DSpace-CRIS

Now showing 1 - 3 of 3

Some of the metrics are blocked by your
consent settings
Development and characterization of a printable concrete made with construction and demolition waste aggregates
(Springer Science and Business Media B.V., 2024-01-01)
To address the environmental challenges associated with Construction and Demolition Wastes (CDW) disposal and the depletion of natural sand resources by the construction industry, this paper investigates the potential use of fine aggregates from CDW as a complete replacement for natural sand in concrete formulations tailored for 3D printing applications. The study begins by physically characterizing fine aggregates produced by crushing and sieving CDW from concrete and fired clay brick residues. This stage includes water content and water absorption capacity tests, specific gravity tests and unit weight tests, and particle size analysis. Then, a 3D printable concrete mix formulated entirely with CDW fine aggregates, replacing 100% of natural sand, is developed using mortar flow and rotational rheology tests. This formulation is validated by printing a medium-sized wall using a 3D printing system developed in-house. Finally, compression tests are performed on printed filaments to examine mechanical properties such as compressive strength and modulus of elasticity. Fresh-state and hardened-state properties are compared with control concrete samples made with natural sand (0% of CDW fine aggregates). The study demonstrates the feasibility of formulating printable concretes with a total replacement of sand by CDW for real-size applications. However, special attention must be given in large-scale projects to the rate of workability loss caused by the high water absorption capacity of CDW fine aggregates. The research findings offer valuable insights into the potential and performance of CDW aggregates in 3D-printed concrete applications within the context of a circular economy.
Some of the metrics are blocked by your
consent settings
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.
1
Some of the metrics are blocked by your
consent settings
Effect of Peruvian sisal fiber on the mechanical and microstructural strength of concrete
(Springer Science+Business Media, 2025-06-01)
In response to environmental concerns, such as global warming, there has been growing interest in the development of sisal fiber (SF)-reinforced concrete due to its low environmental impact and reduced cost. This study evaluated the effect of SF on the mechanical and microstructural properties of concrete. Sisal fibers, with a length of 50 mm, were selected and added to concrete at 0.5, 1, 1.5, 1.5, and 2% by weight of cement, with a treatment using CaO for 7 days. A total of 80 specimens were prepared to analyze compressive strength, tensile strength, flexural strength, elastic modulus, and microstructural properties. The results showed that the optimum SF content was 1.5%, where parameters such as workability, unit weight, and air content decreased but remained within permissible ranges, while temperature remained constant. Significant improvements were observed in compressive, tensile, and flexural strengths, with increases of 17.80%, 52.30%, and 88.83%, respectively. However, a 5.56% reduction was observed in the elastic modulus compared to the reference concrete. X-ray diffraction analysis revealed changes in the concentrations of crystalline phases such as quartz and albite, while energy dispersive spectroscopy highlighted a higher oxygen content, indicating more efficient hydration of the cement. The 1.5% SF (T4) optimizes cost–benefit (+ 88.8%), but higher doses reduce efficiency. It is ideal for walls and sidewalks, prioritizing resistance to cracking and sustainability. SF is eco-efficient and economical compared to synthetic fibers. This demonstrates that the incorporation of SF into concrete represents a sustainable and efficient alternative that significantly improves its mechanical and microstructural properties.
4

Producción científica

Browse

Filters

Settings

Sort By

Results per page

Search Results