The viability of using Juncus acutus fibers as reinforcement material for developing lightweight sustainable non-structural construction materials in compliance with the valorization of local by-products has been investigated in this work. This study aims to investigate the effect of the chemical treatment of Juncus acutus fibers on the mechanical and hygric properties of bio-sourced clay–sand–Juncus acutus fiber composite. This lightweight specimen has been produced from a mixture of 60% natural clay and 40% sand by mass, as a matrix, and reinforced with different amounts of Juncus fibers. The fibers were used as a partial replacement of sand in the mixture by volume at 0% (control specimen), 5%, 10%, and 20%. In order to enhance interfacial bonding between the fibers and the binder matrix, which seriously limits the strength development of the composite, the fibers have undergone an NaOH alkali treatment with different concentrations of 1 and 2 wt. %. Morphological and elementary chemical component evaluations based on SEM micrographs and EDX analyses revealed that the 1 wt. % NaOH alkali treatment exhibited the most beneficial effect due to the removal of impurity deposits without significant surface damage to the fibers. This finding was highlighted through the tensile tests carried out which showed the tensile stress value of 81.97 MPa compared to those of the treated fibers with 2% NaOH (74.45 MPa) and the untreated fibers (70.24 MPa). However, mechanical test results, carried out according to the European Standard EN 196-1, highlighted the beneficial effect of the fiber alkali treatment on both the compressive and flexural strengths, particularly for the fiber contents of 5% and 10%, which corresponds to a strengthening rate of 25% and 30%, respectively. The examination of the hygroscopic properties of the samples, including capillary water absorption, water diffusivity, and moisture buffering capacity under the dynamic conditions have indicated that the specimen containing treated fibers exhibited a better moisture regulating property than that obtained with untreated fibers. However, the specimens with treated fibers are classified as excellent hygric regulators based on their moisture buffer values (MBV > 2 g/(m2.%RH)), according to the NORDTEST classification. The results also indicated that the capillary water absorption and the apparent moisture diffusivity of composites were lowered due to high fiber-matrix interfacial bond after fiber treatment. Consequently, the composite with treated fibers is less diffusive compared to that with untreated fibers, and thus expected to be more durable in a humid environment.

This work aims to investigate the impact of chemical treatment of Juncus acutus fibers on the hygric and mechanical performances of an innovative bio-sourced clay-sand-Juncus acutus fibers composite. This lightweight specimen has been produced from a mixture of 60 % natural clay and 40 % sand by mass, as a matrix, and reinforced with different amounts of Juncus fibers. The fibers were used as a partial replacement of sand in mixture by volume at 0 % (Control Specimen), 5 %, 10 %, and 20 %. In order to enhance the fiber-matrix interfacial bound, the raw fibers have undergone an NaOH alkali treatment with different concentrations of 1, and 2 wt. %. Morphological and mineralogical evaluation based on SEM micrographs and EDX analyses revealed that, the alkaline concentration of 1 wt. % is the optimized one for natural fiber surface modifications (removal of impurities without any surface damage). This optimal concentration is confirmed by tensile strength tests, showing that the treated fibers with this alkali solution presents the higher tensile stress value of 81.97 MPa, compared to those of treated fibers with 2 % NaOH (74.45 MPa), and the untreated fibers (70.24 MPa). However, mechanical test-results highlighted the benefit effect of the fiber alkali treatment on both the compressive and flexural strengths, particularly for fiber contents of 5 % and 10 %, which corresponds to a strengthening rate of 25 % and 30 %, respectively. Results also showed that the sample containing treated fibers exhibited a better moisture regulating property than that produced with untreated fibers. The specimens are classified as excellent hygric regulator based on their moisture buffer performance (MBV > 2 g/(m2.%RH)), according to NORDTEST classification. Results also indicated that the capillary water absorption and the apparent moisture diffusivity of composites was lowered due to high fiber-matrix interfacial bound, after fiber treatment. Consequently, the composite with treated fibers is less diffusive compared to that with untreated fibers, and thus expected to be more durable in a humid environment. These results were confirmed by morphological analysis of fibers-matrix interfacial transition zone.

Sand plays a very important role during the manufacture of concrete and mortar for the need of civil engineering and building. It influences both the properties of cementary materials in the fresh state and in the hardened state. The objective of this work is the development of self-compacting mortars with the various sands existing in the region of the city of Mascara for the main study of mechanical performance. Six sands were used for this purpose: three natural sands and three crushed sands. The tests carried out during this research are: physical tests, tests in the fresh state and tests on hardened mortars. The results to which our research has led is that self-compacting mortars made with crushed sands give a granular skeleton with high compactness and superior mechanical performance compared to self-compacting mortars made with natural sands.

