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This is an investigation into asphalt binder mixed with different amounts of an organic waste containing coconut coir dust and residual short coconut fibers abundant in the Caribbean and tropical countries. The concentrations used were 0.0, 1.0, 2.5 and 5.0wt%. Coconut coir is a type of organic waste produced in large quantities in Caribbean region of Colombia. It is composed of grinded mesocarp, which is the fibrous husk of the coconut fruit, and is currently used in agriculture, ornaments and crafts. This waste is a very stable and strong material suitable for use in structural applications such as the reinforcement of composite materials. In this investigation, materials characterization was conducted using Fourier transform infrared spectroscopy and scanning electron microscopy to analyze the microstructure of samples. Particle size distribution tests were also included to analyze the short coconut fibers. Penetration, softening point, penetration index, viscosity, flash point, fire point and ductility performance tests were also carried out on the asphalt mixes. Overall, these tests revealed that asphalt formulations can be used in selected construction and building material applications.

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Metallic nanofoams, cellular structures consisting of interlinked thin nanowires and empty pores, create low density, high surface area materials. These structures can suffer from macroscopically brittle behavior. In this work, we present a multiscale approach to study and explain the mechanical behavior of metallic nanofoams obtained by an electrospinning method. In this multiscale approach, atomistic simulations were first used to obtain the yield surfaces of different metallic nanofoam cell structures. Then, a continuum plasticity model using finite elements was used to predict the alloy nanofoam's overall strength in compression. The manufactured metallic nanofoams were produced by electrospinning a polymeric non-woven fabric containing metal precursors for alloys of copper-nickel and then thermally processing the fabric to create alloy metallic nanofoams. The nanofoams were tested with nanoindentation. The experimental results suggest that the addition of nickel increases the hardening of the nanofoams. The multiscale simulation modeling results agreed qualitatively with the experiments by suggesting that the addition of the alloying can be beneficial to the hardening behavior of the metallic nanofoams, and helps to isolate the effects of alloying from morphological changes in the foam. This behavior was related to the addition of solute atoms that prevent the free dislocation movement and increase the strength of the structure.

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Earth architecture has been an ecological alternative since the surrounding materials can be used. The durability of earth elements such as compressed-earth blocks (a soil brick) is less than that of traditional blocks. In the present work, the evaluation of weathered earth-based walls was carried out after six years in the mid-region of the Gulf of Mexico coast (Tampico, Tamaulipas, Mexico) and contrasted with sections of compressed earth block without environmental degradation. The blocks were fabricated from two different blends with the following materials: (A) 50.4% clay soil (Altamira, Tamaulipas, Mexico), 38.4% Medrano sand, 6.4% cement, and 4.8% nopal mucilage aqueous solution (1:10). (B) 50% clay soil, 35% cement, 10% lime, and 5% nopal mucilage aqueous solution. A stochastic model was developed from image analysis to understand the biofilm formation process, and the modification of the compressive strength was evaluated. It was found that the compressive strength decreases (up to 65%) due to degradation. The CEBs stabilized with lime showed no surface changes, and there were no changes in the strength properties. For the cases in which there was degradation, it the fractal dimension and the respective specific surface area were found to have increased. This work can improve the perception of using this material in Mexico's regions, where the humidity levels are potentially dangerous for the earthen structures. Besides, it offers a non-destructive methodology to determine the deterioration of housing walls built with earth elements.