Concrete is the most-used material in the construction industry, and the second most-used after water. Cement is the main component of concrete. A total of 8% of global CO₂ emissions correspond to the cement industry; CO₂ is the main greenhouse gas contributing to global warming. To mitigate climate change, it is necessary to design buildings with a lower environmental impact, and therefore, it is crucial to assess the environmental profile of the local production of construction materials. This study uses the life cycle assessment methodological framework to evaluate the environmental sustainability of the cement and concrete industry in Ecuador. The inventory accounts for 62.8% of national cement production, with data corresponding to 2019. The OpenLCA software was used to perform the life cycle inventory and impact assessment calculations. Eight impact categories were assessed, including Global Warming Potential (GWP). Clinker has a GWP result of 897.04 kg CO₂-Eq/ton. Hydraulic cement types MH, GU, and HE have GWPs ranging from 465.89 to 696.81 kg CO₂-Eq/ton. Results of ready-mixed concrete range from 126.02 to 442.14 kg CO₂-Eq/m³. Reducing the content of clinker in cement and concrete should be the aim so as to improve their environmental profiles. This study contributes to the development of regional life cycle inventory data for Latin America. This research is the first to be developed regarding construction materials in Ecuador and contributes to the sustainable design of structures with pozzolan-lime cement and concrete.

The use of Supplementary Cementitious Materials (SCMs) or industrial wastes as a partial replacement for cement in the production of concrete is an urgent need in the construction industry due to cement's growing environmental challenges and rising cost. In respect of this, we conducted research work on proportioning binary concrete mixes. Fly ash (FA) replaced 10 %, 20 %, and 30 % of the cement, while silica fume (SF) replaced 5 %, 10 %, and 15 % of the cement. A control concrete mix was also developed with 100 % cement and no SCM. The results showed no increase in compressive strength for FA concrete compared to control at the early age of 3–28 days, but a maximum increase in compressive strength of 4 % was discovered at a later age of 56 days for concrete with 20 % FA. For 5 % SF concrete, a considerable strength increase of 15 % was seen at the early age of 3 days. Like with FA concrete, 2 % improvement in strength was recorded at the later age of 56 days for 10 % SF concrete. This study further focused on the concrete's temporal evolution of compressive strength by developing a strength evolution model (SEM) using nonlinear regression analysis at a 95 % confidence level. Pearson correlation coefficient was used to determine the correlation between the model values and the experimental results. For comparison, the fib Model Code 2010 was applied to the experimental data, and a good agreement was observed among the proposed model, the fib Model values, and the experimental results. The proposed model can be expanded to address further regression-related problems. Finally, environmental life cycle assessment revealed that utilizing 10 %, 20 %, and 30 % of FA lowered Global Warming Potential (GWP) by 9 %, 19 %, and 29 %, respectively. Likewise, using 5 %, 10 %, and 15 % of SF reduced the GWP by 5 %, 9 %, and 14 %.

Circular economy (CE) describes a sustainable alternative approach to the current linear economy system. It is a growing topic among scholars, practitioners, and decisionmakers; it encompasses several concepts related to sustainability and requires the synergy of multiple actors for success, including higher education institutions (HEIs) as one of the most relevant ones. Current CE is based mostly on experiences in Global North developed countries, where the concept has gained great attention and has already influenced policies and strategies. However, CE in Latin American countries (LA countries) have not yet received such attention. Thus, some “unique problems” may remain unattended, and efforts to attain a CE are more likely to fail. Likewise, the study shows how the role of HEIs in CE in LA countries has not yet been fully explored, as the literature on this topic is scarce. This paper aims to address the main research question: what is the role of HEIs in the transition to a CE in Latin American countries? For this, a two-fold methodology was performed: (i) a systematic review which allows understanding of the trends of CE research in LA and the extent of the HEIs involvement; and (ii) a narrative review, which provides insights into the state of the art of CE research (gaps, drivers, and barriers) in LA countries and how this relates to HEIs. This approach drew implications for the role of HEIs in the implementation of CE in LA countries. HEIs are key actors in this transition, contributing in several ways to the CE by collaborating with industry, assisting policy makers, building human and intellectual capital, supporting community engagement projects, influencing campus culture, linking with international CE networks, and promoting an inclusive CE discourse. This research contributes to the CE body of knowledge from a Latin-American Global South perspective by discussing the factors that aim to define the role of HEIs in the CE transition in LA countries.

In recent years, several researchers have studied the potential use of ammonia (NH₃) as an energy vector, focused on the techno-economic advantages and challenges for full global deployment. The use of ammonia as fuel is seen as a strategy to support decarbonization; however, to confirm the sustainability of the shift to ammonia as fuel in thermal engines, a study of the environmental profile is needed. This paper aims to assess the environmental life cycle impacts of ammonia-based electricity generated in a combined heat and power cycle for different ammonia production pathways. A cradle-to-gate assessment was developed for both ammonia production and ammonia-based electricity generation. The results show that electrolysis-based ammonia from renewable and nuclear energy have a better profile in terms of global warming potential (0.09–0.70 t CO₂-eq/t NH₃), fossil depletion potential (3.62–213.56 kg oil-eq/t NH₃), and ozone depletion potential (0.001–0.082 g CFC-11-eq/t NH₃). In addition, surplus heat for district or industrial applications offsets some of the environmental burden, such as a more than 29% reduction in carbon footprint. In general, ammonia-based combined heat and power production presents a favorable environmental profile, for example, the carbon footprint ranges from −0.480 to 0.003 kg CO₂-eq/kWh.