The rammed earth or Pise is one of construction techniques that presents many advantages of availability, inexpensiveness of production costs and potential resources with a very low carbon footprint, and more importantly its low energy consumption. The goal of this work is to investigate the influence of hemp particles on the performance improvement of rammed earth, especially thermal properties, related to the thermodynamic behavior of the building in terms of efficiency and sustainability. The simulations of this preliminary experimentation aim at the physical and mechanical characterization of the soil and hemp mixture. The present work aims to determine along the advantages, the issues that can be produced during the formulation of rammed earth and hemp mixture, also the result of the study would help to the determination of the appropriate sample with the adequate formulation (percentage of Hemp) basing on the results of the used characterization. The challenge is in the use of local materials in building for energy efficiency and environmental, economic and social sustainability. Copyright (c) 2022 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the 3rd International Congress on Materials & Structural Stability.

The viability of using vegetable Ampelodesmos Mauritanicus (Diss) fibers to develop lightweight construction material was investigated in this paper. The objective of this work is to assess the physico-mechanical properties of Diss fibers reinforced concrete sample with fibers to binder volume ratio ranged from 0 (control specimen) to 4. In order to mitigate the inhibitory effect exerted by vegetable materials on binder hydration, Diss fibers were treated with hot water, while air lime-based binder has been selected to replace traditionally used cementitious binder. The most important part of this work is focused on the efficiency of using air lime-based binder to develop lightweight construction material containing Diss fibers. Air lime-based binder is the chosen variety of binder due to its abundance and low emissions from its manufacture. The experimental investigation of the chemical compatibility between treated fibers and binder through the hydration-test has shown the effectiveness of boiling water treatment on the modifications of morphological and mineralogical properties to overcome the inhibitory effect exerted when non-treated Diss fibers were used. The hardened specimen properties included dry density, porosity, compressive and flexural strengths, and elastic behavior have been studied. The results have indicated that despite a reduction in compressive strength, the reinforced specimen remains acceptable to be used in lightweight construction applications, as regards its compressive strength-value and lightening level. The flexural strength of reinforced specimen was found to be significantly enhanced. Depending on the amount of Diss fibers used in the mixture, it was found that the optimal addition of Diss fibers is in the range of 3 volumes content. The corresponding flexural strengthening rate has reached a value of 86.5 % higher, due to the several reinforcement mechanisms like the compaction process, Diss fiber bond reinforcement, and also the undisturbed development of hydrate components of air lime-based binder during hardening. Therefore, the addition of Diss fibers generates failure mode change of specimen from the brittle to ductile behavior, which results in improvement of deflection and toughness capacity.

The Algerian dams are in a more or less silted state. Fergoug dam is the most silted dam since it records a rate of siltation of 95%. The siltation of the dam is undoubtedly the most dramatic consequence of the problem of erosion in Algeria. The investigations are at two levels: either prevent the solids to arrive in the dam (that is to put obstacles to break the forces of the runoff water, but we can only hope partial results) or the evacuation of sediments by appropriate management of bottom. But in our opinion, their valorisation in the field of construction is the most appropriate solution. This valorisation helps protect the environment and natural materials. Many mud treatment methods are often used to improve the insufficient geotechnical properties before reuse for a certain function in the structure. Lime treatment is one of the most common methods of converting soils to new materials that provide the desired performances. The objective of this work is to study the mud behaviour of the Fergoug dam (Algeria) for its use in the application of road engineering. The study consists of reconstituting samples of the Fergoug dam mud with various proportions of lime in the laboratory and subjecting them to various tests (Proctor, VBS, CBR index, DRX, etc.). The results obtained are encouraging and therefore allow the valorisation of sediments of the Fergoug dam which are a cumbersome waste for the environment.

The study reported in this paper was undertaken to investigate the feasibility of lightweight construction materials, based on vegetable fibres. This innovative material consisted of mixture of natural clay (60%) and natural sand (40%) reinforced with different levels of fibers extracted from Jancus acutus "Smar". The fibers were used as partial replacement of sand in mixture by volume at: 0% (Control Specimen), 5%, 10%, and 20%. The objective of this work is to evaluate the physico-mechanical properties, through the examination of materials lightning, mechanical strengths (compressive and flexural). Due to the high hygroscopic nature of the vegetable fibers, the thermal conductivity of the composite materials was measured at both wet and dry state at different volumes of Juncus fibers replacement. Test-results have shown that the addition of 20% fibers decreased the composite bulk density from 1900 kg/m(3) to 1100 kg/m(3), which results in a high reduction of mechanical performances in terms of compressive and flexural strengths. The experimental investigation of thermal behaviour of this composite has shown that the increase of fibers volume leads to a significant decrease in thermal conductivity. For a composite containing 20% of fibers replacement, the dry thermal conductivity decreased from 0.902 W/m.K for control specimen (without fibers) to a value of 0.327 W/m.K. However, at wet state, the corresponding thermal conductivity decreased from 1.543 W/m.K to 0.361 W/m.K. Despite the decrease in mechanical strengths, the resulting composite can thus be considered as a promising candidate for use in thermal insulation material, because a conductivity of 0.350 W/m.K is generally considered as the worst acceptable value for insulating building material. (C) 2019 Elsevier Ltd. All rights reserved.

