• Energy Research
• civil engineering close
• 12. Responsible consumption close
• 6. Clean water close

[EN] The recently established Sustainable Development Goals recognize the importance of infrastructures for achieving a sustainable future. Along their long-lasting life cycle, infrastructures generate a series of impacts, the reduction of which has been one of the main focus of researchers¿ attention in the past years. The optimization of maintenance intervals of structures, such as bridges, has aroused the attention of the civil engineering sector, since most of the impacts of infrastructures occur during the operational phase. Thus, bridges are currently designed to attend the economic and environmental impacts derived from maintenance activities. However, the social pillar of sustainability is usually neglected in those analyses. Since no universally accepted methodology does yet exist for its consistent evaluation, the social dimension is not effectively included in the life cycle assessments of infrastructures. This communication evaluates the life cycle impacts of alternative concrete bridge deck designs in a maintenance-demanding environment near shore. Reliability-derived maintenance intervals are first optimized by minimizing the economic and environmental impacts. In a second stage of the analysis, the social dimension is included in the optimization process and results are compared. Optimization results from these combined assessments are obtained applying the Multi-Criteria Decision-Making technique AHP-TOPSIS. The present paper demonstrates how the inclusion of the social dimension may lead to different, more sustainability-oriented optimal maintenance strategies. The three-dimensional approach applied here has resulted in other alternatives to be preferred against those derived from the conventional assessment that considers the economic and environmental perspectives. Such finding supports the idea that holistic life cycle assessments are required for sustainable designs of infrastructures and that more efforts are urgently needed to integrate the social dimension in sustainability assessments of structures. The authors acknowledge the financial support of the Spanish Ministry of Economy and Competitiveness, along with FEDER funding (Project: BIA2017-85098-R).

Abstract A renewable energy storage system is being proposed through a multi-disciplinary research project. This system utilizes reinforced concrete pile foundations to store renewable energy generated from solar panels attached to building structures. The renewable energy can be stored in the form of compressed air inside the pile foundation with a hollowed section. The pile foundation should resist complex combined actions including structural loads, soil effects, and pressures induced from the compressed air, and thus it requires a careful analysis and design considerations to secure a sufficient structural safety. This paper presents analytical investigation results on the structural responses of the energy piles under these combined loadings. The pile foundations were designed based on the current design practices for various building geometries including the number of stories and column spacing. The magnitude of air pressure was determined from the thermodynamic cycles for the available renewable energy for storage considering building and pile foundation geometries. Finite element analyses were conducted using an elastic 3D model to determine critical tensile stresses of the pile foundation. These critical tensile stresses were used to identify required reinforcement in the pile section. On this basis, several nonlinear finite element analyses were then conducted using inelastic constitutive models of materials to investigate the crack patterns of the hollowed concrete section. Recommendations were finally presented for proper practical designs of the pile foundation serving as the renewable energy storage medium.

The need to lower the embodied carbon impact of the built environment and sequester carbon over the life of buildings has spurred the growth of mass timber building construction, leading to the introduction of new building types (Types IV-A, B, and C) in the 2021 International Building Code (IBC). The achievement of sustainability goals has been hindered by the perceived first cost assessment of mass timber systems. Optimizing cost is an urgent prerequisite to embodied carbon reduction. Due to a high level of prefabrication and reduction in field labor, the mass timber material volume constitutes a larger portion of total project cost when compared to buildings with traditional materials. In this study, the dollar cost, carbon emitted, and carbon sequestered of mass timber beam–column gravity system solutions with different design configurations was studied. Design parameters studied in this sensitivity analysis included viable building types, column grid dimension, and building height. A scenario study was conducted to estimate the economic viability of tall wood buildings with respect to land costs. It is concluded that, while Type III building designations are the most economical for lower building heights, the newly introduced Type IV subcategories remain competitive for taller structures while providing a potentially significant embodied carbon benefit.

Concrete is a worldwide construction material, but it has inherent faults, such as a low tensile strength, when not reinforced with steel or other forms of reinforcement. Various innovative materials are being incorporated into concrete to minimise its drawbacks while concurrently improving its dependability and sustainability. This study addresses the research gap by exploring and enhancing the utilisation of glass fibre (GF) concerning its mechanical properties and reduction of embodied carbon. The most significant advantage of incorporating GF into concrete is its capacity to reduce the obstruction ratio, forming clusters, and subsequent material solidification. The study involved experiments wherein GF was incorporated into concrete in varying proportions of 0%, 0.5%, 0.75%, 1%, 1.25%, 1.50%, 1.75%, and 2% by weight. Mechanical tests and tests for durability were conducted, and Embodied carbon (EC) with eco-strength efficiency was also evaluated to assess the material’s sustainability. The investigation found that the optimal percentage of GF to be used in concrete is 1.25% by weight, which gives the optimum results for concrete’s mechanical strength and UPV. Adding 1.25% GF to the material results in increases of 11.76%, 17.63%, 17.73%, 5.72%, and 62.5% in C.S, STS, F.S, MoE, and impact energy, respectively. Concrete blended with 1.25% of GF has the optimum value of UPV. The carbon footprint associated with concrete positively correlates with the proportion of GF in its composition. The optimisation of GF in concrete is carried out by utilising the response surface methodology (RSM); equations generated through RSM enable the computation of the effects of incorporating GF in concrete.

