/mortars scale and building/structure scale, through the use of Building Information Modeling (BIM) and Building Energy Modelling (BEM) tools.
P. Antoniadis, M. Bakari, N. Dasakli, J. Jareš, E. Messinas, and A. Šmehilová. (2025). Building for the people - the role of citizen science for the preservation of built heritage, Book of extended abstracts, pp. 649-651, HMC 2025 – 7th Historic Mortars Conference, 2-4 September 2025, Padova, Italy.
The SINCERE project develops innovative renovation materials and technologies, experimenting with a wide range of low CO2 restoration mortars trying to balance a set of trade-offs regarding their thermal conductivity, compressive strength, cost, permeability, reversibility, recyclability, workability, and self-healing capacity, among others. Although finding the right balance between all these qualities is at its core a technical task, making the final decisions on the right combination of materials to be applied for a specific renovation project highly depends on the local context and the role of citizen participation in the process can be very useful. To meaningfully engage citizens in such a complex task, the SINCERE project introduces an innovative citizen science methodology, the Talking Buildings Game, a process of incremental engagement with a building based on the idea of impersonation of non-human entities, drawing inspiration from Bruno Latour’s Actor-Network-Theory.
M.H. Nofalah, L. Kyriakou, J.M. Fernández, Í. Navarro-Blasco and J.I. Álvarez. (2025). The Durability of Vaterite Calcined Clay Repairing Mortars: Another Sustainability Aspect in Innovative Low-CO2 Materials, Book of extended abstracts, pp. 639-642, HMC 2025 – 7th Historic Mortars Conference, 2-4 September 2025, Padova, Italy.
This study aims to address this knowledge gap by investigating VC3’s durability relative to LC3 and OPC. Experimental mortar samples were prepared, including a reference OPC mortar and mortars where calcite was progressively replaced by vaterite at increments of 0%, 5%, 10%, and 15%. The materials’ performance was evaluated based on key parameters: mechanical strength, capillary water absorption, and sulfate resistance. This comprehensive evaluation provides insights into the long-term behavior of VC3, contributing valuable data towards advancing sustainable cement technologies and addressing both environmental and structural challenges.
E. Çam, L. Kyriakou, J.M. Fernández, Í. Navarro-Blasco and J.I. Álvarez. (2025). Enhancing the Properties of Lime Mortars with Volcanic Ash and Hemp Shiv: A Sustainable Approach for Restoration Applications, Book of extended abstracts, pp. 371-374, HMC 2025 – 7th Historic Mortars Conference, 2-4 September 2025, Padova, Italy.
This study aims to investigate the effects of volcanic ash and hemp shiv additions on the fresh and hardened properties of air lime and natural hydraulic lime mortars, highlighting their suitability for sustainable and heritage-compatible restoration applications.
A. Rubio-Aguinaga, L. Kyriakou, J.M. Fernández, Í. Navarro-Blasco and J.I. Álvarez. (2025). Impact of microencapsulated PCMs on lime mortars: thermal and durability assessment, Book of extended abstracts, pp. 631-634, HMC 2025 – 7th Historic Mortars Conference, 2-4 September 2025, Padova, Italy.
This study evaluates the performance of lime mortars integrated with microencapsulated PCMs, aiming to establish them as a viable solution for sustainable, durable, and resilient building materials.
L. Kyriakou, R. Haik, A. Peled, E. Tziviloglou, I. Karatasios, J.M. Fernández, Í. Navarro-Blasco and J.I. Álvarez. (2025). Lime-based Mortars for Thermal Retrofitting of Historic Buildings – Key Challenges for Field Application, Book of extended abstracts, pp. 643-646, HMC 2025 – 7th Historic Mortars Conference, 2-4 September 2025, Padova, Italy.
This research supports the broader goal of integrating innovative building materials into heritage conservation strategies, ensuring that interventions are compatible to the original fabric of historic buildings and do not accelerate substrate degradation or disrupt historical aesthetics.
