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Item type:Publication, Optimization of a reinforced geopolymer composite using natural fibers and construction wastes(Elsevier, 2020-10-20)Geopolymer technology has allowed the development of eco-friendly construction materials with high mechanical properties using industrial wastes and residues. However, geopolymers show fragility and low ductility behavior similar to Portland cement-based materials. This article focuses on the evaluation of jute and sisal fibers as reinforcement of a geopolymer matrix produced from residues of Fired Clay Brick Powder (FCBP). Control samples with no fibers and reinforced matrices with different contents of jute (ranging from 0.5 to 2.0 wt%) and sisal fibers (ranging from 0.5 to 3.0 wt%) were produced to study the effect of the fiber type and content on the mechanical properties of the resulting geopolymer composites. Mechanical characterization consisted of compression, splitting tensile, and three-point bending tests. The results of compression and splitting tensile tests showed the existence of an optimum fiber content that depends on the fiber type for reaching the maximum strength while the three-point bending test results indicated a linear relationship between the flexural strength and the fiber content. The addition of 2.5% (wt%) of sisal fibers increased the compressive, splitting tensile and flexural strengths up to 76%, 112%, and 270%, respectively, in comparison to the control samples. On the other hand, FCBP-based geopolymers with 1.5% (wt%) jute fiber reinforcement showed an increase up to 64%, 45%, and 222% of the compressive, splitting tensile and flexural strengths, respectively. Both, jute and sisal fiber addition at the optimum content, lead to a change in the failure mode of the samples from a brittle to a more ductile failure in all mechanical tests. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Production of a lightweight masonry block using alkaline activated natural pozzolana and natural fibers(Elsevier, 2020-08-30)Lightweight geopolymers are alternative low-carbon footprint building materials with high potential to produce value added products for the construction industry such as low-density masonry units. This work focuses on presenting the development of a new lightweight masonry block using natural pozzolana-based geopolymer mortar, hydrogen peroxide as a foaming agent and jute fibers as reinforcement additive. The experimental plan allowed the optimization of the production process and the definition of the optimum quantities of hydrogen peroxide content, pozzolana: fine aggregate ratios and the appropriate amount of fibers to be incorporated. The experimental results demonstrate the feasibility of the production of new masonry units, which can achieve up to 8.1 MPa of compressive strength after 28 days of fabrication with reduced bulk densities of 1269 kg/m3. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Mechanical characterization of a masonry system made of alkaline activated pozzolana blocks(Trans Tech Publications Ltdttp@transtec.ch, 2020-01-01)The development of alkaline activated materials has enabled the production of eco-friendly alternatives for the construction industry. In the present article, the mechanical characterization of a new structural masonry system composed of fiber-reinforced lightweight pozzolana-based blocks and cement-lime mortar was performed. The mechanical characterization involved uniaxial compression tests in prisms and diagonal compression in wallets. The results indicate that the compressive and shear strength of the masonry system is up to 3.24 MPa and 0.38, respectively. The results obtained indicate that the evaluated system is structurally efficient and that can be used as both non-load and load-bearing walls. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Alkali-treated Agave americana fiber for reinforcement of fly ash-based geopolymers(Taylor and Francis Ltd., 2022-01-01)The mechanical properties of Agave americana fibers treated with NaOH solutions (1, 5, and 20 wt.%) for different times (0.5, 1 and 3 h) were investigated. At these conditions, tensile strength and ultimate strain of the fibers were determined. The treatment that required the minimum resources to improve the mechanical performance was 1% NaOH for 1 h. Fiber surface after the alkaline treatment was analyzed by scanning electron microscopy (SEM); it showed partial remotion of impurities at the mildest condition (1% NaOH for 0.5 h) and an apparent surface decomposition when using the most harsh condition (20% NaOH for 3 h). Fly ash-based geopolymer composites with different treated fiber contents were prepared. The compressive, flexural, and splitting tensile strengths of the composite geopolymers at seven days of age were determined. Results indicated that the addition of fibers slightly influenced the compressive strength; however, the ductility capacity was improved by up to 26% when 1% of treated fiber was incorporated. Regarding the tensile behavior, results indicate a direct relationship of strength with the amount of fibers, up to 36% improvement with 1% fiber content. Morphological of the fiber-reinforced geopolymer matrices was finally studied by SEM. