This study presents an experimental investigation of the mechanical behaviour of an earthen masonry system composed of cement-free stabilised compressed earth blocks (CEBs) and earthen mortar. The test program included compressive strength tests on individual masonry components, shear bond tests under varying pre-compression levels, and compressive strength tests on wall elements with horizontal and inclined bed joints. The results show that strength of a CEB does not allow for a prediction of the masonry strength. The strength test of a single CEB leads to an overestimation and interactions between units and mortar influence structural response. The initial shear strength value deducted from shear bond tests shows considerable variation depending on the precompression levels considered for evaluation, limiting the suitability for deriving design parameters. In contrast, wall tests with inclined bed joints provide a more consistent representation of the combined normal–shear stress state and allowed reliable assessment of strength and failure mechanisms. A pronounced reduction in compressive strength was observed with increasing bed joint inclination, followed by a plateau up to the internal friction angle and a subsequent drop to very low strength levels corresponding to sliding failure. This behaviour is comparable to that observed in conventional masonry with fired bricks. The findings indicate that established design approaches, such as SIA 266, may be applicable to earthen masonry, provided material-specific aspects are considered. Further investigations on additional diverse earthen raw materials are required to generalise the results.
The Letter sets out the basis for including a contribution from liquid-water film flow to the so-called water vapour permeability [WVP] of porous inorganic materials. In this, the film thickness is derived from the water vapour sorption isotherm. A regression model is obtained for the dependence of the WVP resistance factor on the humidity. The model is tested against two published datasets. It is noted that available data are scarce, and that new precise measurements of the relation between the WVP and humidity are now required.
Over the past decades, molecular simulations have become a central tool in understanding the fundamental physico-chemical processes in cement-based materials that in turn enable rational design and development of cementitious systems and chemical admixtures for practical applications. Despite the breadth of work, approaches remain heterogeneous. Different research groups employ varied atomic models, force fields, and simulation protocols, often leading to discrepancies , inconsistencies preventing direct comparisons of different results, difficulties in reproducibility, and lack of systematic multiscale validation frameworks which can connect atomistic predictions with meso- and macroscale experiments. The RILEM TC ASM Atomistic Simulations for Cement-Based Materials: Recommendations and Link to Experiments has been established to address these issues by reviewing existing modeling practices, establishing recommended protocols, and creating open-access resources to support both academic and industrial communities.
At present, Japan—similar to many other countries—is undertaking government-supported research and development aimed at transitioning the cement and concrete sectors toward carbon neutrality and a circular economy. This study introduces the approaches adopted by Japan’s cement industry, which operates under unique geological conditions with limited domestic resources, as well as the initiatives pursued within the concrete sector. Because Japan has emphasized resource and energy efficiency since the oil crisis of the 1970s, background information on research and development originally conducted to reduce resource consumption during that period is also incorporated. Although carbon neutrality is a global challenge, each country faces distinct historical and contextual constraints, including geological and resource-related boundary conditions. Research and development efforts must therefore be tailored to national circumstances. In this respect, Japan’s experience is presented here as an illustrative case.
Recycled aggregate concrete (RAC) has emerged as a practical route toward low-carbon construction, offering clear environmental advantages by reducing both natural resource consumption and waste generation. The incorporation of recycled aggregates in concrete results in the coexistence of multiple interfacial transition zones (MITZ), which have significant influence on the mechanical performance, durability and functional properties of RAC. However, the formation and performance evolution of MITZ and its influence on performance of RAC remain insufficiently understood. To achieve a better understanding of ITZs in RAC , this Technical Committee (TC) will focus on (1) investigating the formation mechanisms and damage evolution of MITZ, (2) characterizing the anisotropic and heterogeneous characteristics of MITZ across different scales, (3) exploring the key variables on ITZ performance, (4) quantifying the influence of MITZ on the macro properties of RAC, (5) developing innovative technologies to strengthen MITZ, and (6) establishing quantitative models for MITZ evolution.
This contribution presents an overview of the current literature and application potential of carbon isotope analysis in cementitious systems. Stable carbon isotope ratios (¹³C/¹²C) offer powerful insights for tracking carbonation processes, especially in the context of carbonation hardening and the characterization of recycled concrete fines. Isotope methods can help determine the extent of carbonation and to distinguish between naturally formed carbonates and those resulting from enhanced carbonation by fossil CO2. This approach offers a valuable tool in circular construction strategies. Alongside published studies, we highlight recent experimental work that further demonstrates potential applications of this method. However, to fully exploit carbon isotopes as a diagnostic tool, several questions remain open. In particular, isotope fractionation during carbonation is not yet fully understood. Key factors of influence include temperature, pH, relative humidity, porosity of the carbonated material and the isotope composition of the CO₂ source. Moreover, differences between aqueous and gaseous carbonation must be evaluated, as they may result in different isotope fractionation. Understanding these fractionation mechanisms is essential to establish robust interpretation frameworks for isotope-based approaches in cement and concrete research and applications.