M.H. Nofalah, L. Kyriakou, J.M. Fernández, Í. Navarro-Blasco and J.I. Álvarez. (2025). The Influence of Metakaolin to Vaterite Ratio on the Properties of Vaterite Calcined Clay Cement: Microstructure, and Mechanical Performance. , ICSBM 2025 – 4th International Conference on Sustainable Building Materials, 10-13 August 2025, Eindhoven, The Netherlands.
This study examines Vaterite Calcined Clay Cement (VC3) as a sustainable binder, focusing on how the metakaolin-to-vaterite (MK/V) ratio influences workability, microstructure, and mechanical properties. By addressing this gap, this research contributes to optimizing VC3 formulations and advancing low-carbon cement technology.
E. Çam, L. Kyriakou, J.M. Fernández, Í. Navarro-Blasco and J.I. Álvarez.(2025). Investigating the Influence of Hemp Shiv Size on Air Lime-Based Mortars for Sustainable Restoration Applications. , ICSBM 2025 – 4th International Conference on Sustainable Building Materials, 10-13 August 2025, Eindhoven, The Netherlands.
Lime mortars are preferred in conservation work for their compatibility with heritage buildings. However, enhancing the performance of lime mortars while maintaining their compatibility and sustainability remains a challenge. The incorporation of natural reinforcements, such as hemp, specifically its woody core known as hemp shiv (a by-product of hemp fibre harvesting) offers a promising solution. Characterized by low density, low thermal conductivity, and high-water absorption capacity, hemp shiv is advantageous for sustainable construction applications. This study evaluates the effects of hemp shiv sizes as reinforcement in air lime-based mortars for restoration. Unlike their widespread use in hempcrete, in this study hemp shives are used in smaller quantities similar to the incorporation of fibres into mortars, facilitating targeted improvements in mechanical strength, thermal properties, and workability without significantly altering mortar’s density or texture.
A. Rubio-Aguinaga, L. Kyriakou, J.M. Fernández, Í. Navarro-Blasco and J.I. Álvarez. (2025). Silica-Supported Form-Stable Phase Change Materials for Enhancing Thermal Performance in Lime Mortars. , ICSBM 2025 – 4th International Conference on Sustainable Building Materials, 10-13 August 2025, Eindhoven, The Netherlands.
As concerns about sustainability and energy efficiency in the construction sector grow, lime-based mortars present a promising alternative due to their lower carbon footprint compared to conventional mineral binders. These mortars are not only environmentally friendly but also highly compatible with heritage conservation, making them ideal for the restoration of historical buildings. This study investigates the incorporation of form-stable phase change materials (PCMs), specifically silica-supported PCMs, into lime mortars to improve their thermal performance, enhancing both energy efficiency and thermal comfort. PCMs absorb and release heat during phase transitions, reducing the need for active climate control systems and enhancing building thermal efficiency. The use of form-stable, silica-supported PCMs helps prevent material leakage during thermal cycling, ensuring greater long-term stability and reliability. This study focuses on the mechanical, thermal, and microstructural properties of lime-based mortars with silica-supported PCMs to assess their potential for improving energy efficiency and sustainability in construction applications.
E. Batziou, N. I. Dourvas, K. Ioannidis, S. Diplaris, S. Vrochidis, I. Kompatsiaris. (2025). Digital Twin Development for Cultural Heritage Buildings: A Multimodal Approach to Simulating Energy Performance, in Proceedings of the ISIM Workshop at ACM IMX 2025, ACM, 2025.
Cultural heritage buildings represent invaluable historical and architectural assets, but their preservation often conflicts with the need for modern energy efficiency. This paper presents a novel framework for digital twin development that adopts a multimodal approach to provide an open-source environment of a CH building with the goal to simulate and optimize energy performance in heritage structures. By integrating diverse data modalities, such as structural analysis, environmental monitoring, and multimedia documentation, the proposed digital twin provides a comprehensive, dynamic representation of the building’s energy behavior. This approach enables more accurate simulations of energy performance, facilitating informed decision-making for sustainable retrofitting while respecting the unique constraints of cultural heritage conservation. The application of this framework in a real case study demonstrates the potential of multimodal digital twins to bridge the gap between preservation and energy efficiency, to increase immersiveness and to highlight their role in advancing sustainable management practices for heritage sites. The findings underscore the transformative potential of digital twin technology in fostering sustainable, data-driven solutions for cultural heritage conservation.
