Masonry Construction Research Articles

Influence of Confining Element Stiffness on the In-Plane Seismic Performance of Confined Masonry Walls.

Confined masonry (CM) construction is being increasingly adopted for its cost-effectiveness and simplicity, particularly in seismic zones. Despite its known benefits, limited research exists on how the stiffness of confining elements influences the in-plane behavior of CM. This study conducted a comprehensive parametric analysis using experimentally validated numerical models of single-wythe, squat CM wall panels under quasi-static reverse cyclic loading. Various cross-sections and reinforcement ratios were examined to assess the impact of the confining element stiffness on the deformation response, the cracking mechanism, and the hysteretic behavior. The key findings included the observation of symmetrical hysteresis in experimental CM panels under cyclic loading, with a peak lateral strength of 114.3 kN and 108.5 kN in push-and-pull load cycles against 1.7% and 1.3% drift indexes, respectively. A finite element (FE) model was developed based on a simplified micro-modeling approach, demonstrating a maximum discrepancy of 2.6% in the peak lateral load strength and 5.4% in the initial stiffness compared to the experimental results. The parametric study revealed significant improvements in the initial stiffness and seismic strength with increased depth and reinforcement in the confining elements. For instance, a 35% increase in the lateral strength was observed when the depth of the confining columns was augmented from 150 mm to 300 mm. Similarly, increasing the steel reinforcement percentage from 0.17% to 0.78% resulted in a 16.5% enhancement in the seismic strength. These findings highlight the critical role of the stiffness of confining elements in enhancing the seismic performance of CM walls. This study provides valuable design insights for optimizing CM construction in seismic-prone areas, particularly regarding the effects of confining element dimensions and reinforcement ratios on the structural resilience.

Characterization and utilization capabilities of industrial wastes for green bricks production

BackgroundThe goal of this study is to develop a feasible and sustainable solution to manage the use of industrial wastes of ground granulated blast-furnace steel slag (GGBS) activated by cement kiln dust (CKD) and quicklime (QL). Using activated GGBS in the manufacture of stabilized green bricks is still uncommon in Egypt in such applications. Five clay-based mixtures, each with varying replacement ratios (5–10, wt.%) of CKD and QL, were studied. Laboratory tests were conducted on cylindrical specimens made from these mixtures, which were left to cure for periods of up to 60 days. The raw materials and lab-made specimens were analyzed using particle size analysis, differential thermal analysis, X-ray fluorescence, and X-ray diffraction techniques. The physical and mechanical properties of the cured specimens were also determined and evaluated according to standard specifications. Furthermore, the durability of the cured specimens was evaluated against collapsibility in water.ResuItsIt has been observed that adding QL and CKD to the stabilized green specimens of different mixes can enhance their engineering properties with curing age increasing. This is due to the pozzolanic reaction, which fills the pore structure with calcium silicate hydrates and calcium aluminate hydrates gel. The ratio of QL and CKD used significantly affected the engineering properties of the specimens. The study found that using 20% GGBS and 5% QL led to an increase in compressive strength (266 kg/cm2) at the density of (2.15 g/cm3), while also water absorption was reduced (8%) to give superior results. When GGBS and CKD were combined, a higher content of CKD (10 wt.%) gave better results compared to (5 wt.%) CKD. Furthermore, the physical and mechanical properties of the tested specimens (MD 1, MD II, MD III and MD IV) met the acceptable limits of dry compressive strength (30–70 kg/cm2), water absorption (8–15%), and density (1.7–2 gm/cm3), as specified by the Egyptian standard specifications for buildings used compressed earth blocks.ConclusionThe CKD and QL act as alkali activators for GGBS and can be utilized in masonry construction.