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Eco-friendly additive construction: Analysis of the printability of earthen-based matrices stabilized with potato starch gel and sisal fibers(Elsevier Ltd, 2022-09-12)3D printing for construction purposes is a disruptive technology with the potential for rapid and massive applications making it a feasible alternative for social housing, temporary shelters after disasters, and, recently, for extraterrestrial habitats. However, most of the matrices used for construction by 3D printing are based on hydraulic cement as the main constituent, which is not easily available in remote locations and is an important greenhouse gases generator. Therefore, a good understanding to formulate and evaluate alternative matrices using soil and organic materials with the required fresh and hardened-state properties compatible with this emerging technology is needed. This article studies the printable capabilities of eco-friendly earthen-based matrices which uses potato starch as a natural stabilizer for raw soil mortars aiming to obtain 3D printed filaments with adequate fresh and hardened-states properties. The aqueous starch gel was combined with sisal fibers in the printing mixture to control shrinkage cracking problems during hardening. The optimization of the dosage of the stabilizer was carried out considering different tests in fresh and hardened printed filaments namely, pumpability and extrudability, stacking, shear vane, shrinkage cracking, Vicat needle, compression strength, and capillarity absorption tests. The results indicate that printable earthen-based matrices reinforced with 1 % of sisal fibers by weight of soil and stabilized with aqueous starch gels with concentrations up to 5 % (w/w) showed improved workability and minor cracking and can be used for 3D printing. These promising results in the field of material science combined with novel 3D printing technology that is also presented in the article open new lines of research for eco-friendly alternatives for the construction industry. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Additive construction of concrete deep beams using low-cost characterization methods and FEM-based topological optimization(Elsevier Ltd, 2024-03-08)Additive manufacturing using concrete for large-scale construction purposes has demonstrated economic, social, and environmental benefits compared to conventional building procedures. These advantages stem from the capabilities of concrete 3D printing, which facilitates a rapid, accurate, and low-waste construction process with substantially less labor and energy requirements compared to traditional casting procedures such as formwork fabrication and stripping, concrete pouring, and concrete consolidation. This technology can pave the way for sustainable and cost-effective housing solutions when coupled with low-carbon concrete formulations and optimized structural designs. However, scientific and industrial experiences have shown that formulating printable concrete requires extensive testing and costly equipment to reach appropriate fresh and hardened-state properties. Therefore, accessible and practical mix-design protocols for the evaluation of printable concrete formulation are needed to enable in-situ control and broader adoption of 3D printing. Once a printable material is developed, innovative design methods, such as topology optimization, that exploit robot-controlled construction to fabricate efficient, safe, and free-form elements can be explored. In this context, this article presents a methodology based on a set of low-cost and accessible experimental tests to develop cement-based matrices with low binder content suitable for layer-by-layer deposition. Furthermore, a framework to design and fabricate efficient structural elements based on numerical-based topological optimization and concrete additive manufacturing is proposed and validated. The systematic experimental campaign carried out indicates that the yield strength obtained from shear vane tests, initially designed for geotechnical field tests, is a reliable reference value for proportioning extrudable, pumpable, and buildable concretes. Employing the proposed framework, four formulations with excellent printing capabilities are presented. These formulations are successfully utilized for additive manufacturing of a topologically optimized deep beam, achieving a remarkable 52% mass reduction compared to a solid element. This showcases the possibility of 3D printing structurally efficient elements with intricate geometries while minimizing material usage, all without the need for formworks.Principio del formulario. