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Starch/nanocellulose nanocomposite is of interest because of its potential applications in the field of biodegradable food packaging and biomedical applications thanks to its safe, biodegradable, fabricated by simple traditional methods, and cheap. The starch reinforced by nanocellulose significantly improved the physicochemical properties, especially the mechanical properties, thermal stability as well as barrier properties, compared to the starch matrix. With outstanding advantages compared to polymer nanocomposites derived from petroleum, the starch/nanocellulose composite is considered a potential agent for biodegradable food packaging and biomedical technology.

Building with earth is an ancient technique which has been the object of numerous studies during the last decade, due to sustainable properties of the material. To improve the mechanical properties and the durability of earthen material, hydraulic binders are usually added (e.g. cement or lime). Other binders with lower carbon footprint are investigated to reduce the environmental impact of stabilised earth material. The present paper investigated a geopolymer-stabilised compacted earth (GSCE). The geopolymer was obtained by using fly ash and an alkaline activator solution (a mixture of Na2SiO3 and NaOH). First, a parametric study was performed to identify the important factors to be investigated. Then, 360 specimens were manufactured and tested under uniaxial compression, to investigate influences of different factors on the compressive strength: Na2SiO3/NaOH ratio (1, 1.5 and 2); the mixing procedure; curing temperature (ambient, 60 and 90 °C) and evolution of compressive strength as a function of time (7, 14, 28, 56, 90 and 180 days). The scanning electron microscopy, X-ray diffraction and Fourier-transform infrared spectroscopy techniques were applied to investigate the microstructure of GSCE specimens. The geopolymerisation in the specimens was verified by using these techniques. It was shown that the chemical bond C-H (a product of reactions between the activator and CO2 in the air) influenced the evolution of the compressive strength in function of time. The results showed, that after 28 days, the compressive strength of GSCE continued to increase 20–25% until 56 days. The unstabilised and cement-stabilised specimens were also tested and compared with GSCE specimens.

In the context of novel environmental and energy regulations in construction (RE2020), biocomposites derived from bamboo fibers, bamboo powders, and biodegradable poly(lactic)acid polymer, all of which are renewable resources, have been investigated to meet the criteria of the novel regulations. In this work, the biocomposites were manufactured by twin-screw internal mixing at 170 °C for 5 min with a rotation speed of 60 rpm. The composites sheets were then shaped on a hydraulic press at 185 °C. Pore characterization including pore volume fraction, 3D-pore structure and morphology, and pore distribution of these materials were investigated using X-ray tomography combined with image processing (Avizo). The results show that when the bamboo fibers content is increased, an augmentation in the pore volume fraction and the number of large-volume pores could be observed. In turn, the bamboo powder-containing sheet had a significant increase in pore volume fraction, while a higher quantity of smaller pores, with uniform size, could be observed. The water absorption capacity of these composite increases with the increase of the amount of pore distribution, pore connection, and pore volume fraction. In addition, the orientation of the fibers in 3D observation, flexural mechanical properties, and thermal stability of the biocomposites are also reported in this study.

This paper describes the effect of inorganic adsorbents on the hygrothermal performance of insulating materials. The addition of the inorganic adsorbents leads to significant effect to the microstructure and mechanical properties of these materials. The thermal conductivity rang of the materials containing adsorbents from 0.095 to 0.116 (W/m−1 K−1) is lower than that of those without adsorbents (0.121 (W.m−1 K−1)), resulting in reducing the heat consumption of these insulation materials. The kinetics and isotherms water vapor adsorption confirm an increase in moisture uptake capacity at low relative humidity (33%) and small variation of moisture adsorption capacity at high relative humidity (75%) in the presence of the adsorbents. The moisture buffering of the boards containing different adsorbent contents is improved with an excellent moisture buffer value up to 2.7 g/(m2.%RH).