Porous interlocking assembly: performance-based dry masonry construction with digital stereotomy

Architected porosity in masonry structures can be created by transforming stock materials into a lattice of interlocking units through an automated batch process. Porous masonry forms numerous enclosed cavities for thermal performance and reduces material usage while maintaining structural integrity. This work investigates the potential and limits of digital tectonics of porous masonry through a complete process of design, manufacturing, and construction. The confluence of digital fabrication with tectonic exploration opens new dimensions unattainable by traditional stereotomy. Interlocking materials inspired by Abeille vault and digital stereotomy have made rapid progress. Following the theory of poetic construction, this work proposes that masonry construction should evoke visual or haptic enhancement through the fulfillment of pragmatic functions. We formulated a design challenge for a confined dry masonry wall for the envelope of the 2226 building. It assumes batch-cutting bespoke units out of large blocks of high-strength foam. Through a process of cutting and reassembling, the stock material is topologically expanded into a porous structure. A series of prototypes were developed to explore novel articulation, structural and thermal performance, and economical manufacturing. One can perceive the logic of porous construction through visual and haptic empathy. The materialization process interacts with the design masonry units and the interlocking mechanism. For future practice in masonry, the porosity should be planned at multiple scales (molecular scale, aggerate scale, construction scale) across the life cycle of the material.

Seismic Fragility Analysis of Existing Old Newari Brick Masonry Building in Pokhara Valley

Most of the building stock in Nepal is based on masonry construction, which includes monumental, administrative, and residential structures. These structures are vulnerable during earthquakes, as evidenced by the massive structural damage, loss of human life, and property damage due to a lack of proper assessment and appropriate strengthening measures. An analysis of the seismic vulnerability of existing old Newari brick masonry buildings in the Pokhara Valley is presented. These buildings were built using indigenous knowledge and technology. The investigation is based on analytical studies, with some material properties obtained from field tests. Proper modeling of a masonry structure is crucial for reliable seismic resistance and structural design. However, modeling a real masonry structure is a challenging and computationally demanding task due to its complicated framework, requiring in-depth knowledge, realistic material properties, and relevant information. The aim of this research is to assess the seismic performance of old Newari masonry buildings using stress level and fragility curves. The research issues are addressed analytically through linear time history analysis using the finite element program-based software Sap 2000 v20. In dynamic analysis, numerical building models were subjected to three synthetic earthquakes. The performance status of the building based on various stress levels is evaluated, and weak regions are identified. The fragility curve of the structure is assessed, considering the ground motion parameters in the locality. The fragility function is plotted with the probability of failure at an interval of 0.10 g. The results of the analysis highlight that the studied structure is vulnerable compared to the codal provisions and standard recommendations.

Dynamic behavior of axially loaded masonry walls strengthened with different innovative techniques under explosion loading

In the realm of construction engineering, brick masonry stands out as a pivotal structural element, renowned for its widespread application. Given the load-bearing nature of masonry structures, the ramifications of wall failure under extreme loads induced by explosions are profound. Particularly concerning is the out-of-plane failure of walls, which occurs without warning and affords scant time for assessment of their response. Brick masonry, characterized by its brittleness and susceptibility to cracking, presents inherent challenges in this regard. Recent examples, such as the Beirut explosion in 2020 and the Nashville bombing in 2020, vividly illustrate the devastating consequences of inadequate blast resistance in masonry structures. These incidents serve as poignant reminders of the imperative to fortify masonry constructions against explosive threats. While ample research exists on the behavior of free-standing braced and unbraced masonry walls subjected to explosive loading, there remains a notable gap in understanding the response of strengthened masonry walls exposed to blast loading, especially when carrying varying axial loads. This study addresses this gap by investigating different strengthening methodologies, namely (1) Cement-mortar plaster, (2) Ferro-cement, and (3) Carbon Fiber-Reinforced Polymer (CFRP) laminate, aimed at enhancing the anti-blast performance of unreinforced masonry walls. The experimentation focuses on a specific unreinforced masonry wall measuring 5000 × 2800 × 230 mm3, constructed from clay bricks and subjected to axial compressive loads of 51, 30, and 9kN/m, corresponding to the loads on the 1st, 2nd, and 3rd storey walls of a 3-storey masonry building, respectively. Utilizing a sophisticated finite-elements code, Abaqus, equipped with an explicit module and Concrete Damage Plasticity model, the blast simulations are meticulously conducted. The walls are meticulously modeled through detailed micro-modeling techniques. Results showed that the utilization of CFRP on the explosion-facing surface of the wall resulted in a remarkable reduction in damage, with the highest decrease of 64% achieved under the lowest axial compression. Conversely, the minimum decrease of 61.71% was recorded under maximum axial compression, highlighting the efficacy of CFRP in mitigating damage caused by explosions on walls. This research sheds light on effective methods to enhance the blast resistance of masonry walls, offering valuable insights for improving structural resilience and informing building codes. Its findings are crucial for ensuring the safety and security of infrastructure against explosive threats, ultimately safeguarding lives and property.

