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Abstract The reuse of mining waste-rocks as construction material constitutes an innovative management approach consistent with the principles of sustainable development. Nevertheless, the implementation of this approach is still limited by most guidelines due principally to insufficient knowledge of these materials performances and to unjustified presumptions related to their chemical instability (presence of sulfide). This paper approaches these issues by assessing the reuse potential of low-sulfide mining waste-rocks as aggregates for concrete regarding to the Quebec (Canada) recycling guidelines of non-hazardous inorganic wastes as construction materials. Toxicity characteristic leaching procedure (TCLP), comprehensive physical, chemical (XRF and ICP-AES) and mineralogical investigations (XRD and SEM) as well as modern automated mineral liberation analyses have been carried out. In addition, UCS results of various concrete mixtures using different binders were then presented to illustrate the reuse potential of the waste-rocks. The TCLP test showed the nonhazardous character of the waste rocks. They contained low sulfide content (0.5 wt%), which classify them as non-acid generating and able to meet the classification in recycling category including concrete production. Moreover, liberation analyses showed that most sulfides are concentrated in the fine fraction as pyrite occurrence with a liberated fraction of only 2%. These results influenced significantly the properties of the resulting concretes, which presented good mechanical performances especially when coarse waste rock above 20 mm and fine one below 80 μm was removed. Highlights • TCLP test showed that waste rocks is a non-hazardous material. • Grain size distribution of coarse waste rocks fraction was similar to reference gravels used for concretes production. • Total sulfur content of waste rocks was not exceeding 0.5 wt%, classifying the material as non-acid generating. • Iron sulfides (mainly of pyrite) are almost encapsuled within gangue mineral. Only 2% of pyrite is free. • Natural sand instead of the waste rocks fine fraction improve the concrete strength. [ABSTRACT FROM AUTHOR]

The growing demand of construction around the world has led to the increased usage of concrete. However, conventional concrete-making materials are not entirely environmental-friendly and this has enthused research on seeking greener alternative for concrete production. In the past, extensive research works had been carried out to utilize farming waste materials such as those from palm oil, coconut, sugarcane as well as the paddy industry and these findings indicate potential of utilizing such materials in concrete. The re-use of the farming waste materials in concrete could reduce the dependency on conventional concrete-making material as well as minimizing the negative impact on the environment besides ensuring waste conservation and reduction in waste disposal from these sectors. In this paper, a review on the utilization of emerging alternative farming waste materials in concrete such as from the farming of bamboo, corn, wheat, olive, sisal, seashells and more is carried out with the aim of examining the benefits and shortcomings of using these materials. This review shows the possible usage of farming waste materials in different form in concrete, such as partial cement and aggregate replacement, as well as fibre reinforcement. The main finding from the paper is that although usage of farming waste materials resulted in lowering of some concrete properties, appropriate treatment methods and selection of the waste materials would enable the production of concrete with improved performance. The summary and discussion provided in this paper should provide new information and knowledge on a greater variety of farming waste materials which are suitable to be used for the production of a greener and sustainable concrete. [ABSTRACT FROM AUTHOR]

Waste from Electric and Electronic Equipment is one of the most rapidly developing waste streams worldwide. The aim of this paper is to investigate and evaluate the reuse methods of glass derived from electric lamp recycling. A detailed record of the various reuse methods of recycled glass is given, focusing on the use of glass in concrete industry, ceramic building materials and asphalt. Also, the necessary prerequisites, in order to produce final products within specifications, are highlighted for each case. The glass-cullet used in the research was produced in Oikokiklios S.A. lamp recycling company, where lamps are collected for recycling from all over Greece. Moreover, in order to investigate each case study, production data of three different companies (asphalt, cement, bricks) within close distance from Oikokiklios S.A. were used. As a result, three scenarios were studied in order to describe the glass-cullet reuse options and examine the benefits of introducing glass in each production process. More precisely, each scenario was evaluated concerning energy, environment and economic impact. The main conclusion of the research was that introducing glass is beneficial for all the above production processes leading to an important reduction of the released carbon dioxide emissions and energy consumption. [ABSTRACT FROM AUTHOR]