Rammed earth (RE) is a sustainable material which is made by compacting the soil in a formwork. The earthquake performance of RE structures is an important topic, however the out-of-plane seismic behavior of RE structures has not been thoroughly investigated in the literature. The objective of the present paper is to study the out-of-plane seismic behavior of RE walls by using finite element method. The model used involved the concrete damage plasticity (CDP) model to simulate the nonlinear behavior of the earthen layers, a surface-based cohesive behavior to simulate the linear and nonlinear behavior of the interlayers (between the layers). The parameters of the model were first validated through the simulations of available experimental tests in the literature for both in-plane and out-of-plane loading. Then, a U-shaped RE wall was modelled which was composed of one longitudinal wall (4.6-m-length × 2.4-m-height × 0.5-m-thickness) and two transversal flanges (2-m-length). Effects of the bond beam (on the top of the walls), the interlayers and different earthquake amplitudes were studied. The results showed that the implementation of the interlayers in the model had clear influences on the ultimate load and the failure modes but the inter-storey-drift was few affected; the bond beam played an important role for the out-of-plane seismic behavior of the RE wall. The performance of the studied RE structure was satisfying until a seismic amplitude of 0.223 g.

A hierarchical nanostructure consisting of uniform copper oxide nanowires vertically grown on three-dimensional copper framework (CuO NWs/3D-Cu foam) was prepared by a two-step synthetic process. The uniform CuO NWs anchored onto the 3D foam exhibited outstanding electrocatalytic activity towards hydrogen peroxide reduction due to the unique one‐dimensional direction with its excellent catalytic activity and large surface area of 3D substrate, which enhanced electroactive sites and charge conductivity. As a result, a wide linear detection range of 1 µM–1 mM, good sensitivity of 8.87 µA/(mM ⋅ cm2), low detection limit of 0.98 µM, and rapid response time of 5 s to hydrogen peroxide were achieved under a working potential of −0.4 V in phosphate buffer solution (pH of 7.4). In addition, the CuO NWs/3D-Cu foam material showed excellent selectivity to hydrogen peroxide and good resistance against poisonous interferents, including ascorbic acid, dopamine, urea, uric acid, and potassium chloride. Furthermore, the CuO NWs/3D-Cu foam presented good reproducibility, stability, and accurate detection for hydrogen peroxide in real sample; therefore, it may be considered to be a potential free-standing hydrogen peroxide sensor in practical analysis applications. Keywords: Copper oxide nanowires, Three-dimensional substrate, Electrocatalyst, Hydrogen peroxide detection, Self-supported sensors

Earth is an ancient construction material that is attracting numerous scientific investigations due to the sustainable characteristics of this material and the significant heritage of existing earth constructions. Several studies have recently been conducted to investigate the seismic performance of earth buildings. This chapter presents the state of the art related to the seismic performance of earth structures. Since the seismic performance of a structure depends both on the dynamic and static characteristics of the material and the structure, the chapter starts with a summary of the static characteristics, followed by the results on the dynamic characteristics. Then the existing methods for the earthquake performance evaluation are presented. Finally, the techniques of seismic strengthening are cited and discussed. This chapter is a useful repertoire for further studies on the seismic design of earthen structures., This chapter is prepared in the case of the RILEM Technical Committee TC 279-TCE (Testing and characterisation of earth-based building materials and elements). The authors wish to thank the French National Research Agency (ANR) for funding the PRIMATERRE project (ANR-12-Villes et Bâtiments Durables). Several results presented in this paper are the outcome of this project. The funding from the ReBuMAT project (German-Vietnamese Collaborative Project on Resource-efficient Construction using Sustainable Building Materials) is acknowledged. Part of this work was also carried out within the framework of project POCI-01-0145-FEDER-016737 (PTDC/ECM-EST/2777/2014), financed by FEDER funds through the Competitivity Factors Operational Programme—COMPETE and by FCT—Foundation for Science and Technology. The funding provided is kindly acknowledged. This work was partly financed by FEDER funds through the Competitivity Factors Operational Programme—COMPETE and by national funds through FCT—Foundation for Science and Technology within the scope of project SafEarth (PTDC/ECM-EST/2777/2014).

