Geopolymer mortars were produced from construction and demolition waste using a binary binder of recycled brick powder/recycled concrete powder (RBP/RCP = 70/30 wt%), activated with a hybrid alkaline solution (NaOH/Na₂SiO₃/KOH) and reinforced with sisal fibres at 0–2 wt%. Mechanical performance (compression and three-point bending) and microstructure–phase evolution (XRD, FTIR, SEM-EDS) were assessed after low-temperature curing. Sisal addition delivered a strength–toughness trade-off with a reproducible optimum at ~1.0–1.5 wt%; at 2.0 wt%, fibre clustering and connected porosity reduced the effective load-bearing section, penalising flexure more than compression. Microstructural evidence indicates coexistence and co-crosslinking of N-A-S-H and C-(A)-S-H gels—enabled by Ca from RCP—leading to matrix densification and improved fibre–matrix anchorage. Fractographic features (tortuous crack paths, bridging, and extensive pull-out at ~1.5 wt%) are consistent with an extended post-peak response and higher fracture work without compromising early-age strength. This study achieves the following: (i) it identifies a practical reinforcement window for sisal in RBP/RCP geopolymers, (ii) it links gel chemistry and interfacial phenomena to macroscopic behaviour, and (iii) it distils processing guidelines (gradual addition, workability control, gentle deaeration, and constant A/S) that support reproducibility. These outcomes provide a replicable, low-embodied-CO₂ route to fibre-reinforced geopolymer mortars derived from CDW for non-structural and semi-structural applications where flexural performance and post-peak behaviour are critical.

The literature to date has not reported a clear consensus on the optimal length of fiberglass posts for efficient clinical performance when restoring endodontically treated maxillary incisors with severe crown destruction. This study aimed to determine the stress distribution of fiberglass posts at different lengths using finite element analysis. Five 3D finite element models (groups A-E) were created, each representing a restoration system for endodontically treated maxillary central incisors. The models included post-core crowns with crown-root ratios of 1/3, 1/2, 2/3, 4/5, and 1/1. A static load of 100N force was applied to the palatal surface at 45º to the long axis of the tooth. Von Mises values and | maximum stresses in the crown, dentin, resin cement, and post-core were evaluated separately. The maximum stress experienced was A < C < B < E < D. Von Mises stresses were located in the upper and middle buccal thirds and in the apical palatal third of post A, as well as the upper and middle buccal thirds in posts B, C, D, and E. The lowest distribution of maximum and Von Mises stresses was observed in model A.

Caracterización mecánica, físico-química de fibra de Sansevieria trifasciata, como posible refuerzo en un compuesto de matriz poliéster

The present research work had as study variables the current density of 20, 40 and 80 mA/cm² and residence times of 10, 20, 40 and 60 minutes, within these evaluation parameters values were taken of pH, conductivity and Fe²⁺ removal percentage before and after the electrocoagulation process of artisanal acid mine drainage samples (AMD), the amount of AMD sample per test was 350 mL per test, from the results obtained it could be observed that For the current density of 80 mA/cm² and a time of 40 minutes, the highest percentage of removal was obtained (76.20%), likewise a minimum percentage of removal of 17.97% was obtained at 20 mA/cm²; The removal percentages are attributed to the effect of the current density of the electrocoagulation process, which allows increasing the initial pH values of the effluent, which in turn allows the formation of precipitates and co-precipitates, in this case of Fe^2+.