The construction sector is a major contributor to CO2 emissions, responsible for approximately 37% of global and 23% of Switzerland’s total emissions. Addressing this substantial carbon footprint requires innovative and sustainable materials, advanced construction techniques, and comprehensive stakeholder engagement. This paper discusses the key challenges and opportunities in transitioning towards reduced carbon emissions within the construction sector, focusing on the Swiss industry and road bridges as a case study. An extensive dataset of Swiss road bridge infrastructure is assessed herein to understand the current state in Switzerland. An engineering-oriented critical review of high-performance materials such as non-metallic reinforcements, lower impact concrete mixtures and timber products is made in comparison to established construction materials. Circular principles and design for disassembly are explored as strategies for reducing environmental impact. This paper identifies the critical role of availability of early-stage information regarding environmental impact, standardization of emerging materials and techniques, and stakeholder engagement in driving the construction sector towards practices with reduced carbon emissions. Emphasis is put on the requirements and alternatives for achieving reduced carbon emissions in newly constructed bridges, while the potential for extending the service life of existing bridges and its importance for achieving net-zero infrastructure goals is acknowledged but not explored.
This paper examines the influence of commercially available nano silica (NS) admixtures on salt ingress and reaction in mortar. A series of mortar mixtures at dosages ranging from 2.6 to 41.8 mL/kg were tested using isothermal calorimetry (IC), thermogravimetric analysis (TGA), low temperature differential scanning calorimetry (LTDSC), and chloride profiling. Thermodynamic modeling was used to support the experiments. IC showed that the heat of hydration was slightly higher (2-3%) than the reference mixture when the NS admixtures were used. TGA indicated up to 18% reduction in calcium hydroxide at low admixture concentrations (2.6 to 7.8 mL/kg), which is greater than the reduction that would be expected due to pozzolanic reactions alone. At higher admixture dosages (above the recommended dosages), the calcium hydroxide contents were similar to or higher than those of the reference mixture. LTDSC results showed up to a 30% reduction in calcium oxychloride (CaOXY) formation potential; however, this reduction may not be sufficient to avoid the potential damage associated with expansive CaOXY formation at concrete joints in pavements and flatwork. The NS admixtures did not affect chloride ingress profiles significantly. Thermodynamic calculations indicate that although the admixtures provide reactive silica that acts pozzolanically, the amount is relatively small compared to the admixture dosages used.
The damage rating index (DRI) is a microscopy tool that captures the extent of internal swelling reaction-induced deterioration (ISR). Although engineering practitioners more widely use mechanical tests, confirming the presence of ISR products through microscopy is required and standard practice. A more detailed evaluation can be achieved by combining mechanical and microscopy techniques, including the DRI, which has proven reliable in diagnosing the extent of ISR-induced deterioration. However, there is currently a lack of practical guidelines and standards in the literature explaining how to perform the DRI, raising concerns about the tool's use, particularly regarding operator variability and subjectivity. This work aims to create practical guidelines for conducting the DRI analysis methodology on concrete affected by alkali-silica reaction (ASR) originating from either reactive coarse or fine aggregates at various degrees of damage (i.e., 0.05%, 0.12%, 0.20%, and 0.30% expansion). Ranges of expected values were established to serve as autonomous training for new operators using the same reactive aggregates and mixtures.
Calcium sulfoaluminate (CSA)-based cements represent a promising alternative to traditional Portland cement, offering benefits such as rapid strength development, low shrinkage, and reduced carbon footprint. Despite their commercial availability and proven performance, the adoption of CSA cements remains hindered by gaps in standardization and understanding. This RILEM Technical Committee (TC) CSA aims to review current knowledge, identify research needs, and address challenges related to clinkering, hydration mechanisms, durability, applications, nomenclature, standardization, and testing of CSA-based cements. The outcomes will further the understanding of manufacturing, technical performance, use, and specification of CSA-based cements, ultimately leading to broader acceptance in concrete construction.
The RILEM technical committee on Performance-based Asphalt Recycling TC 308-PAR focuses on research, knowledge exchange and dissemination on the asphalt material recycling. Specifically, the Task Group 1 (TG1) “Performance-based Evaluation of Cold Recycled Asphalt Mixtures” aims at matching laboratory testing methods with the in-service behavior of cold recycled asphalt mixtures. In this context, the TG1 members collaborated to share the different cold recycling procedures used in their respective countries, with the goal of comparing specific practices, technical requirements, and performance expectations. Considering the different areas of expertise and application environments, such as road type, traffic volume, climate and material resources, the information gathered provides a broad framework of the current practices and prospects a widening of future application of cold recycling techniques. The comparison among country practices was divide into two papers: Part I dealing with constituent materials and common mixture composition and requirements and Part II treating testing procedures and mechanical characteristics. Particularly, Part I reports a critical comparison between standard frameworks for reclaimed asphalt (RA), cold recycling practices, materials and mixtures used in Italy, Canada, Poland, Brazil and USA, either adopted by selected road administrations or established by reference standards.