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Soil-Cement Matrices for Additive Construction: 3D Printing System Validation and Printing Tests(Trans Tech Publications Ltd, 2023-01-01)Soil as a building material is gaining renewed interest from academia, and the constructionsector, mainly for fabricating low-environmental impact homes. The fabrication of houses with soilusing traditional methods such as adobe, cob, and rammed earth dates back to ancient times. However, emerging construction technologies, such as 3D printing, can be compatible with this material for building purposes. The article presents the validation of a 3D printing system for construction applications and the evaluation of soil-cement matrices' printability. First, the paper defines the printing parameters through experimental testing on soil matrices. Then, the article evaluates the printability of soil-cement matrices through filament printing and stacking tests. The results show that the 3D printing system prototype can fabricate small and medium-sized elements with soil matrices after correctly defining the pumping speed, printing speed, and layer height. Furthermore, experimental printing test results demonstrate that soil-cement matrices can be easily extruded and stacked; however, their printability capacity is strongly affected by the total water content and printing speed. This research highlights the suitability of soil-cement mixtures for additive manufacturing, a promising outcome that can facilitate the construction of homes in remote areas using 3D printing systems. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Preliminary Experimental Evaluation of Buildability Improvement Methods for Concrete for 3D Printing(Trans Tech Publications Ltd, 2023-01-01)3D concrete printing is an innovative construction process based on fully auto nomousmaterial deposition. One of the challenges of implementing this technology is the development of printable concrete formulations, as this material must exhibit particular fresh-state properties. Among these, buildability is one of the most important. This property describes the material's ability to support weight at very early ages, allowing a layer-by-layer construction. Therefore, this paper aims to evaluate two approaches for improving concrete buildability: the optimization of the super plasticizer dosage and the external application of quick-setting admixture. The results showed that reducing super plasticizer content improved buildability by increasing the static yield strength.However, this approach has a collateral disadvantage as concretes presented problems duringextrusion. On the other hand, the results of cylinder stability and Vicat tests indicate that the external application of quick-setting admixture leads to concretes with improved buildability without affecting the initial workability and a faster hardening process. According to these results, the latter approachcan potentially be applied in small and large-scale 3D printing. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Non-Destructive Testing and Historic Building Information Modelling for the Structural Diagnosis of the Church of the Society of Jesus in Cusco, Peru(Inderscience Publishers, 2023-12-03)This paper aims at presenting the results of a set of non-destructive tests (NDT) applied to an emblematic stone masonry church and the generation of a 3D parametric model to store and visualise structural diagnosis information following the historic building information modelling (HBIM) framework. Reverse engineering techniques were applied to obtain a precise point cloud of the church. NDT results exposed that the church currently presents several structural anomalies such as cracks, efflorescence, and moisture, among others. In addition, the mechanical characterisation showed that the masonry walls and pillars have an elasticity modulus within the expected range. Furthermore, with the application of operational modal analysis (OMA), it was possible to identify three modes of vibration of the structure. The representation of all the non-geometric information inside the HBIM model plus the generation of a custom plugin allowed the visualisation and adequately managing of the structural diagnosis information of the project. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Evaluation of Chitosan and Potato Starch as Stabilizers to Improve the Mechanical and Water Durability Properties of Printable Earth-Based Matrices Reinforced with Sisal Fibers(Trans Tech Publications Ltd, 2023-01-01)Due to economic, sustainable, and aesthetic benefits, academia and the construction industry are exploring the use of earth in modern construction is being widely studied. Unfortunately, earth as a construction material has low mechanical, poor water durability resistance, and the potential to swell and crack. Therefore, this paper evaluates chitosan and potato starch, natural biodegradable polymers, as stabilizers to improve mechanical strength and water durability resistance of printable earth-based matrix reinforced with sisal fibers. Although the test results indicated that the chitosan had a better performance as an earth stabilizer than potato starch, adding both stabilizers resulted in earthen composites with higher compressive strength and lower water permeability. These results demonstrate the feasibility of using natural stabilizers to improve the performance of earth-based materials for 3D printing without affecting their printability capacities.