EVALUATION OF EARLY-AGE COMPRESSIVE STRENGTH OF GEOPOLYMER CONCRETE MASONRY UNITS

This paper presents the results of the experimental study on the early-age (1-day) compressive strength of geopolymer concrete masonry units (GCMU). The binder was a combination of ground granulated blast furnace slag (or simply slag) and fly ash with ratios of 3:1 and 1:1. It was activated using an alkaline solution consisting of sodium silicate and sodium hydroxide at a mass ratio of 1.5. Additional water was added to selected mixes to enhance the castability and compactability. The effect of the mix design parameters on the early-age compressive strength of GCMU was investigated. Results showed that an increase in the binder-to-aggregate ratio increased the compressive strength by up to 57%. Similarly, increasing the alkaline solution-to-binder and slag-to-fly ash ratios led to 4 and 3.5 times higher compressive strengths, respectively. Meanwhile, additional water had a negative impact on the compressive strength of GCMU, decreasing it by up to 74%. Still, it was possible to obtain a 1-day compressive strength of 36 MPa for a GCMU having a binder-to-aggregate ratio of 1:5, slag-to-fly ash ratio of 3:1, and solution-to-binder ratio of 0.4. Such results provide evidence of the ability to utilize geopolymer concrete in the field of masonry construction.

EVALUATION OF EARLY-AGE COMPRESSIVE STRENGTH OF GEOPOLYMER CONCRETE MASONRY UNITS

This paper presents the results of the experimental study on the early-age (1-day) compressive strength of geopolymer concrete masonry units (GCMU). The binder was a combination of ground granulated blast furnace slag (or simply slag) and fly ash with ratios of 3:1 and 1:1. It was activated using an alkaline solution consisting of sodium silicate and sodium hydroxide at a mass ratio of 1.5. Additional water was added to selected mixes to enhance the castability and compactability. The effect of the mix design parameters on the early-age compressive strength of GCMU was investigated. Results showed that an increase in the binder-to-aggregate ratio increased the compressive strength by up to 57%. Similarly, increasing the alkaline solution-to-binder and slag-to-fly ash ratios led to 4 and 3.5 times higher compressive strengths, respectively. Meanwhile, additional water had a negative impact on the compressive strength of GCMU, decreasing it by up to 74%. Still, it was possible to obtain a 1-day compressive strength of 36 MPa for a GCMU having a binder-to-aggregate ratio of 1:5, slag-to-fly ash ratio of 3:1, and solution-to-binder ratio of 0.4. Such results provide evidence of the ability to utilize geopolymer concrete in the field of masonry construction.

An integrated digital design and construction approach for falsework-minimal masonry vaults

Masonry vaults, mechanically efficient structures, are challenging to build because they require significant tailored falsework as temporary structures for centering, guidework, and scaffolding, which decreases construction productivity and increases financial cost and environmental impact. Traditional building techniques combined with recent digital technologies can eliminate such temporary construction. An integrated digital design and construction approach that leverages the benefits of four construction strategies (namely, thin-tile vaulting, loxodrome tessellation, augmented reality, and prefabricated spine) within a 4D funicular design framework is presented in this paper and illustrated by a large-scale demonstrator, innixAR. This structure demonstrates that the combination of the vernacular craft of thin-tile vaulting with augmented reality technology to produce a digital guidework, informing a 4D funicular design process that considers the entire construction sequence from a prefabricated spine, minimizes the required falsework, making the construction of masonry vaults more efficient and affordable. This approach is benchmarked against alternative conventional vault falsework. Combining thin-tile vaulting and prefabricated spine allowed a reduction of 82% of the falsework mass, making transport lighter. Whereas combining digital guidework and prefabricated spine allowed a reduction of 91% of the falsework elements, making assembly faster. This research contributes to the development of structures that are efficient both mechanically and constructionally.

