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This paper presents investigations on the tensile behavior of several textile-reinforced concrete (TRC) material compositions after fire exposure. First, experimental investigations are presented, aiming to provide insights into the thermomechanical performance of fire-exposed TRC, and data that can be used for the development and implementation of analytical or numerical models to design fire-exposed TRC elements. The applicability of the Aveston-Cooper-Kelly (ACK) theory is assessed for ambient and increased temperatures. TRC specimens with various cases of reinforcement (carbon or glass fibers, uncoated or coated textiles, low or high fiber volume fraction) were manufactured and subjected to temperatures reaching 700°C. The residual tensile capacity of the exposed specimens is discussed, focusing on the effect of the varying reinforcement. It is verified that the use of uncoated carbon fibers is the most promising solution for maintaining the residual capacity after fire exposure. Finally, it is concluded that the ACK predictions are reliable for TRC specimens with good bond conditions and when adopting a representative thermal degradation law for the reinforcement.

Textile-reinforced concrete (TRC) is a promising composite material with enormous potential in structural applications because it offers the possibility to construct slender, lightweight, and robust elements. However, despite the good heat resistance of the inorganic matrices and the well-established knowledge on the high-temperature performance of the commonly used fibrous reinforcements, their application in TRC elements with very small thicknesses makes their effectiveness against thermal loads questionable. This paper presents a state-of-the-art review on the thermomechanical behavior of TRC, focusing on its mechanical performance both during and after exposure to high temperatures. The available knowledge from experimental investigations where TRC has been tested in thermomechanical conditions as a standalone material is compiled, and the results are compared. This comparative study identifies the key parameters that determine the mechanical response of TRC to increased temperatures, being the surface treatment of the textiles and the combination of thermal and mechanical loads. It is concluded that the uncoated carbon fibers are the most promising solution for a fire-safe TRC application. However, the knowledge gaps are still large, mainly due to the inconsistency of the testing methods and the stochastic behavior of phenomena related to heat treatment (such as spalling).

Textile Reinforced Cementitious (TRC) composites can be used as an alternative to traditional load-bearing materials due to their high tuneability, slenderness and freedom-of-form. The modelling of TRCs is traditionally subdivided in discrete and smeared approaches. Discrete approaches model the reinforcement and matrix separately but require a bond characterization whereas smeared approaches distribute the mechanical properties evenly over the cross-section. The flexural behaviour of TRCs where the reinforcement is non-uniformly distributed over the height is strongly influenced by the position of the textiles and can therefore not be predicted by fully smeared simulations. Semi-smeared approaches solve these challenges by discretely stacking smeared layers with individual mechanical properties and compromise between discrete and smeared approaches. This research presents a detailed explanation of a semi-smeared, layered Finite Element (FE) model and validates it by experiments on TRC beams with non-uniform and non-balanced longitudinal and shear reinforcement layers. Two different layup alternatives were simulated. The simulations showed a good agreement with the experiments and highlighted the ability of the model to predict the pre- and post-cracking flexural stiffness. Furthermore, investigation of the simulated stress and strain distributions in the flexural shear zones highlighted the ability of semi-smeared models to endorse experimentally observed failure phenomena.

Driven by the need for alternative construction materials, recent developments have been steered towards the use of natural fiber reinforced cement composites. Ensete Ventricosum (Ev) offers a promising candidate as reinforcement in cement matrices but has not yet been studied in the literature. This research assessed the mechanical performance and durability of Ev fiber reinforced cement composites. Cracking behaviour was studied using the optical Digital Image Correlation (DIC) technique. The Ev fiber reinforced composites achieved a desirable post-cracking behaviour and the stiffness, toughness, and flexural strength increased with increasing fiber dosages. After 6 and 12 wet/dry cycles and 50 heat/rain cycles, all composites showed significant strength losses. This was attributed to the severe degradation of the Ev fibers and their low volume fraction.

