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The difficulty of decomposing solid waste over time has made it a significant global problem because of its environmental impact and the need for large areas for disposal. Among these residues is the waste of the rendering mortar that is produced (falls to the ground) while applied to wall surfaces. The quantity of these materials may reach 200 to 500 g/m2. As a result of local urban development (in Iraq), thousands of tons of these wastes are produced annually. On the other hand, the emission of greenhouse gases in the cement industry has had a great environmental impact. One of the solutions to this problem is to reduce the cement content in the mix by replacing it with less emissive materials. Residues from other industries are considered a relatively ideal option due to their disposal on the one hand and the reduction of harmful emissions of the cement industry on the other hand. Therefore, this research aims to reuse rendering mortar waste powder (RMWP) as a possible alternative to cement in mortar. RMWP replaced the cement in proportions (0, 10, 15, 20, 25, and 30% by weight). The flow rate, flexural and compressive strengths, ultrasonic pulse velocity, bulk density, dynamic modulus of elasticity, electrical resistivity, and water absorption tests of the produced mortar were executed. Microstructural analysis of the produced mortar was also investigated. Results indicated that, for sustainable development, an eco-friendly mortar can be made by replacing cement with RMWP at a rate of 15%, resulting in a 17% decrease in compressive strength while maintaining or improving durability properties. Moreover, the microstructure became denser and more homogeneous in the presence of RMWP.

Concrete has always been indispensable as a material for the engineering and construction of hydraulic structures (e [...]

AbstractSince the beginning of the 21st century, straw-bale buildings are reappearing in the world; however, their thermal performances were not thoroughly investigated up to now. The purpose of this study is to analyze thermal behavior and energy performance of a straw-bale building in Switzerland. Using Pleiades+Comfie Software, building designs have been studied to understand the best way to mitigate overheating risks due to the low heat capacity of straw. Thermal-dynamic results and Life Cycle Assessment conclude that straw bale buildings can be a sustainable alternative in the energy evolution of building construction, due to its low embodied energy and excellent thermal performance.

Abstract Rammed earth is a traditional construction technology that has proven to be sustainable. This paper explores further improvement of its multifunctional performance by increasing the strength, reducing moisture permeation and increasing the thermal resistance. Surface application of microbial cementation was found to increase the strength by 25%. The water permeability and erosion of the blocks also reduced by 24% and 62% respectively, due to surface application of microbial cementation. The thermal test showed that addition of crumb rubber resulted in a temperature difference of around 30 °C even after 6 h. However, the addition of crumb rubber also reduced the strength. This research demonstrates that significant improvement of overall performance of rammed earth materials can be achieved through various treatments. However, the overall performance requirements are specific to the engineering application and synergistic and antagonistic interactions must be considered to obtain an optimal performance.

Concrete is the most used construction material in the world. Consequently, the mass extraction of virgin materials required for concrete production causes major environmental impacts. With a focus on promoting sustainability, numerous research studies on incorporating waste materials to replace virgin substances in concrete were undertaken. Despite this vast volume of published literature, systematic research studies on these sustainable concrete mixes that inform various stakeholders on current research trends, future research directions, and marketability options products are seldom conducted. This paper presents a decade review on sustainable concrete with a focus on virgin materials being replaced with waste materials. It aims to inform researchers of current research trends and gaps in the research area of waste material use in concrete. The review also identifies key parameters that restrict the marketability of these sustainable concrete products. The three-step research methodology involves a bibliometric assessment, a key review of selected waste materials, and an interview with a panel of experts focusing on impediments towards the transition of sustainable concrete products into the industry market. Bibliometric assessment was based on 1465 research publications in which five key materials (plastic, glass, fly ash, slag) and construction and demolition waste were selected for the review. The interview was conducted with ten industry experts to discuss the industry limitations in the commercial establishment of materials. The review of existing knowledge and the findings on sustainable concrete presented in this paper provide directions for both research academics and industry stakeholders to systematically focus on sustainable concrete products that are market-ready.

The paper proposes a novel decision analysis framework and corresponding probabilistic systems representations allowing for the consistent and integral quantification of systems resilience and sustainability. This facilitates–to the knowledge of the authors, for the first time–that decisions relating to the governance of socio-ecologic-technical systems may be optimized with due consideration of their impacts at both local and short-term time scales as well as on global and long-term time scales. The resilience performance of the interlinked system is modeled through the formulation of resilience failure events which occur if one or more of the capacities of the interlinked system are exhausted. Sustainability failure is analogously introduced as the event that one or more of the Planetary Boundaries are exceeded. A principal example shows there is a trade-off between resilience, generation of benefits, consumption of materials, and emissions to the environment. Resilience provides benefits to society but at the same time imposes material consumption and emissions to the environment. Systems can, however, be designed such that resource consumption and associated environmental impacts are reduced and the resilience performance is increased simultaneously. The example further illustrates that social governance system failure may follow from inadequate design and governance of infrastructure.

Abstract Approximately 5%–7% of global Carbon Dioxide (CO2) emissions can be attributed to Ordinary Portland Cement (OPC), which has traditionally been used as the primary binder in concrete. Geopolymer concrete has been widely claimed to have lower global warming potential than OPC concrete, and this claim has formed the basis of many studies examining mix designs and mechanical properties of geopolymer concretes. A major limitation with the vast majority of existing studies is a lack of the direct quantification of the global warming potential of the materials developed. That is, the underlying assumption in the majority of these studies is that geopolymer concrete is more sustainable than OPC based concretes. The aim of this paper is to quantify the CO2 equivalent (CO2-eq) emissions associated with production of a large number of previously developed mix designs (1404 mix designs from 110 studies) including the impacts of curing, allocation and transportation and allowing for variation in energy grid source and the production of the activator solution. When considering the impact of transportation, a case study based on five major capital cities in Australia is presented and the critical transport distances at which the manufacture of geopolymers becomes more emissions intensive than conventional concrete is identified. The results show that the relative CO2-eq emissions of geopolymer and OPC based concretes of the same strength, are highly dependent on the system boundary for analysis, the type of allocation scenario and material transportation distances and mode, and further, that depending on these factors geopolymer concretes can either have significantly lower, or significantly higher CO2-eq emissions than OPC concretes of the same strength. It is expected that the findings of this work can aid in specifying the optimal concrete types for reducing CO2-eq emissions considering the intended use of the concrete.

In this modern technological era today, green materials are highly regarded as one of the most important elements when designing and conducting an environmentally sustainable construction project. The cement that is utilized in conventional concrete today is one of the culprits for the high levels of carbon dioxide generated, which is damaging to the environment. Many researchers have shown and suggested that cement substitution is a favorite technique for minimizing the generation of greenhouse gas (GHG) emissions as well as substituting unused raw materials with concrete. The concept of green concrete promotes sustainable development as it utilizes the least natural resources during production and mainly depends on recyclable waste materials as its main raw material. This paper displays the various designs of green concrete in developed countries by partially replacing cement with recyclable materials such as fly ash, demolished waste from construction sites, electronic waste, carpet fiber waste, palm oil fuel ash, and others. Green concrete endorses the innovative and sustainable use of waste aggregate and unconventional alternative materials to substitute cement within concrete. It is crucial to adopt the use of green concrete, especially in developed countries, as they have the capacity and financial strength to ensure adequate training, public awareness, further research and demonstration projects, as well as suitable standards to be applied to endorse the global application of green concrete in infrastructure projects.