Investigating and monitoring central nave vaults of the Turin Cathedral with Acoustic Emissions and Thrust Network Analysis

Ancient masonry constructions and historical buildings, such as cathedrals, are exposed to considerable risks attributed to factors like ageing and long-term exposure to both dynamic and static variations in loading conditions. In this study, an innovative and promising monitoring approach was applied to assess the structural integrity of the vault in the central nave of the Turin Cathedral. Specifically, the outcomes obtained from Acoustic Emissions (AE) are correlated with the insights derived from the Thrust Network Analysis (TNA) conducted on the structure. This analysis considers the structural elements introduced early in the twentieth century to mitigate horizontal forces. Acoustic Emission (AE) is a commonly employed technique in structural monitoring to detect and analyze elastic waves generated by crack formation, providing valuable information about structural damage. The Thrust Network Analysis (TNA) is an approach that applies Heyman's principles to represent stress in masonry vaults. This method models the stresses as a discrete network of forces, achieving equilibrium with gravitational loads. In this context, the results obtained by TNA analysis are strictly correlated with AE localization results.

Mechanical and Durability Investigation of Composite Mortar with Carbon Microfibers (CMF)

This paper investigates the mechanical properties and the durability implications of innovative cement-based mortars doped with carbon microfibers. In particular, mixes with different amounts of carbon additions are produced, and the properties of fresh and hardened samples are analyzed through workability, water absorption, and compressive and flexural tests under specific environmental conditions. These composites can be employed to enhance construction performance or provide structures with strain-monitoring capabilities. However, the analysis of their mechanical properties and their durability behavior is needed before extensive structural use. In this work, the preparation procedure is defined for the various mix designs, considering different amounts of carbon microfibers; then, fresh properties are evaluated, and different types of samples formed. After various curing times, the specific rheological and hardened properties of the specimens are tested in different conditions to consider the durability of the composites, essential for the real-scale adoption in structural elements. Preliminary electrical and sensing tests are first conducted to evaluate the monitoring potential of the investigated composites. The findings highlight the impact of carbon inclusions on the performance of cement-based mortars, offering valuable insights for their utilization in masonry construction or for repairing concrete structures. In particular, sensing capabilities are found to be highly enhanced by the presence of CMF. Additionally, the results of this research pinpoint key areas for further analysis in the material’s development process.

Aspects Affecting the Quality of Masonry Buildings and Innovations in Masonry

The construction industry is undergoing another revolution, including the field of masonry construction. New materials and products for masonry are constantly being developed and construction details and implementation procedures are being resolved. Digitization and the introduction of automation in the masonry process (in prefabrication halls or on-site robotic bricklaying) are also an integral part of the development of the masonry construction industry. The topic of the following paper is a summary of problematic construction details of masonry buildings, i.e., the solution of the plinth console, the solution of the building opening, the bearing of lintels on the masonry and the bearing of the ceiling structure on the masonry wall. The results of laboratory tests are presented – the load-bearing capacity of the jamb of the building opening (accessory bricks / cut bricks in the jamb) and the load-bearing capacity of the lintel placed on the accessory edge brick. Furthermore, the paper deals with the construction of masonry buildings in the 21st century, including the first results of a compressive load test on masonry walls made of precast small-format units. The conclusion of the paper points out the importance of correct design details of masonry buildings before their application (programming) in software controlling the automated masonry process.

External Wall Systems in Passive House Standard: Material, Thermal and Environmental LCA Analysis