Lightweight hybrid concrete beams are advantageous in terms of installation, but their mechanical behaviour is not easy to predict due to their heterogeneity. In the present study composite hollow beams made of Textile Reinforced Cement (TRC) reinforced with Carbon Fibre Reinforced Polymer (CFRP) strips and a concrete layer are subjected to bending. Their fracture behaviour is complicated as they exhibit multiple failure mechanisms: cracking of the cement matrix, debonding of the CFRP and delamination between successive layers of TRC. Herein, their mechanical performance is evaluated and monitored by Acoustic Emission (AE) and Digital Image Correlation (DIC). AE indices show that beams suffering from one major failure mechanism (matrix cracking) release AE signals with high frequency content while beams suffering from delaminations exhibit longer AE waveforms of lower frequency. These tendencies are obvious even at early loading stage, enabling prediction of the mode of the subsequent failure.

Textile Reinforced Cements (TRCs) offer an adequate alternative to more conventional building systems in construction due to their tunable and lightweight geometries. TRCs are currently either modelled by means of a discrete approach, where the textiles and the matrix are modelled separately, or by means of a smeared approach that averages the material's mechanical response over the cross-section. The research presented in this paper proposes a new, layered-wise approach of modelling where the through-thickness response of the composite is subdivided in different layers with individual mechanical properties. A tensile experimental campaign on different combinations of TRC layups, combining both glass and carbon fibre textiles, is performed and used as an input for the layered-wise numerical model. The model is then validated by comparison with flexural experiments performed on four different TRC layup combinations. The good agreement witnessed between the numerical predictions and the experimental results validates the layered-wise modelling approach proposed in this paper.

Internal interfacial debonding (IID) phenomena on sandwich fa&ccedil, ade insulated panels are detected and tracked by acoustic emission (AE). The panels are made of a thin and lightweight cementitious composite skin. In the lab, the panels are tested under incremental bending simulating service loads (i.e., wind). Local (up to 150 mm wide) skin-core detachments are reported in the early loading stage (at 5% of ultimate load) and are extensively investigated in this study, since IID can detrimentally affect the long-term durability of the structural element. A sudden rise in the AE hits rate and a shift in the wave features (i.e., absolute energy, amplitude, rise time) trends indicate the debonding onset. AE source localization, validated by digital image correlation (DIC) principal strains and out-of-plane full-field displacement mapping, proves that early debonding occurs instantly and leads to the onset of cracks in the cementitious skin. At higher load levels, cracking is accompanied by local debonding phenomena, as proven by RA value increases and average frequency drops, a result that extends the state-of-the-art in the fracture assessment of concrete structures (Rilem Technical Committee 212-ACD). Point (LVDT) and full-field (AE/DIC) measurements highlight the need for a continuous and full-field monitoring methodology in order to pinpoint the debonded zones, with the DIC technique accurately reporting surface phenomena while AE offers in-volume damage tracking.

This Special Issue presents the latest advances in the field of Textile-Reinforced Cement Composites, including Textile-Reinforced Concrete (TRC), Textile-Reinforced Mortar (TRM), Fabric-Reinforced Cementitious Matrix (FRCM), etc. These composite materials distinguish themselves from other fibre-reinforced concrete materials by their strain-hardening behaviour under tensile loading. This Special Issue is composed of 14 papers covering new insights in structural and material engineering. The papers include investigations on the level of the fibre reinforcement system as well as on the level of the composites, investigating their impact and fatigue behaviour, durability and fire behaviour. Both the strengthening of existing structures and the development of new structural systems such as lightweight sandwich systems are presented, and analysis and design methods are discussed. This Special Issue demonstrates the broadness and intensity of the ongoing advancements in the field of Textile-Reinforced Cement composites and the importance of several future research directions.

Using large lightweight insulating sandwich panels with cement composite faces offers great possibilities for the renovation of existing dwellings. To guarantee the structural performance of these lightweight panels, it is necessary to quantify the impact of varying weathering conditions in the long term. Therefore, this study investigates sandwich beams with textile reinforced cementitious composite faces subjected to heat-rain, heat-cold and/or freeze-thaw cycles to simulate the different weathering conditions. To separate the degradation effects at the sandwich element level from the degradation mechanism related to the face material level, also textile reinforced cementitious composite plates were subjected to identical environmental loading. The observations at the material level did not match the observations at the element level. While the structural performance of the textile reinforced cementitious composite plates was strongly affected by the durability cycles, the sandwich panels showed a non-degraded mechanical response after environmental loading.