The production of calcined mud, with pozzolanic properties, from the large quantities of sediments dredged from Algerian dams, could be a good opportunity for the formulation of high performance mortars and pozzolanic concretes, with lower costs and less greenhouse gas (CO2) emissions. The optimal temperatures selected for calcination were 750, 850 and 950°C. The burning operation was continuous over a period of 3h. Therefore, a series of physical, chemical, mechanical and microstructural analyses were conducted on sediment samples, collected from the waters of Fergoug dam. The results obtained from the analyses of the calcined mud, from the dam, allowed saying that mortars with different percentages of that mud represent a potential source of high reactivity pozzolanic materials.

Cement is a strategic commodity in the civil engineering for the construction of reinforced concrete structures. But its production generates around 5% of toxic gases such as CO2 responsible for environmental degradation. Furthermore, cement industry is a consumer sector of non-renewable energy. The use in the cement of natural additions is a solution to reduce the CO2 gas and the cost of production. The purpose of this work is the study of a sustainable building material: natural pozzolan Beni-saf (PNB) incorporated to mortars exposed to sulfate attack (5% Na2SO4). The loss of mass, monitoring the pH reading of each attack solution as well as specimens dimensions are different tests to study the durability of mortars made with 10, 20 and 30% of natural pozzolan. The result derived from this research is that pozzolan improves mortars resistance to sodium sulfate environment.

In this paper an investigation of the thermal conductivity of a lightweight construction material containing rubber waste particles, is presented. Measurements were carried out in a dry state using a transient plane source (TPS) technique. To determine the effect of the rubber particles ratio on the thermal conductivity of a cement composite, 10%, 20%, 30%, 40% and 50% rubber particle ratios by volume as replacement to cement, were used. The experimental investigation revealed that the addition of rubber particles reduces the material unit weight, furthermore, thermal conductivity of the composite has been improved. The thermal insulating effect of rubber particles is most attractive and indicates a high and promising potential for development. Based on the self consistent method and assuming that the tri-phase composite consists of air, rubber particles and cement paste, thermal conductivity of the composite has been predicted as a function of the dry unit weight and formulations, using auto-coherent homogenisation model. The model requires the knowledge of rubber particles conductivity, which was experimentally measured using Horai and Simmons technique. A modelling application reveals good correspondence with the experimental results.

The purpose of this study was to investigate the potential utilisation of flax by-products in cementitious matrices, as aggregate additives, to develop lightweight construction materials that could be used for load-bearing walls. A material containing different amounts of flax particles, ranging from 0% to 10% as partial replacement of cement, was aerated by artificially entrapping air voids by means of a protein air-entraining agent. The composites were characterised by destructive and non-destructive testing. Analyses were made regarding the inhibitory effect of flax particles on hydration of cement, and the properties of the fresh and hardened composite. The results of hydration test have shown that an increase of flax particles in the cement matrix increases the inhibitory effect on cement hydration with a long setting time of the composite. For a specific mix with 10% of flax particles replacement, the corresponding inhibitory index-value of 57.5% classifies the mixture as being of “high inhibition”. However, the use of calcium chloride reduced the inhibitory effect on cement hydration, resulting in a “low inhibition” classification. Results from tests performed on fresh composite have shown attractive properties such as improvements in workability and air-entrainment with increasing flax particles. Study of the hardened composite obtained from oven dried specimens has indicated a significant reduction in sample unit weight, along with compressive strengths compatible with the basic requirement of lightweight construction materials, corresponding to RILEM “class III” recommendations. The reduction in flexural strength was lower than that in compressive strength. The results have also shown a high reduction in the dynamic elastic modulus, which indicates a high level of sound insulation of the composite.

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy

The main objective of this study was to investigate the potential utilisation of rubber waste in cementitious matrix, as fine aggregates, to develop lightweight construction materials. Composites containing different amounts of rubber particles, as partial replacement to cement by volume, were characterised by destructive and non-destructive testing. Five designated rubber contents varying from 10% to 50% by volume were used. The 28-days physical, mechanical and hydraulic transport properties of the cement composite were determined. Analyses included dry unit weight, elastic dynamic modulus, compressive and flexural strengths, strain capacity, and water absorption. Test results of the physico-mechanical behaviour indicated that the increase in rubber content decreases the sample unit weight with a large reduction in the strengths and elastic modulus values of the composites. Results have only shown that the introduction of rubber particles significantly increases the strain capacity of the materials. However, rubbers into cement paste enhances the toughness of the composite. Although the mechanical strengths were reduced, the composite containing 50% of rubber particles satisfies the basic requirement of lightweight construction materials and corresponds to “class II”, according to the RILEM classification. Test-results of the hydraulic transport properties revealed that the addition of rubber particles tends to restrict water propagation in the cement matrix and reduces water absorption of the composite. The decrease of the sorptivity-value is favourable to the durability of the specimen structures.