The construction sector, a significant consumer of energy, possesses the potential to realize substantial environmental and economic advantages through the adoption of innovative technologies and design approaches. Notably, the Passive House standard, exemplified by energy-efficient single-family homes, emerges as a prominent solution. This study analyzes five external wall systems across multiple stages: (i) a literature review and examination of external wall techniques within the passive standard, utilizing the Passive House Database; (ii) a material and technological assessment of three wood-based and two masonry constructions; (iii) an in-depth thermal performance analysis of selected external partitions; and (iv) a Life Cycle Assessment (LCA) of the external wall systems. Our findings indicate that among the single-family homes built to the passive standard, 50.94% utilized timber constructions, while 34.21% employed masonry. Thermal analysis revealed that the masonry wall, EW-M-01, exhibited superior thermal efficiency with a heat transfer coefficient (U-value) of 0.0889 W/m2K. Meanwhile, the wooden wall, EW-T-01, led its category with a U-value of 0.1000 W/m2K. The LCA highlighted that the wooden wall EW-T-02 presented the lowest integrated non-renewable energy demand (PENTR) at 425.70 MJ/kg and the most favorable Global Warming Potential (GWP), with a reduction of 55.51 kg CO2e. Conversely, the masonry wall EW-M-01 recorded the highest energy demand and CO2e emissions, at 780.96 MJ/kg and 90.59 kg CO2e, respectively. Water consumption was lowest for the EW-T-02 wooden wall (0.08 m3) and highest for the EW-M-02 masonry wall (0.19 m3). Conclusively, our analysis of passive house external walls demonstrates that wood-based systems offer superior performance in terms of materials, thermal efficiency, and LCA indicators, positioning them as the preferred option for sustainable passive construction.

Valorization of Cappadocia waste earth in the production of sustainable lime-based grouts

Historical structures and natural landscapes in Turkey's Cappadocia Region, a popular tourist spot, have been designated mixed heritage sites on the World Heritage List since 1985. The region's old rock-cut and masonry constructions have been damaged for various reasons. Furthermore, the waste volcanic tuff excavated during the construction of rock-cut structures in the region totals around 10 million tons of waste material per year. It creates severe visual concerns since it cannot be used effectively in the area. Because repairing ancient buildings needs precision, the restoration method and material should be selected based on the structures' structural system and material attributes. Grouting is one of the most common ways of repairing and strengthening masonry buildings or fissured architectural pieces with adequate connected voids. This technique aims to restore damaged structures' continuity, cohesiveness, and strength while keeping their morphology and load-bearing system intact. This research explores the potential use of waste earth from rock-cut structures in the Cappadocia Region in hydraulic lime-based grouts. Thus, an injection material that can be used to repair fairy chimneys and historical rock-cut and masonry structures in this region will be produced. Various lime-based grout types containing Cappadocia waste earth (CWE) were produced in this scope. The evaluation of grout performance encompassed assessments in the fresh state (Fluidity, Penetrability, and Volume Stability) and the hardened state (Flexural and Compressive strength). Furthermore, this research delved into how Cappadocia waste earth (CWE) influences the physical and microstructural characteristics of lime-based grouts. Thanks to this study, both environmental pollution will be reduced, and sustainability will be contributed.

Investigating the damage to masonry buildings during shield tunneling: A case study in Hohhot Metro

After prolonged service, masonry buildings constructed in the 1970s and 1980s often experienced significant deterioration in strength and stiffness. Excessive ground deformation caused by shield tunneling frequently leads to cracking in adjacent masonry buildings. Most studies have focused on the settlement and tilting caused by shield tunneling on masonry structures, failing to reflect the specific damages caused by shield tunneling. This paper employs a jointed masonry model in numerical simulations to simulate masonry buildings, considering the actual measurement data from the Hohhot Metro Line 1 project. It discusses a thorough investigation into the potential damages and cracking on masonry buildings that may occur during shield tunneling in masonry structures. It provides a detailed study of the specific forms of cracking in masonry buildings. Then, a comprehensive and in-depth analysis is conducted on the impact of bricklaying methods, mortar adhesive strength, and synchronous grouting pressure on buildings in the context of shield tunneling through structures. The results show that using the jointed masonry model can effectively reflect the cracking and damage situation of masonry structures during shield tunneling construction, providing valuable guidance for actual shield tunneling operations. The area of cracking damage caused by shield tunneling construction gradually increases from the top to the bottom of the building. It is concentrated above the doors and windows of the structure. Potential cracks around door and window openings extend from the upper-middle part of the openings towards both sides, forming a regular figure-eight distribution. With changes in the masonry construction method, grouting pressure, and mortar bond strength, the settlement and damage levels of the building also undergo alterations. Specifically, as the mortar bond strength increases from 30 kPa to 50 kPa, the maximum tensile strain of the masonry construction decreases to 0.11 %. Simultaneously, when the construction method of the building bricks transitions from A to B, the damage at the door and window openings on the west wall of the building gradually intensifies, resulting in a rise in the maximum tensile strain to 0.109 %. Furthermore, as the grouting pressure increases from 50 kPa to 300 kPa, the maximum settlement of the building walls decreases by 51 %, and the maximum tilt reduces by 48 %. However, this study did not account for the lintels and sills in the masonry building, which may lead to an overestimation of simulated strain data.