This chapter reviews the potential impact of six environmental agents (water, ice, wind, fire, solar radiation and chemical attack) on the long-term stability of earth buildings together with some of the most common techniques for measuring and improving material durability. Liquid water appears the most detrimental of all environmental agents, not only because it can significantly reduce capillary cohesion inside the material but also because water can penetrate inside buildings through multiple routes, e.g. rainfall, foundation rise, ambient humidity and utilities leakage. Water can also be very damaging when it is present in solid form as the expansion of pore ice may induce cracking of the earth material. The high resistance of earth buildings to wind is instead proven by the good conditions of many historic structures in windy regions. Earth buildings also exhibit good resistance to fire as the exposure to very high temperatures may even improve material durability. Solar radiation has, in general, a beneficial effect on the stability of earth buildings as it promotes water evaporation with a consequent increase of capillary cohesion. Solar radiation may, however, have a detrimental effect if the earth is stabilised by organic binders that are sensitive to photodegradation because, in this case, it may produce material damages ranging from a simple surface discoloration to a much more serious deterioration of the intergranular bonds. Unstabilized earth is generally inert and, hence, largely unaffected by chemicals though, in some instances, the precipitation of salt crystals inside the pore water can induce material cracking. Chemical degradation can instead be severe in both stabilised earth (due to the dissolution of intergranular bonds) and steel-reinforced earth (due to the corrosion of rebars). No international standard protocol exists to measure the durability of earth materials, which is currently assessed by multiple experimental procedures depending on which environmental agent is considered. Testin, (undefined)

Portland cement concrete is a popular construction material but it has high carbon footprint and consumes significant natural resources. Using geopolymer and recycled concrete aggregates is an interesting approach to reduce the carbon footprint, the natural resource consumption. Limited studies in the literature have focused on geopolymer recycled aggregate concrete. This paper presents an investigation on the compressive strength of geopolymer concretes with natural and recycled coarse aggregates. An empirical model was proposed and evaluated for geopolymer concretes. The results showed that the proposed model could be used for the compressive strength predictions of geopolymer concretes, for both natural and recycled aggregates.

A novel nanohybrid based on palladium sulfide nanoparticles uniformly dispersing on heterostructure of MoS2/nitrogen-doped graphene (PdxSy-MoS2/N-GR) was developed for catalyzing oxygen reduction reaction in alkaline medium. The nanohybrid demonstrated effectively catalytic performance with a positive onset potential of −0.141 V and half-wave potential of −0.214 V, along with high current response, which are comparable to a commercial Pt/C product. In addition, the nanohybrid also exhibited good stability and excellent methanol tolerance, significantly superior to those of the Pt/C. The obtained results were assumed to the synergistic effects produced by PdxSy, MoS2, and N-GR to enhance numbers of electroactive sites and charge conductivity. In addition, the large surface area of the MoS2/N-GR heterostructure effectively accelerated the electrolyte penetration and diffusion rate of reactant. The outstanding catalytic performance of the PdxSy-MoS2/N-GR opens up a novel approach for developing efficient and cost-effective catalyst towards ORR in alkaline fuel cell applications.

Herein, we successfully fabricated a novel nanostructure based on hierarchical urchin-like FeCo oxide supported carbon spheres (FeCo Oxide/CSs) via a two-step hydrothermal method followed by a simple annealing step at 300 °C under air. It was found that such urchin-like FeCo Oxide/CSs structure exhibited superior catalytic activity towards hydrazine oxidation to CSs, Fe Oxide/CSs, Co Oxide/CSs, and FeCo Hydroxide/CSs material. In this regard, the FeCo Oxide/CSs displayed a wide linear detection range of 0.1–516.6 μM, low detection limit of 0.1 μM, and long-term stability. The material also showed good selectivity towards hydrazine detection in the presence of various interferences, such as uric acid, ascorbic acid, urea, dopamine, Na+, SO42−, K+, and Cl-. The excellent sensing performance of the FeCo Oxide/CSs was assumed to the unique hierarchical urchin structure with the high density and uniformity of nano-sized FeCo Oxide nanoneedles, which produced massive electroactive sites and enhanced charge transfer ability. The achieved results implied that the FeCo Oxide/CSs may be a great candidate for sensitive hydrazine detection.

Developing high-effectiveness electrocatalysts towards hydrogen evolution reaction (HER) is important for the friendly generation of hydrogen gas on a large scale through electrochemical water splitting. In this study, a hybrid nanostructure based on zinc-nickel phosphide nanosheets vertically grown on a three-dimensional Ni foam (ZnNi–P NSs/NF) was prepared through an easy hydrothermal approach followed by a phosphidization process at 300 °C. The unique nanoarchitecture with hierarchical pores is advantageous for exposing satisfactory active sites and offering evaluable structure and electronic properties. Particularly, the addition of certain Zn–P amount significantly alters electronic structure of the ZnNi–P NSs hybrid, thereby leading to accelerate electrocatalytic activity for HER in 1.0 M KOH. In this context, the ZnNi–P NSs/NF displays requires small overpotentials of 175 and 291 mV to deliver current densities of 10 and 50 mA cm−2, respectively, along with a small Tafel slope of 129 mV/dec, suppressing other synthesized materials and sufficiently reaching Pt/C catalyst. Furthermore, there is only minor reduction of current response and overpotential during continuous HER for over 1000 cycles, suggesting its impressive operation stability. The developed ZnNi–P NSs/NF with good catalytic activity and robust stability over the Pt/C catalyst can open a novel door for efficient water splitting technology.