In outdoor applications, textile reinforced cementitious composites (TRCs) are susceptible to varying weathering conditions. To guarantee their performance during the entire life-time, it is necessary to evaluate the long-term behaviour. In this paper, the mechanical behaviour of reference specimens is compared to aged specimens, which are subjected to heat-rain and/or freeze-thaw cycles. Results show that subjection to heat-rain cycles leads to a larger degradation of the tensile behaviour compared to subjection to freeze-thaw cycles. Besides the macroscopic tensile behaviour, also the cracking behaviour is evaluated. Analysis shows that cracks are formed at lower stress levels after being subjected to environmental loading.

Textile Reinforced Cement composites (TRCs) have become a key research topic when it comes to lightweight alternative construction materials for traditional concrete industry. While most of the research performed on TRCs combines a cementitious matrix material with 2D textile fabrics, this paper investigates the mechanical behaviour of TRCs reinforced with 3D textile fabrics. The main goal is to investigate the influence of the transversal fibre that is connecting the fibre layers and is typical for 3D textiles, on the tensile and flexural properties of the TRC. Therefore two textile fabric architectures were compared, firstly an unaltered 3D textile fabric and secondly a tensile-equivalent 2D textile fabrics with equal in-plane textile reinforcement. An experimental campaign in tension and bending was performed on four different TRC layups. When comparing the bending behaviour of the unaltered 3D-TRCs with the 2D alternatives, an increase in stiffness in the post-cracking stage was observed, while no influence was observed in tension. The experimental results were also compared with numerical predictions of the 2D-TRCs to put in evidence the influence of the 3D architecture.

Driven by the search towards new materials with reduced ecological impact, several investigations on plant-based natural fibers for composite reinforcement have been undertaken by researchers in the past decades. However, Ensete Ventricosum (Ev) fiber as reinforcement in a cementitious matrix has not yet been studied. This research aims to assess the mechanical performance of aligned Ev fiber reinforced cementitious composites and particularly the influence of the fiber volume fraction on the flexural performance of the composite. Four different fiber content ratios (from 3 % up to 6 %) were compared to plain mortar specimens. Not only the flexural load–displacement but also the cracking behavior was studied in depth utilizing the optical Digital Image Correlation (DIC) technique. The developed material presented multiple cracking behavior under bending. The post-cracking stiffness, toughness and flexural strength of Ev fiber reinforced specimens were increased with higher fiber content: 3 %, 4 % and 5 % fiber content resulted in a strength increase of 260 %, 274 % and 396 %, respectively, compared to that of the reference mortar specimen. These results are promising for the development of a Ev fiber-based green composite.

In the application of cement composites as Externally Bonded Reinforcement (EBR) for concrete structures, debonding is reported to be a common and undesired failure mode. This paper presents an indirect bond identification method that incorporates the nonlinear material behaviour of cement composites. The extended nonlinear indirect method is compared with a linear method by means of virtual and laboratory experiments. The virtual experiments allow omitting measurement scatter and hence quantify the error inherent to the theoretical assumptions. The laboratory experiments validate the use of the indirect method on real slip measurements. The results show that incorporating the cement composite’s nonlinear secant modulus as a function of the occurring strain is essential to accurately determine the cement composite – concrete bond from experiments.