Concrete is one of the most used materials after water. Largely owing to this, its environmental impact is substantial, although its embodied carbon per unit volume or mass is low when compared to most alternatives. This, along with the broad availability, good strength, durability and versatility of concrete means that it will remain a material of choice, although more efficient ways of using it must be found. Structurally optimized building components are a means to do this as they can save about 50% material. Unfortunately, however, such elements are presently too expensive to produce owing to them requiring non-standard formwork. It is an objective of digital fabrication to propose solutions to this issue. In this con-text, Digital Casting Systems (DCS) have advanced material control strategies for setting-on-demand in digital concrete processing. Thereby, the formwork pressure is reduced to a minimum, which opens possibilities of rethinking formworks as systems that are dynamically shaping, millimetre thin or weakly supporting the material cast inside. In this paper we present a brief overview of millimetre thin formworks and summarize the first realization of concrete elements that utilizes the mechanics of paper folding to make millimetre thin formworks up to 2.5 meters high. Such formworks could initially be flat packed, erected into shape, and eventually peeled-off and recycled in established material streams. This would reduce waste and transport cost, while offering a surface finish that meets the expectations for exposed concrete surfaces.

The rational use of natural resources and the creation of an environmentally safety is a priority goal for all mankind. The increasing pollution of the atmospheric air by the combustion products of various types of fuel actualizes the problem of improving the environmental safety and efficiency of heat supply systems (HSS). Heating is the most energy intensive and wasteful sector of the national economy, because the turnover is comparable to 2.1% of GDP and an average of 50% in payment of citizens for housing and communal utility services (HCUS). However, HSS today is in a critical state at all stages of production, distribution and consumption of heat, which is especially typical for HCUS enterprises in Russia. Accordingly, the population is not satisfied with the quality and price of HCUS services. The purpose of the study was to develop a mechanism for creating an environmentally safe and reliable HSS by introducing energy-saving technologies that can improve the quality and reduce the price of HCUS services. The data analysis of the online survey of Russians in social networks in 2018-2019 is carried out. The average level of the population satisfaction with the quality of the provided services of HSS is determined.

The production process of the traditional paper making process produces a large amount of waste water, known as paper black liquor. It is needed to explore new ways of reusing this waste and replacing part of the base bitumen to reduce the consumption of non-renewable resources, such as petroleum, thus obtaining better environmental, economic, and social benefits. This paper analyses the feasibility of using paper black liquor, which contains a large amount of lignin, as a modifier for bitumen in the paper industry. Samples of modified bitumen were prepared with 15%, 30%, and 45% of the base bitumen replaced by paper black liquor, and a control group of base bitumen was prepared for testing. The samples were subjected to an 85 min short-term ageing test, FTIR scanning test, thermogravimetric test, frequency scanning test, MSCR test, and LAS test. The analysis of the FTIR and thermogravimetric tests showed that the paper black liquor was mainly composed of lignin and some cellulose, and contained a small amount of salts with Na ions; based on the results of the frequency scan, the compatibility analysis of the vGP curve showed that the modified bitumen was more compatible in the high-temperature range after short-term ageing, thus inferring that the water content of the concentrate had an influence on the compatibility, making it necessary to further investigate different optimum water contents to achieve the best performance and benefit. The incorporation of paper black liquor improved the rutting resistance and fatigue resistance of the modified bitumen, and also gave the paper-black-liquor-modified bitumen a better ageing resistance than the base bitumen. While demonstrating the feasibility of using paper black liquor as an bitumen modifier, this study also helps to provide a basis for theoretical applications of biomass materials in the field of road engineering.

Given the increasing global concern of freshwater scarcity, the use of seawater in concrete mixtures appears to be a way forward towards achieving sustainable concrete, especially in the case of non-reinforced concrete applications or with the use of non-corrosive reinforcement. This paper reports on the results of an experimental study to compare the freshwater-and seawater-mixed concretes in terms of their strength, shrinkage and permeability performance. The experimental program included the following: (i) compressive strength test (at 3, 7, 28, and 56-day ages); (ii) concrete shrinkage test (at Days 4, 7, 14, 21, 28, and 56 following mixing); and (iii) permeability tests (rapid chloride permeability and water absorption at Days 28 and 56 following mixing). As for the study results, seawater concrete showed a slightly higher early-age (i.e., till Day 7) strength performance than that of freshwater-mixed counterpart, followed by a strength performance that is 7–10% inferior to the freshwater concrete after 28 days or later. Also, the shrinkage of seawater concrete was slightly higher than that of freshwater concrete, with a difference of 5% reported after 56 days following mixing. Finally, the permeability performance of hardened concrete in seawater and freshwater mixtures was similar.