A novel hybrid based on non-precious metal catalysts embedded into nitrogen doped graphene nanosheets was developed for oxygen reduction reaction (ORR) by pyrolyzing a mixture of Ni, Pd salts, nitrogen source, and graphene oxide. Scanning electron microscopy, transmission electron microscopy, Raman spectra, and X-ray photoelectron spectroscopy analyses indicated the binary NiPd nanoparticles good dispersed on nitrogen-doped graphene sheet (NiPd NPs/N-GR) under a unique core-shell nanostructure with high interaction, thereby creating massive catalytic sites and boosting the activity towards ORR in alkaline medium. The electrochemical measurements showed the onset and half-wave potential of the NiPd NPs/N-GR were +0.961 and + 0.82 V, respectively, indicating a comparable catalytic behavior to a commercial Pt/C product (20 wt%). In addition, such catalyst also exhibited superior stability and methanol tolerance ability to Pt/C. The achieved superiorities of the NiPd NPs/N-GR imply that this material is potential to replace Pt-based catalysts in for ORR applications.

A novel hierarchical heterostructure of molybdenum dichalcogenide nanosheets homogeneously assembled on nitrogen doped graphene layer (MoS2 NSs/N-doped GR) was successfully developed by an easy and cost-effective strategy. The MoS2 NSs/N-doped GR was then utilized for accelerating hydrogen evolution reaction (HER) in alkaline medium. It was found that the nanohybrid exhibited highly efficient catalytic activity towards HER with higher current density and smaller overpotential as compared to those of other synthesized materials. In this context, the nanohybrid required an overpotential of only 208 mV to achieve a current density of 10 mA cm−2, along with a small Tafel slope of 79 mV dec-1, which is close to those of a commercial Pt/C. An outstanding stability of the nanohybrid for long-term operation was also demonstrated. The obtained results suggest that the MoS2 NSs/N-doped GR nanohybrid can be a potential candidate for HER in overall water splitting application.

At present, dynamic measurements enable the diagnosis of an existing structure at a global scale (the whole structure), while the identification and assessment of local damage (at each elem...

We successfully developed a hybrid catalyst based on binary CuFe alloy nanoparticles (NPs) uniformly encapsulated within nitrogen-doped graphene nanosheets (CuFe NPs/N-rGO). The catalyst displayed excellent performance for oxygen reduction in 0.1 M KOH medium. In this context, the catalyst showed an onset potential of +0.99 V (vs. RHE), which is comparable to that of Pt/C catalyst. The fast ORR kinetic was also confirmed with high electron transfer number of 3.8–3.88. In addition, the catalyst demonstrated the superior stability and methanol tolerance to commercial Pt/C product. The enhanced ORR performance of the CuFe NPs/N-rGO hybrid is assumed to an efficient synergistic effect between CuFe NPs and N-rGO nanosheets. In particular, the formation of encapsulation structure in which CuFe NPs are wrapped by several layers of N-rGO not only improves charge transfer but also effectively avoids from the dissolution and aggregation of the active metal NPs, thereby improving active sites, reaction kinetic, and stability of catalyst. The results suggest that the CuFe NPs/N-rGO hybrid may be a promising noble metal-free ORR catalyst for alkaline fuel cell applications.

The fabrication of efficient and durable novel electrocatalysts using a facile and cheap way is a potential approach for real energy conversion technology. In this research, a novel nanohybrid based on iron nickel nanoparticles well attached on nitrogen doped graphene nanosheets (Fe2Ni1 NPs/N-Gr) was synthesized through a simple refluxing strategy followed by a calcination process. It was discovered that the material displayed good catalytic behavior for oxygen reduction reaction (ORR) in alkaline environment. The ORR kinetics of the material primarily occurred through a 4-electron transferred pathway consistent with high diffusion limit current density, excellent onset potential (−0.013 V) as well as half-wave potential (−0.065 V). Furthermore, the material showed good stability and outstanding methanol tolerance as compared to a commercial Pt/C catalyst. The resulting catalytic performance of the material was assumed to the synergistic effect from bimetallic Fe2Ni1 NPs and thin nitrogen doped graphene, which improved electroactive site numbers, promoted charge transfer ability, and adjusted adsorption energy for oxygen molecules. The results imply that such novel materials may be an effective and low-cost catalyst for ORR in energy conversion technology.