The advantages of high performance composite materials have stimulated their use as reinforcement in concrete structures as well as the research on hybrid composite-concrete elements. For the design of these hybrid structures – with often complex geometries – the standard concrete calculation rules, based on official codes such as Eurocode 2, are often not elaborated enough. Moreover, these standard models are limited or simplified to a linear behaviour and do not even allow the integration of nonlinear reinforcement behaviour. In this paper, the authors propose a general calculation methodology to simulate analytically the structural behaviour of hybrid beams, including their ultimate loadbearing capacity and deflection. This methodology introduces an original search algorithm that reduces the computation time significantly without losing accuracy. The analytical model is validated by ten experiments on 3-m-span hybrid beams with differing geometry. The experiments demonstrate the accurate prediction of the analytical model both for the load–deflection behaviour and for the occurring strains, and confirm the model assumptions made. Moreover, the structural feasibility of the proposed hybrid beams is demonstrated as they exhibit a sufficient loadbearing capacity and stiffness. This structural performance in combination with the ability to predict the behaviour reveals a great potential for future structural applications.

This paper demonstrates the importance of including non-linearities in the design of textile reinforced concrete (TRC) shells. By two cases, the influence on the buckling load of considering geometrical non-linearity and material non-linearity, but also of considering geometrical imperfections is examined. For stiff shells mainly in compression, the buckling load is significantly reduced by including imperfections, analogue to observations with steel reinforced concrete shells. For shells with a low stiffness, experiencing large deformations, a non-linear analysis is essential and the buckling load is mainly reduced by considering material non-linearity. Conclusively, the shape and boundary conditions of thin TRC shells indicate which parameters should be taken into account in their design.

The fracture processes on coupons of glass-fibre textile reinforced cementitious (TRC) matrix composites under tension are revealed using acoustic emission monitoring (AE) method. The fundamental study, based on acoustic signals magnitude, shape and frequency content, discloses the presence of early mortar micro-cracking and assesses the nature of multi-scale damage developed as the ultimate matrix strength is reached. At post-cracking stage, the AE signals are classified to indicate different fracture mechanisms: fibres extension, textile slippage and matrix-fibres debonding. Digital image correlation is applied as supplementary technique to verify the AE outcome. For the first time in literature, the proposed AE-based methodology fully characterizes and provides an inside view of the fracture process on TRC coupons under tension overcoming modelling assumptions that were previously in place.

The use of Acoustic Emission (AE) as an indirect method to reveal the fracture behavior of textile reinforced cementitious composites (TRC) is discussed in this paper. AE is selected since limited information on TRC fracture can be obtained based their loading behavior. AE signal features analysis and source localization provide information regarding damage mode evolution: cement cracking onset, interfacial debonding, textile breakage and merging of aforementioned damage mechanisms. The study summarizes the main findings of recent research in the range from small preliminary laboratory coupons to more complex freeform TRC plates that simulate the performance of real TRC structures under service loads. Ultimately, the proposed AE methodology aims to be established as the most promising health assessment tool.

This work aims to study an aluminosilicate phosphate cementitious matrix. The cementitious matrix was studied on paste samples. The synthesis of metakaolinite phosphate cement (MKPC) was investigated using calorimetric techniques. A systematic study was performed by emphasizing a broad range of Al/P molar ratios, covering the different behavior of the material to the extremes, as well as the optimum composition. X-ray diffraction and scanning electron microscopy revealed that the final structure was mainly an amorphous network, albeit with some non-reacted phases. The compressive strength was studied on mortars using a cement/sand ratio of 1:3. MKPC specimens with Al/P ratios close to 1/1 showed optimal behavior. MKPCs with Al/P ratios above 1/1 were characterized by high porosity and low strength, whereas MKPCs with Al/P &lt, 1 contained an excess of phosphates. The influence of the Al/P molar ratio on compressive strength was also studied, reaching a maximum of 68 MPa for the optimum composition. Based on the results, MKPC may be a promising candidate for construction purposes.

