Carbon footprint is one of the most widely used tools for assessing the environmental impacts of the production and utilization of concrete as well as of the components derived from it, representing the amount of carbon dioxide and other greenhouse gases associated with this product, expressed as CO₂ equivalents. In this paper, carbon footprint was used to compare the environmental performance in the production phase of a concrete made with both recycled and crushed virgin limestone aggregates, using a life cycle analysis methodological approach. Research outcomes revealed, as expected, that carbon dioxide equivalent emissions decreased slightly as the use of recycled aggregates increased. Emissions for concrete with 0.5 w/c were between 347 and 351 kg of CO₂‐e/m³. It was also corroborated that cement is the material with the greatest influence on greenhouse gas emission generation in the concrete’s production phase, regardless of the use of recycled or virgin aggregates.

In this research, the effect of the addition of zirconium oxide-synthesized nanoparticles on the microstructural development and the physical–mechanical properties of cement mortars with limestone aggregates was studied. Zirconia nanoparticles were synthesized using the co-precipitation method. According to XRD analysis, a mixture of tetragonal (t) and monoclinic (m) zirconia phases was obtained, with average crystallite sizes around 15.18 and 17.79 nm, respectively. Based on the ASTM standards, a mixture design was obtained for a coating mortar with a final sand/cement ratio of 1:2.78 and a water/cement ratio of 0.58. Control mortars and mortars with ZrO₂ additions were analyzed for two stages of curing of the mortar—7 and 28 days. According to SEM analysis, mortars with ZrO₂ revealed a microstructure with a high compaction degree and an increase in compressive strength of 9% on the control mortars. Due to the aggregates’ characteristics, adherence with the cement paste in the interface zone was increased. It is suggested that the reinforcing effect of ZrO₂ on the mortars was caused by the effect of nucleation sites in the main phase C–S–H and the inhibition of the growth of large CH crystals, and the filler effect generated by the nanometric size of the particles. This produced a greater compaction volume, suggesting that faults are probably originated in the aggregates.

In this study, the photocatalytic activity of coating mortars with synthetized and commercial TiO₂ nanoparticles added has been evaluated at 2, 3 and 5% by weight of cement by calculating the degradation efficiency of methyl orange and red wine dyes exposed to both visible-light and UV radiation; also, the self-cleaning effect of coatings exposed to weather conditions (warm sub-humid climate) was assessed. TiO₂ nanoparticles were synthesized via the sol–gel method to a low synthesis temperature and characterized via X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The results show synthesized TiO₂ particles in anatase phase with a crystallite size of 14.69 nm, and hemispherical particles with sizes of submicron order. The addition percentage with the best performance in the coating mortars was 3%, with both commercial and synthesized TiO₂; however, coating mortars with synthesized TiO₂ exhibited the highest degradation efficiency for both dyes when they were exposed to visible light, while mortars with commercial TiO₂ exhibited the highest degradation efficiency when exposed to UV radiation. In addition, in coating mortars with synthesized TiO₂, the self-cleaning effect was evident from the beginning of exposure to weather, reaching the largest dye-free surface at the end of exposure. The compressive strength increased significantly in mortars with TiO₂ addition.

This work presents a bibliometric study of the literature on the use of caucho in the construction to promote the interest of using rubber as a prime material to reduce pollution at a global level. Published papers in the period 1999-2020 in both databases, Scopus and Web of Science (WoS), are taken into account using the Methodi Ordinatio and the VOSviewer software. A total of 967 documents on the use of rubber in structural and non-structural concrete have been published in this period and 1182 authors have contributed on the subject. Since 2010, the interest of researchers in introducing rubber in construction has increased. China, USA and Australia are the countries with the greatest interest in investigating about rubber-concrete.

Sustainability of cities and the environmental implications of high resource utilization by the domestic sector are growing concerns related to urban regions. Well-informed urban planning decision-making is an essential tool to help in the task and, for that, an important point to consider is the influence of parameters like residential density and housing typology on the intensity of resource utilization. Emergy synthesis, a life-cycle energy analysis methodological approach that considers the interaction of natural and human-made flows, was used to evaluate the environmental support for dwelling operational stage in five typical present-day housing units on the island of Montreal. As expected, resource utilization, measured as total emergy used, was positively correlated to housing unit size both with respect to number of occupants and dwelling size. Results suggest that variables affecting notably the intensity of resource utilization are per household income and per dweller habitable space and, while a higher income increased per capita emergy in all cases, increasing space availability per resident did not result in a decrease of empower density after 50 m²/person. Future work should consider lower and higher densities and analyses at the scale of blocks, neighborhoods and urban planning zones.