Rammed earth (RE) is a construction material which is manufactured by compacting soil by layers within a formwork to build a monolithic wall. RE material is the subject of numerous scientific researches during the last decade because of the significant heritage of RE buildings and the sustainable properties of this material: low embodied energy, substantial thermal inertia, and natural regulator of moisture. The seismic performance of RE buildings is an interesting topic which needs to be thoroughly investigated. This paper presents a numerical study which assesses the relevancy of a seismic reinforcement technique for RE walls by using two vertical steel rods installed at two extremities of the walls. The discrete element method (DEM) was used to model unreinforced and reinforced RE walls. These walls were first loaded with a vertical stress on the top to simulate the vertical loads and then submitted to a horizontal loading on the top to simulate the seismic action. Two current cases of RE buildings were investigated: one-storey and two-storey buildings. The results showed that the reinforcement technique enhanced the maximum horizontal force about 25% and 10%, respectively, for the cases of one- and two-storey buildings. Higher effectiveness of this reinforcement technique is expected for RE materials having higher compressive strength, for example, stabilized RE.

In this study, we developed a novel free-standing sensor based on hierarchical zinc-doped nickel hydroxide nanosheets vertically attached three-dimensional (3D) framework (Zn-doped Ni(OH)2 NSs/3DF) via a mild and facile hydrothermal reaction for non-enzymatic glucose detection. The Zn-doped Ni(OH)2 NSs/3DF-based sensor exhibited a good sensitivity of 52 μA μM−1 cm−2, wide linear detection range of 7.9 nM to 15.2 μM, and a low detection limit of 26.6 nM. Besides, the respectable selectivity and excellent stability of such sensor were also demonstrated. The achieved results were due to the formation of the Zn-doped Ni(OH)2 NSs, which played an important role for promoting the electroactive sites and surface area, leading to the improvement of electrocatalytic activity towards glucose oxidation. In addition, the successful fabrication of a unique self-supported 3D hierarchical architecture not only produced the enhanced charge conductivity but also assisted to the sensing stability because it effectively avoided the agglomeration or exfoliation of NSs. The remarkable sensing activity and stability of the Zn-doped Ni(OH)2 NSs/3DF-based sensor offered a facile and appropriate approach towards glucose detection, which is highly promising to apply for practical clinical analyses.

Small and uniform bimetallic WMoSx nanoparticles well distributed on surface of thin graphene nanosheets (WMoSx-Gr) was prepared and investigated as an effective electrocatalysts for oxygen reduction reaction (ORR) in alkaline electrolyte. This material exhibited highly catalytic activity relative to a commercial Pt/C product. In this context, the material showed a large limit current density, positive onset potential (−0.05 V) as well as half wave potential (−0.13 V). In particularly, the superior durability and methanol tolerance of the as-synthesized material were also pronounced, as compared to Pt/C. The high ORR activity of the WMoSx-Gr material was assumed to the synergistic effect produced from a unique nanostructure of the WMoSx and the high surface area graphene with its excellent conductivity. The obtained results imply that such hybrid material can open a new type of highly efficient non-Pt catalyst for ORR in alkaline environment.

Herein, we successfully developed a novel three-dimensional framework attached carbon nanotubes deposited with high density of gold nanoparticles (Au NPs-CNTs/3DF) through a facile method. The achieved hybrid with an opened hierarchical network was effectively used as a free-standing sensor for hydrazine detection. The catalytic activity of the proposed sensor was impressively higher than those of other surveyed materials, such as CNTs/3DF and Au NPs/3DF. In this regard, the much higher intensity of oxidation current density and negative peak potential were presented for Au NPs-CNTs/3DF towards hydrazine oxidation. Through amperometric measurements, the Au NPs-CNTs/3DF electrode displayed excellent performance for hydrazine determination with wide linear detection range of 0.5 to 483 μM, high sensitivity of 1.65 μA·μM−1·cm−2, a low detection limit of 1.1 μM, along with negligible interference effect. The obtained results suggest that the Au NPs-CNTs/3DF hybrid holds the great prospect for highly sensitive and selective determination of hydrazine in practical applications.