Prefabricated building walls of the future will be thinner and lighter than ever. Fiber textile reinforced concrete walls can be built up few millimeters thick, decreasing this way the environmental impact of the structure. The innovative design is discussed in literature the recent decade under the scope of ‘textile reinforced cementitious composites (TRC)’. The TRC wall elements carry layers of orthogonal fiber mats that can withstand and eliminate tensile cracks on concrete cover. The design of TRCs is still under investigation. Indicatively, research is done to optimize the textile geometry, introduce three-dimensional fiber waving techniques, enhance the interfacial concrete-fibers bonding conditions. Simulating service-life loading conditions, our study aims to thoroughly assess the mechanical response of TRC elements in tension. Small scale TRC coupons are cured in freeze-thaw and heat-rain conditions and afterwards are tested in crack opening fracture mode (mode-I). The main damage mechanisms (i.e. concrete multiple cracking, interfacial debonding, textile deformation and fibers pull-out) are monitored using Acoustic Emission (AE) and other optical measuring techniques. Based on AE hits analysis, the damage mode is identified at different loading stages. Furthermore, AE hits features are examined and their trends reveal the presence of early matrix micro-cracking. The latter can be attributed to the effect of durability loads on TRCs response to fracture.

The combination of high performance composites and concrete results in hybrid composite-concrete elements which no longer resemble the traditional reinforced concrete structures. Consequently, these hybrid elements have a different structural behaviour that requires new evaluation procedures. This paper focusses on hybrid TRC-composite-concrete elements which are used as a substitute for reinforced concrete beams within a floor system. Their shear behaviour is experimentally investigated by the examination of ten short-span hybrid beams with different geometries. Visual inspection shows that shear failure occurs by an inclined flexural shear crack in the concrete. A rosette strain gauge analysis proves that the principal strain and stress orientations are in accordance with theoretical predictions. Finally, the small influence of shear deformation on the total deflection of these beams is illustrated.

This paper presents the experimental study of concrete beams in bending, externally strengthened with Textile Reinforced Cementitious materials (TRC) with varying contact area with the concrete. In order to study the pure influence of the TRC on the concrete substrate, only non-internally-reinforced concrete beams are considered. The crack pattern evolution is monitored with Digital Image Correlation, and the influence of the contact width between the concrete substrate and the external reinforcement is investigated. The results show that the TRC reinforcement has an important crack bridging capacity, and consequently that its application over the full beam width is beneficial for the loadbearing capacity and the limitation of the crack widths of the concrete beam.

The construction industry currently shows an increasing interest towards composites. However, despite their high mechanical capacity to weight ratio their practical use in construction remains rather limited, the relatively high cost often being mentioned as the most restricting factor. This paper demonstrates how this need for minimization of both cost and mass can be tackled by a multi-objective optimization. First, a two-objective size optimization procedure is developed, and subsequently its strength is illustrated on hybrid composite-concrete beams. An original methodology combining Non-dominated Sorting Genetic Algorithm (NSGA-II) and a meta-model is used to find all optimal solutions. The optimization algorithm moreover gives insight on the influence of different parameters such as the span and the concrete class on the weight and cost of the beams, and the dominance of certain design constraints in various locations of the design space.

Fire-testing of Textile Reinforced Concrete (TRC) is an interesting field in which quite limited research has been conducted so far. In this paper some preliminary tests are presented, where mortars used as binders are heated to 850 °C and their residual strength is tested, while the Ultrasonic Pulse Velocity (UPV) is also measured, before and after heating, and compared. Additionally, TRC specimens are subjected to flame exposure with a simple set-up and the residual strength is also tested by flexural tests. It is concluded that even with simple set-ups, interesting results can be obtained regarding the structural degradation of the material.

Loadbearing sandwich panels used as wall elements are a promising development since they combine structural and energy efficiency. Composite behaviour needs to be ensured so that the sandwich panel works as one element under a flexural load (meaning that the shear forces due to bending are transferred from one face to the other). To assure this full composite behaviour, an investigation of the bond strength between the faces and the core of the sandwich panel is necessary. Therefore, two different bond test set-ups were performed on sandwich panels with Textile Reinforced Cement (TRC) faces and an Extruded Polystyrene (XPS) insulating foam core. The two bond test set-ups were compared and revealed that one of the set-ups showed a combination of bond and shear failure of the core so that a clear conclusion on the bond strength couldn’t be obtained. The second set-up showed clear bond failure and gave a good estimation of the bond strength between TRC and XPS.