Phosphogypsum (PG) is a by-product from the industry of phosphate fertilizer. Approximately 4–6 tonnes of PG are generated per tonne of phosphoric acid production. The continuous growth in the world population increases food production demand which requires an increase in phosphate fertilizer production resulting in an increase in PG content. Approximately 85% of this by-product is still discarded into the ocean or river, or stored in ponds or leaps without purification. This disposal causes serious contamination. Reduction in the disposal of this by-product has economic and environmental benefits. Extensive investigations have been carried out to reuse PG in different fields such as soil stabilization amendments, agricultural fertilizers, set controller in cement manufactures and building materials. This paper reviews the earlier studies which reused PG as a construction material. The effect of PG on some properties of the matrix such as workability, unit weight, mechanical strength and durability has been reviewed and discussed. The outcome of this review should place a base for the future investigations and uses of PG in sustainable methods. [ABSTRACT FROM AUTHOR]

The issue of the ever increasing demand for construction materials and waste management has created a need for the development of sustainable materials with the appropriate utilization of wastes. This paper presents the study of the use of bio-briquette ash (BBA) for the development of bricks. Physico-chemical property investigations for a BBA sample were conducted, and the sample was found to be suitable as an alternative raw material for the partial substitution of sand. For the development of the bricks, BBA was added according to the partial replacement method (5–55%) for sand, keeping the cement percentage constant. Six compositions were prepared with 10 wt% variations. The developed product was tested according to the Indian Standards (IS) for density, compressive strength, water absorption and efflorescence along with the durability and thermal properties. The effect of the addition of the BBA on the brick properties was investigated. Thirty-five weight percent BBA, 55 wt% sand and 10 wt% cement were the optimal mix composition for the developed BBA bricks that fulfilled the desired properties of IS. The developed BBA bricks were found to have better mechanical and thermal properties and were more economical than commercially available fly ash and clay bricks. The developed bricks are recommended for non-load bearing walls. [ABSTRACT FROM AUTHOR]

The 21 s t century globalization and growth are being accompanied by a tremendous use of residential building materials and has increased the demand for aggregates in concrete-based materials. In the context of France, natural aggregate quarries are dispatched throughout the various regions and generally seem to satisfy the need for aggregates in residential construction. Such however is not the case in those fast growing cities/regions with few natural aggregate quarries. As a follow-up to the waste framework directive 2008/98/EC urging better resource use, this paper explores the ability to achieve circularity practices in residential building materials in French regions. To do so, the framework proposed in this paper aims to close the loop of residential building materials in France and reduce its natural aggregates' consumption. Stock and flows of materials consumed, construction and demolition wastes generated and recycled materials from this sector were assessed through a regional-level material flow analysis. Based on our results, an average reduction in regional natural aggregate extraction of 20 % is obtained when using stock and flows of recycled aggregates stemming from the residential component of construction and demolition wastes and re-injected in new dwellings. The residential wastes employed to reduce natural resource extraction include: concrete, block concrete, stone, solid and hollow bricks from baked clay, tiles, mortar, mineral plaster, glass, sand, and asphalt. The findings of this study also present an overview of the locks and opportunities to achieving the sustainable use of residential building materials. Image 1 • Guidelines for circular economy in French residential sector are provided. • Framework approach for identifying the potential stock of residential building materials is provided. • Main locks and opportunities to unleash the implementation of circular economy in French residential sector are presented. [ABSTRACT FROM AUTHOR]