International audience; Rammed earth (RE) is a construction material which is manufactured by compacting the soil within a formwork, in superimposed layers. RE is attracting scientific studies because of its sustainable properties : a very low embodied energy and an advantageous living comfort due to a particular benefic hygro-thermal behaviour. Numerous studies have been conducted to investigate RE material and RE structures, however, a lack of knowledge on the seismic performance of RE buildings is noticed. This paper presents an advanced numerical study to investigate the in-plane seismic behaviour of RE walls. First, a numerical model of an in-situ RE wall was constructed by using discrete element modelling (DEM). The relevancy of the numerical model was verified by comparing dynamic properties of the model with that measured on the in-situ wall. Then, a real earthquake excitation was applied to the model, in order to evaluate the seismic performance of the RE wall studied. This is the first time, to our knowledge, that a dynamic discrete explicite analysis was performed for a RE wall. The excitation was scaled at different amplitudes to assess the damages following different earthquake intensities. The results showed that for seismic excitations lower than 2.3 m/s2, RE walls studied had satisfying in-plane earthquake performance.

Ordinary cement concrete is a popular material with numerous advantages when compared to other construction materials, however, ordinary concrete is also criticized from the public point of view due to the CO2 emission (during the cement manufacture) and the consumption of natural resources (for the aggregates). In the context of sustainable development and circular economy, the recycling of materials and the use of alternative binders which have less environmental impacts than cement are challenges for the construction sector. This paper presents a study on non-conventional concrete using recycled aggregates and alkali-activated binder. The specimens were prepared from low calcium fly ash (FA, an industrial by-product), sodium silicate solution, sodium hydroxide solution, fine aggregate from river sand, and recycled coarse aggregate. First, influences of different factors were investigated: the ratio between alkaline activated solution (AAS) and FA, and the curing temperature and the lignosulfonate superplasticizer. The interfacial transition zone of geopolymer recycled aggregate concrete (GRAC) was evaluated by microscopic analyses. Then, two empirical models, which are the modified versions of Feret’s and De Larrard’s models, respectively, for cement concretes, were investigated for the prediction of GRAC compressive strength, the parameters of these models were identified. The results showed the positive behaviour of GRAC investigated and the relevancy of the models proposed.

Based on the RILEM Technical Committee 274-TCE work, this paper is a discussion of the remaining engineering challenges faced by earthen architecture. The assessment of earth material performances requires the development of appropriate procedures and standards. This is discussed in particular for the characterisation, hygrothermal behaviour, mechanical behaviour, and durability of earth materials. One other important challenge, since one of the main advantages classically put forward, is its ecological performance, is a proper assessment of life cycle assessment of earth materials, elements and buildings. Moreover, the paper develops why the approach to earthen construction must be different compared to the dominant construction materials, to preserve its ability to contribute to the ecological transition in the construction sector. In particular, the needs of using local soils, with an architectural approach coping with the limits of the materials, and developing an architectural optimisation to preserve the earthen materials multifunctionality rather than selecting a sole property to be maximised. Lastly, the findings of the paper can be used to develop a holistic approach to earthen construction to foster the development of new earthen architecture projects.

The need for a vast quantity of new buildings to address the increase in population and living standards is opposed to the need for tackling global warming and the decline in biodiversity. To overcome this twofold challenge, there is a need to move towards a more circular economy by widely using a combination of alternative low-carbon construction materials, alternative technologies and practices. Soils or earth were widely used by builders before World War II, as a primary resource to manufacture materials and structures of vernacular architecture. Centuries of empirical practices have led to a variety of techniques to implement earth, known as rammed earth, cob and adobe masonry among others. Earth refers to local soil with a variable composition but at least containing a small percentage of clay that would simply solidify by drying without any baking. This paper discusses why and how earth naturally embeds high-tech properties for sustainable construction. Then the potential of earth to contribute to addressing the global challenge of modern architecture and the need to re-think building practices is also explored. The current obstacles against the development of earthen architecture are examined through a survey of current earth building practitioners in Western Europe. A literature review revealed that, surprisingly, only technical barriers are being addressed by the scientific community; two-thirds of the actual barriers identified by the interviewees are not within the technical field and are almost entirely neglected in the scientific literature, which may explain why earthen architecture is still a niche market despite embodying all the attributes of the best construction material to tackle the current climate and economic crisis. This article is part of the theme issue ‘The role of soils in delivering Nature's Contributions to People’.