Textile reinforced cements (TRC), combining a cementitious matrix with fibre textiles, are a well-researched subject in literature. The material offers several advantages such as the design of low-weight, slender structures. However, one of the main drawbacks of this composite material is the time consuming manufacturing process using two dimensional fibre textiles. Three dimensional fibre textile architectures offer a solution to this problem, while retaining the TRC advantages. Most 3D fibre textiles use distance holders to bridge two, or more textile layers at a certain distance from each other. The influence of this distance holder on the mechanical properties of the whole TRC remains relatively unstudied in literature and will be the research topic of this paper. This research will present the results of three point bending experiments, performed on short TRC beams with a length to thickness ratio of approximately 4 to 1. A comparison is drawn between 3D TRC with fully operational 3D fibre textiles and 2D TRC with the same textile geometry and orientation, but without distance holders. A positive influence on the flexural response is witnessed for the 3D fibre textile, with an increased flexural stiffness up to 35%.

This work presents the characterisation of the local low velocity impact behaviour of a high-performance fibre reinforced cementitious composite (HPFRCC) made of phosphate cement and different types of E-glass textile reinforcements. The so called "energy profiling method" that was used for quantitative characterisation is adopted from Liu et al. (2004) who introduced this methodology on polymer matrix composites (PMC). A series of plates reinforced with chopped strand E-glass fibre mats (fibre volume fraction of 24%) was impacted during drop weight tests, showing that this methodology is as well applicable to textile reinforced cementitious composites. Further, the effects of impactor size and plate thickness were investigated experimentally, and finally the obtained results were compared to literature data for polymer matrix composites. (C) 2017 Elsevier Ltd. All rights reserved.

The last couple of years, the importance and potential of textile reinforced cementitious composites (TRC’s) has been investigated and proven in literature. The research has mainly been performed on thin-layered specimens made of individual fibre textile layers impregnated by a matrix. The drawback of this manufacturing technique however is the time-consuming process. A solution is the transition towards a three dimensional, rigid fibre textile, fully immersed in the matrix, which would drastically decrease the production time and thus improve the market uptake of these materials. In this paper, the mechanical properties of 3D textile reinforced cements are investigated. Experimental tensile and bending tests performed on these 3D TRC’s are discussed. The bending behaviour of the 3D TRC’s is compared to that of a 2D TRC with similar textile architecture. In the bending experiments, a clear stiffness difference in post-cracking stage is witnessed between the 3D TRC’s and the equivalent 2D TRC’s. This study serves as a foundation for a benchmark analysis comparing 3D fibre textiles to 2D fibre textiles in terms of manufacturing process and mechanical properties.

A structure that can transform from a compact bundle of scissor units to a fully expanded structural configuration is called a deployable scissor structure. Although these structures have numerous advantages over traditional structures (lightweight, compact, high-volume expansion) their practical realisation is quite limited due to their complex design process and high displacements. Research on their geometric and kinematic behaviour is ongoing; however, research on the use of barrel vault shaped scissor structures for real-life shelter applications, fully loaded as described in the European Standards, is absent. In this paper, in order to enhance the understanding and the use of scissors structures for disaster relief the structural behaviour of barrel vault shaped scissor structures is discussed and analysed. The paper analyses the deformation, the internal forces and the stress distribution of the scissor elements of a barrel vault shaped scissor structure under wind and snow loading. The paper provides the readers with insight in the structural behaviour of barrel vault scissor structures when used as a shelter, helping them making judicious choices for the design parameters and promoting the application of these innovative and promising structures for temporary use.

To enable the use of sandwich panels with Textile Reinforced Cementitious composite faces for the renovation of existing dwellings, a proper understanding of the structural behaviour of such panels is indispensable. In this paper, the influence of the cementitious matrix on the global flexural behaviour of the sandwich beams was quantified experimentally. Four-point bending tests were performed to evaluate the stiffness and structural capacity of the sandwich beams. Results show that the flexural behaviour of the beams is strongly dependent on the behaviour of the TRC faces. A numerical model was developed and is able to give a close prediction of the experimental results.