A. Vassiliades, A. I. Karageorgiadis, E. Batziou, S. Diplaris, E. A. Stathopoulos, N. Dourvas, K. Ioannidis, S. Vrochidis, I. Kompatsiaris. (2025). Optimizing Carbon Footprint & Energy Performance for the Sustainability of Historic Buildings using Knowledge Graphs & Digital Twins., in Proceedings of the 3rd Ιnternational Workshop on Knowledge Graphs for Sustainability (KG4S), Portoroz, Slovenia, June 1-2, 2025.
Cultural heritage preservation is crucial for climate resilience and sustainable development, requiring innovative tools, materials, and adaptive renovation to mitigate climate risks, reduce emissions, and enhance sustainability in line with the EU Green Deal and UN Sustainable Development Goals. This paper presents ongoing work integrating Knowledge Graphs, Digital Twins, and Building Information Modeling (BIM) to optimize the carbon footprint and energy performance of historic buildings through innovative restoration materials, energy harvesting technologies, and socially-driven approaches, aligning with net-zero-carbon goals. We propose a pipeline where a Digital Twin, incorporating a BIM model, simulates a historic building’s virtual representation to evaluate how different materials impact energy consumption and sustainability. The Knowledge Graph stores historical, real-time (sensor-based), and predicted weather data, enabling the Digital Twin to assess weather-driven energy performance variations and determine optimal material choices. As part of the EU-funded SINCERE project, this system provides a data-driven decision-making framework for stakeholders, supporting restoration, operation, and long-term sustainability planning for Built Cultural Heritage.
M.H. Nofalah, L. Kyriakou, J.M. Fernández, Í. Navarro-Blasco and J.I. Álvarez, (2025). The use of Vaterite in Calcined Clay Cement Binders for Sustainable Production. CEES 2025 – 3rd International Conference on Construction, Energy, Environment and Sustainability, 11-13 June 2025, Bari, Italy.
Wattad, A., Haik, R., & Peled, A. (2025). Low carbon footprint textiles for concrete reinforcement, In M. Briffaut & J. M. Torrenti (Eds.), Concrete Structures: extend lifetime, limit impacts – Proceedings of the 2025 fib International Symposium (pp. 1457-1463). Antibes, France: fib (The International Federation for Structural Concrete).
E. Tziviloglou, C. Stentoumis, J. I. Alvarez, E. Stathopoulos, S.Diplaris, A. Sfetsos, D. Vlachogiannis and I. Karatasios. (2024). Resilient and adaptive renovation of 20th century buildings towards net-zero carbon built heritage – The approach of SINCERE research project. MONUBASIN 2024 .
SINCERE is European collaborative research project, which highlights the significance of Built Cultural Heritage and develops a variety of tools to minimize its carbon footprint and enhances the energy efficiency in historical buildings, through the use of innovative, sustainable, and cost-effective restoration materials, energy harvesting technologies, ICT tools, and socially innovative approaches (Fig.1). The project employs a multi-scale approach, addressing material, building, neighborhood, and city levels, focusing on the structure, external envelope, and transparent elements of buildings. SINCERE offers a range of sustainable restoration options evaluated through Digital Twin (DT) tools tailored to the needs of historical buildings. This enables the selection of optimal solutions for structural and thermal retrofitting, and the planning of necessary adaptation measures for addressing the climate change challenges and enhancing energy efficiency.
Christos Stentoumis, Minas Katsiokalis, Panagiotis Bikiris, Nikos Karantakis. (2024). Engineering a BIM-based mixed reality application for the life-cycle management of buildings. XR SALENTO 2024.