The durability of wastewater treatment plants has been a major concern for decades due to their significant economic and health importance. Structures built with concrete are subject to severe deterioration linked to aggressive chemical and biological exposure conditions. Portland cement concrete is particularly vulnerable to such attacks leading to major damages in the structures. One of the strategies to protect this concrete from the effects of biodeterioration is applying a thin coating based on calcium aluminate cement. These materials were proved to have a superior resistance to biodeterioration compared to ordinary Portland cement. However, the cracks initiated in the protected structure that might reach the coating raise questions on its ability to fulfill its protective role. This paper aims to study the effect of the crack on the durability of the coating using a biological laboratory test, the BAC test, which simulates the real conditions encountered in a sewer system. The calcium leached from the specimens exposed to the biogenic sulfuric acid attack was monitored in two campaigns of the BAC test. Each campaign was performed on reference OPC-based uncoated specimens and coated specimens with the CAC-based coating: uncracked and cracked with two ranges of crack width between 150 and 200 µm and between 400 and 500 µm. The leaching results demonstrate that the protective function was not altered by the effect of the cracks when comparing the reference uncoated specimen to the coated ones. The SEM-EDS observations show the existence of a newly-formed phase in the few hundreds of micrometers from the exposed surface of the coated specimens. This phase was composed mainly of calcium, sulfur and aluminum and was probably a mix of AH3 and ettringite. The formation of this phase near and inside the crack opening could possibly act as a physical barrier that prevents further deterioration.
Young’s modulus is commonly estimated using dynamic tests or from load and deformation measurements under static loading. However, these methods may yield different results due to variations in strain levels where characterisation is conducted. Existing studies reported discrepancies between static and dynamic Young’s moduli of hydraulic lime mortar. This paper examines the role that strain amplitudes and testing configurations play during Young’s moduli characterisation of prismatic samples to understand the root causes for these differences. Dynamic characterisation is conducted using standard impulse excitation of vibration tests while static characterisation is done with three-point bending and uniaxial compression tests. A tailored loading regime is used to examine the evolution of Young’s modulus at different strain levels. Repeated IEV measurements reveal progressive decay with increasing strain amplitudes. A similar trend is observed for static moduli, although decay magnitudes are notably higher and depend on the adopted test configuration. Reductions in Young’s moduli are associated with microscale damage processes and were observed at strain levels as low as 100 με. They become notably pronounced at compressive loads corresponding to ~30% of material compressive strength, which is typically used for static elasticity characterisation. The results highlight the small-strain nonlinearity of hydraulic lime mortar and indicate the need for improved characterisation procedures to describe the constitutive behaviour of this material.
To meet growing demands of stakeholders of the construction materials research field, new practices and methods must be established in handling metadata and raw data. Modelling approaches, simulation calculations and a targeted use of machine learning can save time and resources and is increasingly used in the industry as a decision-making tool. These techniques will play a crucial role in achieving the Net-Zero CO2 deadline of 2050. However, a better collaborative effort is required to ensure that data can be successfully reused. The task is challenging, as methods and strategies for data collection in the field of construction materials are diverse. The RILEM TC SDM (Scientific Metadata Management of Construction materials) aims to lay the foundation for a formal approach to metadata collection and management. As an initial step, a metadata collection framework and the associated input tool will be designed. Along with a best-practice guideline for the storage of raw data, this will help data producers establish a robust routine that aligns with the FAIR data principles, facilitating the data's reuse. The TC will provide the bridging element – the metadata file – that links the journal publication to the raw data. The metadata file can be easily stored and searched.
With over 8% of global carbon emissions worldwide, the cement industry is challenged to lower its carbon footprint. Replacement of clinker in cementitious systems becomes crucial. Sound research proved that kaolinitic clays with as low as 40% kaolinite can have a high reactivity as SCM. Further research studies found a synergy between the aluminates in calcined clays and the carbonates in limestone that led to the proposal of a ternary binder called Limestone Calcined Clay Cement, LC3, consisting of 50% Portland Cement, 30% calcined clay and 15% limestone. This paper presents the efforts of a group of members from 41 universities and 17 industrial partners through the RILEM Technical Committee 282 – CCL: Calcined Clays as Supplementary Cementitious Materials. The work was oriented to fill existing information gaps on characteristics of clay minerals, the process of clay calcination, hydration of cementitious systems containing calcined clay and limestone, fresh and hardened properties of concrete, standardization, and durability of concrete produced with binders containing calcined clay and limestone. The TC 282-CCL has published 10 whitepapers, with a strong contribution to a better knowledge and understanding of the role of calcined clay in cement and concrete.