Shells in textile reinforced concrete (TRC) can be made very thin thanks to their non-corroding reinforcement. Consequently, buckling becomes an important parameter. Because of the lack of data in literature, this paper presents the experimental and numerical analysis on the buckling behaviour of a TRC dome (2 m span, 0.2 m height, 3.7 mm thick), which is subjected to a uniform pressure load until it buckles. This experiment is simulated using the Riks method in Abaqus and implementing geometrical imperfections. The simulations correspond well to the experimental data and validate the model, which enables the prediction of buckling, necessary when designing thin TRC shells.

Textile reinforced cement (TRC) is a composite material being increasingly used for load bearing applications. Damage in TRC as in all cementitious materials is an important issue in civil engineering. Acoustic emission (AE) exhibits promising outcomes in laboratory and in in-situ monitoring applications. Evaluation of the fracture mode is crucial as generally, shearing phenomena occur later than tensile (bending) cracking and indicate more severe damage. The acoustic signatures of the damage modes influence most of AE parameters including the average frequency AF and RA-value. However, there are no universal classification boundaries between tensile and shear signals mainly due to geometric effects, material properties, as well as sensor location and response function. In order to highlight this problem and discuss the possibility of a solution, the study occupies not only with the evaluation of the damage mode based on AE parameters but in addition uses multiple sensors to investigate the effect of the wave propagation distance. This is crucial in thin cementitious laminates since damping, scattering, reflections and plate wave dispersion seriously distort the signal having a strong effect on the classification result. It is seen that the classification boundaries between tensile and shear fracture should incorporate the information of propagation distance. (C) 2017 Elsevier Ltd. All rights reserved.

Loadbearing insulating sandwich panels with Textile Reinforced Cement (TRC) faces can combine the structural and insulating performance of a conventional wall configuration in one lightweight element. This makes them very suitable as a new type of wall element for low- and high rise residential buildings. By combining 2D and 3D textiles in the TRC faces the performance of the panels can even be improved. This paper presents a preliminary investigation of the buckling behaviour of large-scale sandwich panels with combined 3D and 2D TRC faces. The large-scale experiment is compared with an analytical model. This paper shows that further in depth investigations are needed with regard to the experimental test set-up (boundary conditions) in order to establish a better agreement with the analytical model.

Using large lightweight prefabricated sandwich panels for the renovation of existing dwellings facilitates the installation process and reduces the renovation time to a few days. To guarantee the performance of the panels during their entire life span it is necessary to evaluate their behaviour on the long term. During their life span the facade panels are exposed to weather conditions such as wind, snow, rain, etc. To simulate these effects 8 sandwich beams, with a span of 2.2 m were fabricated and loaded until failure, after being subjected to repeated mechanical loading and/or and heat-rain cycles. The latter were done in a climate chamber according to ETAG004. The results of this study show that repeated loading reduces the initial stiffness of the panels up to 40%. Durability tests (heat-rain cycles) did not influence the stiffness noticeably but led to a decrease of about 30% in ultimate strength when compared to a non-aged panel.

Lightweight composite-concrete beams are advantageous in terms of installation, but their mechanical and fracture behaviour is not easy to predict due to their inherent heterogeneity. In the present study hybrid beams made of Textile Reinforced Cement (TRC) hollow boxes reinforced with a Carbon Fibre Reinforced Polymer (CFRP) strip and a concrete layer on top are subjected to bending. Their fracture behaviour is complicated as they can suffer from multiple failure mechanisms: matrix cracking, interface debonding or delamination. Herein, their mechanical performance is evaluated and monitored by Acoustic Emission (AE) and Digital Image Correlation (DIC). AE indices show that beams suffering from one single failure mechanism (cement cracking) exhibit nearly constant AE characteristics throughout loading. Beams additionally suffering from delamination exhibit longer AE waveforms of lower frequency compared to the pure matrix cracking. These tendencies are obvious from the initial part of the test, enabling predictions about the subsequent failure. More importantly and for the first time in related literature, the use of DIC enables to relate AE to the strain fields during loading, the final damage pattern and the ultimate failure mechanism.