Study on the Mechanical Properties of Two General-Purpose Cement-Lime Mortars Prepared Based on Air Lime.

It is believed that the use of mortars based on air lime in the construction and renovation of brick buildings has a number of advantages, especially those closely related to the durability and strength of the structure. However, there is still a noticeable difference in the mechanical properties of these materials. This research investigated the mechanical characteristics of a mixed cement-lime mortar with the two most popular proportions of an air lime, cement, and sand mix: 1:1:6 and 1:2:9 (by volume). Mechanical tests were performed on standard and non-standard samples to assess compressive strength, tensile strength, flexural strength, and fracture energy. The obtained results indicate the possibility of using these mixtures in modern masonry construction, as well as in the aspect of sustainable development. Additionally, lime mortar with a higher lime content can be used in non-load-bearing walls and in renovation and repair works.

The use of containers as a constructive method in buildings: a viable and sustainable alternative

With the increase in environmental concern, alternatives for the use of resources that are less harmful to the environment have been explored, including materials and construction methods. In this context, there is a growing search for new construction processes, especially container buildings, which have gained popularity and acceptance in society, being applied in both commercial and residential contexts. The main attractions for those interested in acquiring a container construction are the reduction of costs and the shortening of the execution time of the work. This is due to the minimization of waste generated during construction and the recycling of metal boxes, which would otherwise remain useless in ports. This advantage goes beyond the economic benefits, contributing to adding sustainable value to the project. This paper aims to discuss the feasibility analysis of the use of containers as a sustainable and financially advantageous proposal compared to conventional methods of structural construction for housing. Through a literature review, evidence of the feasibility and reuse of shipping containers for housing purposes is presented, exploring viable alternatives for the use of waste. The comparative study is based on the parameters established by the National System of Research on Costs and Indices of Civil Construction – SINAPI. The steps include the initial survey of all the improvements and adaptations necessary to provide housing conditions, considering standards of acoustic comfort, lighting, and ventilation. The results indicate that the reuse of the container results in savings of approximately 10% compared to masonry construction. Therefore, this approach has numerous advantages, being a financially viable, fast, and flexible solution for new architectural arrangements, in addition to incorporating architectural innovations aligned with environmental awareness.

THE CATHEDRAL OF SAN MASSIMO IN FORCONA (AQ): ARCHAEOLOGICAL ANALYSIS AND INTEGRATED DIGITAL EXPERIENCES FOR VR EXPLORATION AND SITE ENHANCEMENT

Abstract. The contribution aims to present the results obtained from the archaeological analysis of the architecture of the Cathedral of San Massimo in Forcona (AQ), which took place in 2021, focusing on the digital systems used for the documentation and valorization of the monument. The work is part of a broader research project developed by the University of L'Aquila and focused on the archaeological study of medieval architecture as a function of the creation of a database on a chronological-typological basis of the masonry construction techniques of the city and its territory. The first structure to be analyzed was the Cathedral of San Massimo in Forcona, which, although it is located at a significant distance from the city center, represented a power pole of fundamental importance for the political-economic administration of the territory, at least until the construction of the city of L'Aquila. The documentation carried out through integrated TLS/SfM digital surveys and archaeological analysis allowed first to establish a chronological sequence of the construction phases of the church, but also to hypothesize through 3D reconstructions the historical evolution of the entire architectural complex. These reconstructions then became the digital support for the creation of a series of immersive VR systems aimed at providing experiences of interactive storytelling and dissemination of research outcomes.