Worldwide Oil & Gas exploitation industry has a vital and dynamic role to play in the global energy matrix. In any Oil & Gas exploitation mission, drilling operations have the potential to generate substantial quantity of wastes. Drilling fluids and cuttings are considered as hazardous waste, very complex and difficult to be managed due to several impurities (i.,e heavy metals, etc). At the same time, circular economy is gaining cumulative attention in Europe and around the world as a potential way for our humanity to growth prosperity, while reducing dependence on primary materials and energy. The paper through end-of-waste criteria concept and quality protocol development, declassified oil-based drilling cuttings (from Cyprus Oil & Gas Exploitation program) after their treatment through Thermomechanical Cuttings Cleaning process, in order to be used as alternative aggregated and/or construction material and/or cement production (or other civil engineering works), promoting at the same time a valuable and sustainable solution based on circular economy concept. The results showed that, the final solid waste from Thermomechanical Cuttings Cleaning process can be used as raw material for civil engineering works replacing natural resource, if solid waste from the Thermomechanical Cuttings Cleaning process can met the defined quality protocol limits. The results are considered vital for offshores, policy makers, consultant engineers, as well as competent authorities, which try to find an acceptable and at the same time sustainable solution, to monitor and assess drilling waste which should be managed in a safe way, that may not have any undesirable effect on the environment. [Display omitted] • Drilling waste management through end-of-waste criteria (EWC) development. • Drilling waste to be used as aggregates and construction materials. • Quality protocols to define EWC for drilling waste. • Drilling cutting sustainable management approach. • Oil-based drilling cuttings treatment after Thermomechanical Cuttings Cleaning process. [ABSTRACT FROM AUTHOR]

The study attempts to use post-production waste in the form of basalt powder for the production of autoclaved bricks, consisting of sand, lime and water. The research results show that basalt powder can be successfully used in their production. The paper compares traditional bricks and bricks made of raw material mass containing 10%, 20% and 30% of basalt powder addition. The study also investigated the influence of the use of variable amounts of water and its influence on the course of processes taking place in bricks. Tests for compressive strength, water absorption, capillary rise, tightness, porosity, density, volumetric density, mercury porosimetry, optical and scanning microscopy were carried out. The best results were obtained for samples with the addition of 10% basalt powder and 10% water. They were characterized by the highest compressive strength, high tightness, moderate water absorption and a high proportion of closed pores in the sample. Nevertheless, all tested samples meet the requirements for wall building materials. The results of scanning microscopy show that all samples have a similar microstructure, C-S-H phases and tobermorite were formed. The tests carried out have shown that by adding waste in the form of basalt powder, it is possible to obtain a lower brick price and better parameters compared to traditional silicates. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic has not only caused a global health crisis, but it has also had significant environmental and human consequences. During the COVID-19 pandemic, this study focused on emerging challenges in managing healthy personal protective materials (HPPM) in Kingdom of Saudi Arabia, using silty sand (SM) soil as an example since it covers large areas in KSA and in the whole world. The main objective of this paper is to find a novel way to minimize pandemic-related waste by using HPPM as waste materials in road construction. For the first time, a series of experiments was conducted on a mixture of different percentages of shredded HPPM (0, 0.5, 1 and 2%) added to the silty sand (SM) soil for road applications, including soil classification according to the USCS, modified compaction, UCS, UPV, and CBR. In addition, a numerical simulation was performed using geotechnical-based software Plaxis 3D to study the performance of the soil-HPPM mix as a subbase layer in the paving structure under heavy traffic loading. The modified compaction test results show that there is an increase in the optimum moisture content with increasing the HPPM contents from 0.5% to 1% and 2%. However, a reduction in the maximum dry density is observed. The values of dry density and water content at 0%, 0.5%, 1% and 2% pf HPPM are 2.045, 1.98, 1.86 and 1.8 g/cm3 and 7.65% 8%, 8.5% and 9.5%, respectively. The soaked CBR values at 0, 0.5, 1 and 2% HPPM are 23, 30, 8, 2% with the maximum value attained with the addition of 0.5% HPPM. The results of UCS were with the same percentages of HPPM 430, 450, 430 and 415 kPa, respectively, with the maximum value attained with 0.5% HPPM addition as well. In contrast, the values of UVP at 0%, 0.5%, 1% and 2% are 978.5, 680.3, 489.4 and 323.6 m/s, respectively, confirming the trends obtained by modified compaction test results. The simulation results confirm this conclusion that the soil-HPPM mix show a superior performance when used as a subbase layer and reduced vertical displacement by a percentage of 11% compared to the normal subbase material. By eliminating HPPM especially facemasks from the landfill lifecycle, incorporating them into high quality construction material production has the potential to deliver significant environmental benefits. [Display omitted] 1 Influence of polypropylene (HPPM) fibres on the performance of sandy soil is clearly studied. 2 The optimum fibres content is obtained as 0.5% volume fraction. 3 Positive improvement is also noticed in unconfined compressive strength and compaction after adding HPPM fibres. 4 Fibres play a major role in crack bridging. [ABSTRACT FROM AUTHOR]