In this work, the idea is to use rubber waste particles as a raw material, to develop a new lightweight construction materials. The objective of the research reported in this paper is to investigate the physico-mechanical properties of Aerated Cement-Rubber Composites (ACRC), based on rubber particles. The volume content ratio of the rubber particles ranged from 0% to 50%. The aerated composite was produced using a new type of proteinic air-entraining agent, in accordance with a specific aerating process derived in the laboratory. The aerated composite was produced to be used in cellular concrete applications. Results from tests performed on fresh aerated composites have demonstrated many attractive properties, such as improved workability and a high stability of air bubbles within the matrix. A study conducted on hardened composite properties has indicated a significant reduction in sample unit weight, thereby resulting in a level of compressive strength. The composite satisfies the basic requirement of construction materials, and could be used for insulated load-bearing wall this study has also highlighted the effect of the proteinic air-entraining agent on the cementrubber interaction system, as regards the composite’s compressive strength. However, an examination of the composite’s water capillary absorption reveals that the addition of rubber particles tends to restrict water propagation and reduce water absorption; sorptivity values decrease with increasing rubber particles content. Cette étude concerne l’évaluation des propriétés du composite cellulaire ciment-caoutchouc, élaboré à base de poussières de caoutchouc pour des teneurs allant de 0 à 50 %. L’allégement a été effectué suivant un procédé d’allégement par moussage protéinique, mis au point au laboratoire, en vue de l’utilisation du composite dans le domaine d’application des bétons cellulaires. L’étude du composite à l’état frais a montré une amélioration de la maniabilité, avec une bonne stabilité des bulles d’air dans la matrice. L’étude du composite à l’état durci a montré une nette réduction de la masse volumique, avec des propriétés mécaniques compatibles avec l’utilisation en isolant porteur. L’effet de l’agent entraîneur d’air protéinique sur les liaisons matrice/caoutchouc dans la résistance du composite a été mis en évidence. L’étude de l’absorption par capillarité du composite a montré que l’ajout de poussières de caoutchouc réduit la sensibilité à l’eau du composite.

: This study has been undertaken for the purpose of investigating the physicomechanical properties of rubber dust generated from an aerated cement-rubber composite (ACRC). The volume content ratio of the rubber particles encountered ranges from 0% to 50%. The aerated composite was produced using a new type of proteinic air-entraining agent, in accordance with a specific aerating process derived in the laboratory. This material was developed for use in applications involving cellular concrete. Results from tests performed on fresh aerated composites have demonstrated many attractive properties, such as improved workability and a high stability of air bubbles within the matrix. A study conducted on hardened composite properties has indicated a significant reduction in sample unit weight, thereby resulting in a level of compressive strength compatible with an insulated load-bearing wall. INTRODUCTION MATERIALS AND EXPERIMENTAL TESTING RESULTS AND DISCUSSON CONCLUSIONS REFERENCES

The transport properties of building materials exposed to an aggressive environment represent the essential parameters affecting their durability. Furthermore, the deterioration process of materials is highly related to the movement of water contained in a porous volume, whether in liquid or vapour form, and to the air permeability. The present study has been undertaken to examine the influence of rubber aggregates on the durability factors of cement–rubber composites. Results reveal the importance of the cellular character of rubber aggregates with respect to the composite’s behaviour in contact with fluids.

The study presented herein has been undertaken in order to examine the physico-mechanical properties of cement–rubber composites by use of two types of rubber aggregates, in the aim of developing a highly deformable material. The results obtained highlight the importance of the alveolar feature and the elasticity of the rubber aggregates in helping improve the flexural strength and deformability of the material. An optical analysis reveals the best level of bonding between the expanded rubber aggregates and the cement matrix.

The accumulation of rubber waste represents an increasingly-serious environmental problem in France. The present study has been undertaken to examine the feasibility and potential of using rubber aggregates in Portland cement. The effect of different amounts of rubber on the physico-mechanical properties and elastic behaviour of composites was investigated. The tests carried out included inhibitory index, slump, bulk density, compressive and flexural strength, elastic modulus, and brittleness index. It was observed that many properties of cement paste can be altered by adding rubber aggregates. The test specimens exhibited ductile failure with high plastic energy absorption, increasing flexural strength, and lower compressive strength. For the covering abstract see ITRD E109255.