Study on the shear properties of masonry pagoda mortar and its influencing factors

Mortar stands as one of the fundamental components in masonry construction, significantly enriching the global cultural heritage, particularly evident in ancient masonry structures. In this paper, the improvements of shear strength of mortar were studied, based on the original formulation material of sticky-rice lime mortar. The study considered the effect of different aggregates and additives on the shear strength of mortar, the shear tests and scanning electron microscopy were employed to analyze the shear strength index and microscopic shear basis of the mortar. The results showed that 2 wt% Na-SiO2 significantly enhanced the shear strength of the mortar. Furthermore, the adhesion and frictional resistance between fiber and lime played a crucial role in enhancing the mortar's shear resistance. Incorporating a 0.5 wt% fiber additive not only effectively improved the mortar's brittleness but also acted as a deterrent to crack formation. Compared to pure lime mortar, the mixture of sand and clay aggregate exhibited a larger capacity at the same volume. This mortar also showcased better plasticity and ductility, making it more suitable for structures with significant shear deformation. These analytical findings provide valuable insights for modifying mortars in the restoration of historical buildings.

Unreinforced concrete masonry for circular construction

This paper proposes an effective approach to realise circular construction with concrete, and shows Unreinforced Masonry as a foundational building block for it.The paper outlines the importance of circularity in building structures. It specifically focuses on the impact of circular construction with concrete on improving the sustainability of the built environment in a rapidly urbanising world economy. Subsequently, the relevance of principles of structural design and construction of unreinforced masonry to achieve circularity is articulated. Furthermore, the paper presents and summarises recent developments in the field of Unreinforced Concrete Masonry (URCM) including digital design tools to synthesise structurally efficient shapes, and low-waste digital fabrication techniques using lower-embodied-emission materials to realise the designed shapes. The paper exemplifies these using two physically realised, full-scale URCM footbridge prototypes and a commercially available, mass-customisable building floor element, called the Rippmann Floor System (RFS).The paper also outlines the benefits of mainstream, industrial-scale adoption of the design and construction technologies for URCM, including accelerating the pathway to decarbonise the concrete industry. In summary, the paper argues that URCM provides a solution to significantly mitigate the carbon emissions associated with concrete and reduce the use of virgin resources whilst retaining its benefits such as widespread and cheap availability, endurance, fire safety, low maintenance requirements and recyclability.

Improved Bond Stress-Slip Relationships for Carbon Fibre-Reinforced Polymer-Strengthened Masonry Triplets

Carbon fibre-reinforced polymer (CFRP) emerges as a viable solution for reinforcing unreinforced masonry (URM) walls subjected to shear loads. While masonry structures are straightforward to construct, the complexity of the construction materials, especially in terms of their mechanical properties, poses challenges for numerical studies of their structural behaviour. Walls, being fundamental components in masonry construction, play a crucial role in transferring both horizontal and vertical lateral forces. This study investigates the enhancement of masonry wall behaviour through the reinforcement of CFRP. CFRP reinforcement increases ductility and strength, reducing the risk of failure under shear conditions. Additionally, CFRP composites present a practical solution to strengthening masonry structures compared to traditional reinforcement. However, brick, mortar, and CFRP have not been thoroughly investigated. Experimental tests on the bond behaviour of different configurations of CFRP-retrofitted masonry triplets have not been performed before and are therefore presented in this paper. Triplet specimens, comprising three bricks and two mortar joints, both with and without CFRP strengthening, were subjected to bond testing. The study affirms that masonry triplets strengthened with CFRP under shear loads exhibit strength levels at least four to six times greater than those without CFRP. The experimental work was carried out with eight different CFRP configurations on triplet masonry, and each test was repeated four times. Further, the bond stress-slip relationship in the case of masonry triplets with and without CFRP was predicted with new mathematical equations based on the conducted test results. These equations were included in the commercial finite element software ANSYS and used to conduct simulations of CFRP-reinforced masonry triplets. The numerical results indicate good agreement between the finite element model and the test results. The outcome of this research improves the current knowledge on the use of CFRP to reinforce masonry walls with brick and mortar, which will contribute to the understanding of the effect of CFRP on masonry structures.