Javier Rodrigo Nahuat-Sansores

Population growth, high ambient temperatures, and longer warm periods have led to increased energy consumption related to heating and cooling systems. The building envelope plays a fundamental role in the performance of such systems to reduce heat transfer into buildings. This study evaluated the effect of incorporating phase change materials (PCMs), namely Glauber’s salt and calcium chloride hexahydrate, into a cement-based mortar. The PCMs were impregnated into basalt aggregate used as a supporting medium and encapsulated. The physicochemical, mechanical, and thermal properties of the mortars were characterized before and after PCM incorporation. The mortars with PCMs exhibited reductions in thermal conductivity of 48% and 53%, thermal diffusivity of 40% and 45%, and volumetric heat capacity of 17% and 24%, respectively, as determined according to ASTM D5334. Thermal performance was evaluated using hot-box equipment, demonstrating a reduction in the temperature fluctuation of up to 2.865 °C and average reductions in maximum temperature peaks of 0.3106 °C. Compressive strength revealed reductions of 61% and 76% relative to the reference mortar for each modified mortar. PCM-modified mortars satisfied the minimum requirements established for non-structural rendering applications and exhibited a substantial improvement in overall thermal performance. These results suggest their potential use as passive coating materials for thermal management in buildings.

Sugarcane bagasse ash (SCBA) has been widely studied as a partial supplementary cementitious material; nonetheless, its hydration behavior and performance when combined with nanoscale modifiers remain insufficiently understood. The aim of this study is to assess the pozzolanic potential of SCBA, the hydration behavior of binary SCBA–cement composites and the mechanical performance of ternary mortars with silica nanoparticles (Si-NPs). SCBA reactivity was confirmed by a Chapelle index of ~300 mg Ca(OH)₂/g, while hydration development in binary pastes (5–20 wt% SCBA) was quantified using TG/dTG and semi-quantitative XRD. Low SCBA replacement levels (5–10 wt%) enhanced the hydration degree by up to ~12% at 28 days compared with the reference paste. Ternary mortars incorporating 5 wt% SCBA and Si-NPs exhibited significant strength gains, with the optimal blend (2.5 wt% Si-NPs) achieving a 42% increase in 28-day compressive strength relative to the reference mortar. A sustainability assessment showed concurrent reductions in clinker intensity and CO₂ intensity of approximately 33% and 32%, respectively. These findings support the sustainable and technical viability of combining agro-industrial waste and nanotechnology as complementary strategies for reducing clinker content while enhancing eco-efficiency in alternative cementitious composites.

Inorganic phase change materials (PCMs) can be employed in passive thermal regulation systems as building envelopes to decrease energy consumption. Nonetheless, they present a manifold of issues, such as leakage, incongruent melting, crystallization, and supercooling, which limit their performance and durability. A widely explored approach to address these shortcomings is the development of eutectic salts and their stabilization through techniques such as the use of porous substrates and encapsulation, in addition to combining them with the incorporation of carbon derivatives as fillers and nucleating agents to enhance thermal performance and durability during charge and discharge cycles. In this study, a critical review is developed via analysis and discussions of different methods for incorporating inorganic PCMs. The focus is mainly on eutectic salts and the challenges associated with their application, the generation of new eutectic salts, stabilization methods, and use cases where the incorporation of fillers, the use of porous substrates, and the implementation of nucleating agents have contributed to improving thermal performance, reducing the degree of supercooling, and minimizing PCM leakage during phase transitions.

An intricate relationship exists between the durability performance of reinforced concrete and the migration of chloride ions, particularly in marine and coastal environments. The aim of this work was to study the influence of ceramic waste (CW) as cement replacement on the chloride migration of limestone aggregate concrete, based upon rapid chloride migration testing through the non-steady-state migration coefficient according to NT build 492. The chloride penetration inhibitor potential of CW in concrete was assessed through physical and chemical analyses. Mortar and concrete samples with two different water/binder ratios (0.5 and 0.7) were designed. The cement replacement ratios were 10, 15 and 20% by weight. The focus of the study was on the transport properties (particle size distribution, density, absorption, capillarity, sorptivity, chloride migration coefficient) and mechanical properties (compressive strength, strength activity index), along with chemical and environmental (cement intensity index) characterisation of CW–cement concretes. The results showed a significant improvement in the chloride penetration resistance of the CW–cement concrete, even considering the selection of limestone aggregates. The concomitant pozzolanic/filler effect of CW particles provided further densification and refinement of the microstructure, leading to enhancements in the physical and mechanical properties, and thus in the eco-efficiency of the CW-blended concrete.

This research work is focused on the development of an alternative method for manufacturing Wood Plastic Composite (WPC) panels based on Wood Veneers (WVs) and High-Density Polyethylene (HDPE) through compression molding, which enhances the physical properties, particularly, water absorption and moisture content. The aim of the present research was to develop alternative panels to replace commercial ones, which are heavily affected by hot, humid climates. In this context, the study began with the design process, which consisted of the collection and processing of primary material, production of the additional components necessary for the manufacturing process, determination of the WV ratio, and preparation of the samples. Thereafter, physical and mechanical tests were carried out on WPC, HDPE (control), commercial gypsum boards (GBs), plywood (PW), and medium density fiberboard (MDF) samples. The results indicate that the method applied to manufacture the WPC samples improved physical properties, achieving a water uptake of less than 4% in both proportions of replacement tested, in contrast to commercial panels, which reached values between 10% and 40%. In addition, a greater load capacity was achieved for lower thick elements.

For decades, researchers on materials science have highlighted the potential of biochar as a CO2 adsorption medium and the possibility of its incorporation into other materials to reduce the overall carbon footprint. This present study is a critical review of a selection of articles about biochar potential as a material on the construction industry. Biochar is a promising material in order to mitigate GHG emissions when added to cementitious materials, reducing its carbon footprint through a dual effect: CO2 sorption and replacement of cement or aggregates. Literature evidenced that replacement ratios of around 2-8 of cement wt% improved or leveled with conventional cementitious composites. However, some recent studies have shown that the incorporation of biochar up to >10% replacement ratios have the potential to improve the composites. Based on this premise, the present review emphasizes on the durability and long-term properties of biochar cementitious composites by providing up-to-date discussions of the studies on the matter and the future perspectives of the research in order to develop more eco-efficient concretes or mortars.