Building stock is a significant capital for every society and signifies its prosperity, while, on the other hand, it has a significant life␂cycle cost for its design, construction, operation, and demolition or reno␂vation phases. Simultaneously, buildings have a huge environmental im␂pact because of the energy and natural resource consumption involved in construction and operation. Hence, efficient life-cycle building manage␂ment is important to reduce resource usage and improve human comfort. Building information modelling (BIM) has gradually gained attention in recent decades and is widely considered a key to digitising and optimis␂ing the building life cycle. Yet, there are important challenges in the standardisation of methodologies, interoperability of solutions and data exchange, as well as the usability of BIM-related solutions. Moreover, modern or renovated buildings produce extensive real-time data on top of the static data organised in BIM. It is commonly accepted that most professionals in the field do not have access to the critical static or dy␂namic data that accompany a building project. In this research and in␂novation work, we propose an approach for openness and interoperability of building data across the different phases of a building’s life cycle via a BIM-based mixed reality platform.
A. Rubio-Aguinaga, J.M. Fernández, I. Navarro-Blasco and J.I. Alvarez. (2024). Green Way of Improving the Thermal Efficiency of Mortars by the Addition of Biobased Phase Change Materials. In Proceedings of P.B. Lourenço, M. Azenha and J.M. Pereira (Eds.) "SUBLime Conference 2024 - Towards the Next Generation of Sustainable Masonry Systems: Mortars, Renders, Plasters and Other Challenges”. MATEC Web Conf. 403 03007 (2024). Funchal, Madeira, Portugal, November, 2024.
The thermal efficiency of air lime-based mortars was improved by directly integrating varying amounts (5 wt. %, 10 wt. %, and 20 wt. %) of a microencapsulated biobased phase change material (PCM) into the fresh mortars. This PCM is made of vegetable oils and other organic wastes from the agri-food sector. The mortar formulation was optimized by adding different chemical additives and mineral admixtures. The mortar formulation was meticulously designed to produce rendering mortars that are easily workable, crack-free, and fully adherent for use in building envelopes. Positive outcomes in thermal efficiency tests have demonstrated the ability of these materials to store thermal latent energy, offering an environmentally friendly alternative to enhance the thermal comfort of building inhabitants.
A. Rubio-Aguinaga, L. Kyriakou, J.M. Fernández, Í. Navarro-Blasco and J.I. Alvarez. (2024). Optimized Phase Change Material-Enhanced Lime Renders for Energy-Efficient Building Envelopes: Thermal and Durability Characterization. 3rd International Conference on Green Construction (ICGC2024) Córdoba, Spain, 21-24/10/2024. Oral Presentation.
Posters
P. Antoniadis The Building Stories Platform. Cultural heritage buildings in dialogue, for sustainable preservation and use, Conference on Cultural Heritage and New Technologies (CHNT), 3-5 November, 2025, Vienna, Austria.
Meng Ren (2026). The Development of Halide Double Perovskites. Poster at 2026 Materials Research Society (MRS) Spring Meeting & Exhibit.
F. Wang, F. Ji, and F. Gao (2025). The Development of Halide Double Perovskites. Oral presentation in EM-NANO 2025 – Organic and Inorganic Electronic Materials and Related Nanotechnologies.
E. Çam, L. Kyriakou, J.M. Fernández, Í. Navarro-Blasco and J.I. Álvarez. (2025). Optimizing the Use of Basalt Fiber in Lime-Based Mortars for Heritage Applications, , poster, HMC 2025 – 7th Historic Mortars Conference, 2-4 September 2025, Padova, Italy.
E. Çam, L. Kyriakou, J.M. Fernández, I. Navarro-Blasco and J.I. Alvarez. (2024). Optimization of Air Lime Concrete and Air Lime-based Ternary Mixtures with Sustainable Additives for Enhanced Performance in Heritage Buildings. 3rd International Conference on Green Construction (ICGC2024) Córdoba, Spain, 21-24/10/2024. Poster Presentation.
M.H. Nofalah, L. Kyriakou, A. Rubio-Aguinaga, J.M. Fernández, Í. Navarro-Blasco and J.I. Alvarez. (2024). Veterite Calcined Clay Cement (VC3) as a Low-Carbon Solution. 3rd International Conference on Green Construction (ICGC2024) Córdoba, Spain, 21-24/10/2024. Poster Presentation.