With the unprecedented global growth of Photovoltaic (PV) panels installation at the annual growth rate of 25–30%, their appropriate End-of-Life (EoL) management gets into focus. The major gap is currently a strategic pathway that facilitates internationally closed-loop supply chain (CLSC) leading to a circular economy from the management point of views. This paper introduces a universal framework for sustainable management of about 5000 GW PV products by 2050 and illuminates the different boundaries and elements that influence the circular economy. There is a minimum of 24 types of substances embedded in PV waste flow which are classified into 6 categories. The research findings estimate 60–80 million tons (MT) of PV waste by 2050 which entails proactive strategy for EoL treatment. Latest update of WEEE Directive in 2019 enforces 85% recovery and 80% preparation for recycling of PV panels. If an environmentally friendly treatment pathway could be achieved and the recovery rate and purity level meet the market demand, there is strong potential for a circular economy, but it needs proper marginalization at the management levels. This study indicated that the PV panels' sustainability should be broken down into three principal levels comprising product and component (Macroscopic), material (Mesoscopic), substances (Microscopic). In each level, the associated parties were introduced, and critical elements were discussed. The parties at the macroscopic level mostly consider the projection of the waste, awareness, and marketing of the recovered materials. While the environmental impacts, treatment pathway and its standard are covered by the associated parties at the mesoscopic level. The micro-management more concerns the monitoring of the purity level and transparent movement of the recovered materials and substances into the new industry and new market and highlights further consideration on the regulation at the international and national levels in this case. [Display omitted] • PV waste management should be categorized into three levels of macroscopic, mesoscopic and microscopic scales. • To achieve sustainability and a circular economy, the development of a global monitoring system is required. • The purity level of the recovered materials has a key towards sustainability and circular economy. • The success of any PV waste management strategy highly depends on public awareness and active marketing program. • The recovered PV materials construction, cosmetic and paint making, and battery industries. [ABSTRACT FROM AUTHOR]

Construction and demolition waste (CDW) is a priority for many policies at global level. This is due to the high volume of CDW that is produced and its inadequate management. This situation leads to serious environmental effects, which are mainly associated with manufacturing processes for new building materials because of low product recovery rates. In this context, the concept of Circular Economy (CE) is a potential solution in many sectors, as it involves more efficient use of resources and energy, which leads to waste minimization and reduction of the environmental impacts of product cycles. Moreover, it represents potential economic opportunities. The main aim of this study was to identify factors that could influence the adoption of the Circular Economy concept in the construction and demolition sector. A systematic literature review was conducted to understand the main strategies involved in the development of integral circular strategies. The main contribution of this paper is a theoretical framework for the Circular Economy in the construction and demolition sector. The framework is comprised of 14 strategies within the five lifecycle stages of construction and demolition activities. Particularly, the framework emphasizes waste management and recirculation of recovered materials for their use as secondary building materials. • A systematic literature review on CE within the CDW sector is provided. • Key strategies for CE on CDW are identified and classified in five lifecycle stages. • An integrative framework approach for CE adoption in the CDW sector is provided. • Preconstruction/demolition strategies have the highest influence on CE operation. [ABSTRACT FROM AUTHOR]