Magneto-rheology control, an advanced active rheology control (ARC) technique, is achieved by applying an external magnetic field to a cementitious mixture with responsive additives. It is a promising method to address the contradicting rheological requirements of cementitious materials during the placing process, enabling the development of smart and reliable concrete structures. This article reviews recent advances in magneto-rheology control for cementitious materials. The fundamental principles of magnetic particle movement and cluster formation in cementitious suspensions are first examined. Afterwards, the typical magneto-rheological responses and the key factors influencing the responsive behaviors are discussed. Finally, the potential applications and challenges of this technology in modern construction practices, including smart casting process, 3D/4D concrete printing, and the development of sustainable and multifunctional concrete, are provided.
The cement and concrete industries are currently facing the urgent and arduous challenge of decarbonisation and material circularisation for improved resource efficiency. The pursuit of new raw materials and binders that will improve sustainability is urgent, especially as end-of-pipe carbon capture and storage (CCS) technologies have not yet been scaled up economically even after five decades of research and large investments. On the other hand, society is facing the colossal issue of managing mineral wastes which are produced in several Gts per year globally, posing a massive environmental and societal liability. Many of these mineral wastes have elemental and mineralogical profiles that make them good candidates for use as clinker raw feed or supplementary cementitious materials. Although the published research on the topic is extensive, it is not organised, lacking a systematic comprehensive approach, making valorisation challenging. RILEM TC UMW was developed to address this gap and create a framework for realising the potential of upcycling mineral wastes focusing on using powders as either clinker raw feed or other binder applications while excluding discussion on calcined clays and mineral carbonation.
The RILEM Technical Committee (TC) 281-CCC, on carbonation of concrete with supplementary cementitious materials (SCMs) was active from 2018 to 2024, bringing together over 120 members from different continents. The objective of the TC was to understand the mechanisms leading to carbonation and identify best practices for the assessment of carbonation resistance of blended cement concrete. The activities of the committee were carried out in five different working groups (WGs) centring on (i) effect of SCMs on natural and accelerated carbonation of blended cementitious materials, (ii) modelling of carbonation, (iii) effects of the combined action of load and carbonation, (iv) carbonation induced corrosion, and (v) carbonation of alkali-activated materials. These topics covered all critical aspects to reveal the connections between the mechanisms and factors leading to carbonation of binders and concrete with SCMs, the impact of carbonation in concrete performance and corrosion, and the suitability of existing testing methodologies for its evaluation. The scientific activities of the TC members led to the publication of a topical collection with nine articles in Materials and Structures and one article in RILEM Technical Letters. This included three critical review papers, six original research papers and one recommendation. In this Letter we provide an overview of the key findings linked to the WGs activities and present remaining research needs on the topic of carbonation of concrete with SCMs.
This technical letter investigates mechanical wave propagation (MWP) methods to characterize the stiffness of bituminous mixtures (BM), particularly using ultrasonic testing (UT) and impact resonance testing (IRT), as innovative alternatives to traditional quasi-static techniques. Recognizing the complexity of BM’s viscoelastic behavior influenced by temperature and frequency, the paper presents critical scientific and technological challenges to the newly started RILEM Technical Committee on MWP to characterize BM. By addressing the need for standardized testing procedures and data interpretation guidelines, the anticipated impact includes enhanced quality control and characterization capabilities that promote cost-effective pavement design. Furthermore, with this first effort on laboratory procedures, it is expected to facilitate future integration of non-destructive assessment methods into field practices, thus advancing the state-of-the-art in pavement engineering. This work aims to provide a robust framework for future research and practical applications in the characterization of bituminous materials.
For more than a century, the corrosion of steel in concrete has prevailed as a complex and yet poorly understood phenomenon, with many durability design approaches relying on phenomenological or semi-empirical service life models. The increasing societal demand to maintain aging infrastructure, the development of new cementitious binders and the push towards an environmentally more benign and circular concrete economy exacerbate the need for a more comprehensive scientific understanding of the underlying physicochemical processes, particularly in the absence of long-term empirical data. This manuscript retraces the history of thermodynamic modeling in cement and concrete research, examining early concepts, the barriers to adoption, and the pivotal role of modern Gibbs free energy minimisation solvers towards its broad level of acceptance within the scientific community. We further examine the current use of thermodynamic modeling techniques in corrosion science, emphasizing the limitations of classical potential-pH stability diagrams and addressing the widespread misconception that thermodynamics and kinetics are opposing concepts. Finally, we explore the opportunity to leverage the recent developments in the field of cement science and adopt thermodynamic modeling techniques in corrosion research, thereby addressing open questions related to the corrosion of steel in concrete.