This study aims to produce novel composite artificial marble materials by bulk molding compound processes, and improve their thermal and mechanical properties. We employed stearic acid as an efficient surface modifying agent for CaCO3 particles, and for the first time, a pretreated, recycled, polyethylene terephthalate (PET) fibers mat is used to reinforce the artificial marble materials. The innovative aspects of the study are the surface treatment of CaCO3 particles by stearic acid. Stearic acid forms a monolayer shell, coating the CaCO3 particles, which enhances the compatibility between the CaCO3 particles and the matrix of the composite. The morphology of the composites, observed by scanning electron microscopy, revealed that the CaCO3 phase was homogeneously dispersed in the epoxy matrix under the support of stearic acid. A single layer of a recycled PET fibers mat was pretreated and designed in the core of the composite. As expected, these results indicated that the fibers could enhance flexural properties, and impact strength along with thermal stability for the composites. This combination of a pretreated, recycled, PET fibers mat and epoxy/CaCO3-stearic acid could produce novel artificial marble materials for construction applications able to meet environmental requirements.

Vietnam is undergoing a continuing construction boom. This enormous volume of new constructions is characterized by simple building techniques and large consumption of materials. The Vietnamese government would like to reduce the use of traditional fired clay bricks to avoid inefficient brick production with high energy use, significant CO2 emissions, and the accompanying destruction of valuable agricultural land due to clay mining. The strategy is to switch to alternative wall-building materials in efficient industrial production methods. To support this development, the BMBF-funded project “CAMaRSEC” is developing a study on life-cycle assessment of building materials that provides the basis for sustainable resource management and avoiding hazards to the local environment. A key focus is the holistic investigation of the Production Stage of traditionally fired clay bricks as well as currently existing alternative wall-building materials (non-fired bricks). At present available data sets are mainly for developed countries and cannot be applied to the production methods in Vietnam. Therefore, there is an urgent need for local data sets generated within this project.

Bio-insulating materials are well known to reduce the environmental impact of constructions and are able to regulate the indoor temperature and humidity of buildings. This study investigates the influence of high-absorbing bio-glues based on a protein and lignin compound on moisture transfer and storage as well as on thermal performance of bamboo particleboards. The investigations are based on the moisture buffer value, vapor permeability, isothermal vapor sorption and thermal conductivity. Simultaneously, the mechanical properties and mold growth of these materials, manufactured for the study, are also investigated. The results demonstrate excellent moisture buffer capacity, from 2.13 to 3.26 g/(m2·%RH). The vapor sorption isotherm results exhibit the materials’ high moisture storage, and the vapor permeability behaves like commercial bio-insulating materials. The thermal conductivity of particleboards shows a low value, in accordance with their density and variation in moisture content. In addition, the results indicate mold appearance on the surfaces of specimens after 14 days exposure to 84% relative humidity. Moreover, a comparison of the hygrothermal characterizations between bamboo particleboards and fiberboards (Nguyen et al., 2017) is carefully made to highlight the exceptional features of those bio-boards.

In this study, a hybrid of titanium dioxide, benzophenone and ethylene vinyl acetate (TiO2-BP-EVA) was used as a novel catalyst to accelerate photo-oxidization reaction of low-density polyethylene (LDPE) film under ambient conditions. The degradation of the LDPE films (thickness of ~25 μm) containing different catalyst concentrations were successfully investigated by different techniques, such as Fourier-transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (SEM), differential scanning calorimetry (DSM), thermogravimetric analysis (TGA) and mechanical tests. The results showed that the use of catalyst in which TiO2-BP content (1/3 w/w) is 0.5 phr (parts per hundred resin) and EVA content is 4.5 phr in a LDPE film provided the best degradation rate. The carbonyl index of the polymer film achieved the highest value without an equilibrium stage. Besides, the carbon-carbon backbone of the polymer was completely broken down consistent with the deformation of the surface. In addition, the mechanical properties impressively dropped after 3 months’ exposure. The obtained results imply that the TiO2-BP-EVA compound can be considered as an efficient catalyst for the photodegradation of LDPE polymer.