•The application of carbonation of cement-based materials for carbon dioxide sequestration are summarized.•Revealing the carbonation acceleration mechanism and analyzing the influencing ...factors.•Research needs and application opportunities are discussed and recommended.
In the past twenty years, significant researches have been conducted on the accelerating fixation technologies of carbon dioxide through the carbonation reaction of cement-based materials. In this study, the published literature on the application of carbonation of cement-based materials for carbon dioxide sequestration has been reviewed, the carbon dioxide sequestration capacity, the carbonation effect on the physical and mechanical behavior of recycled aggregates and concrete, the efficiency improvement methods, and the acceleration methods on the mechanical behavior of cement-based materials are discussed and summarized in detail. The comparative discussion results show that carbonation could effectively improve the mechanical performance of recycled aggregates and concrete. The parameters of liquid water content, sample size, environmental pressure, carbon dioxide concentration, and temperature significantly affect the sequestration efficiency of carbon dioxide of cement-based materials. Besides, the future application proposals of fast carbon dioxide sequestration technologies in the industrial areas and cement-based material recycling have been put forward. This review could facilitate the investigation and application of fast carbon dioxide sequestration technologies through the carbonation of cement-based materials.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The relatively low strength and brittleness are believed to be two main factors restricting the widely use of coal reject concrete (i.e. CRC) in practical applications. This paper presents a concept ...of the novel hybrid concrete column incorporating fibre-reinforced polymer (i.e. FRP), termed FRP-confined CRC (i.e. FCCR) columns, to widen the use of CRC. The systematic compression tests on natural aggregates concrete (i.e NAC) and CRC with the large range replacement ratios of natural aggregates in volume (i.e. 0%, 25%, 50%, 75% and 100%) were firstly carried out, followed by the compressive tests on FCCR columns. Test variables covered the thickness of FRP jacket (i.e.0-ply, 2-ply and 4-ply), the replacement ratio of natural aggregates and the particle size of coal reject. In parallel, the FRP-confined NAC columns (i.e. FCNA) columns have been prepared and tested for comparison. Test results showed that the compressive strength of CRC decreases with the increased replacement ratio of natural aggregates. When the CRC is confined by the exterior FRP jacket, both the compressive strength and the ductility of which have been significantly enhanced. Furthermore, these FCCR columns with a thicker FRP jacket generally exhibited the superior compressive behaviour. The analysis-oriented model developed by Jiang and Teng for FCNA was adopted to predict the compressive behaviour of FCCR. The feasibility of Jiang and Teng’s model for predicting the behaviour of FCCR with the replacement of fine aggregate was verified.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The construction industry consumes significant quantities of mineral-based materials, thereby causing pollution and raw material depletion. To meet projected demands for new buildings, while ...simultaneously reducing the use of non-renewable materials and fossil-based carbon, there is therefore a strong drive to develop alternative, renewable materials to replace those currently used in this sector. In the present study, we investigate the formulation of waste-based biopolymer slurries for 3D printing as a path towards more sustainable construction elements. The printing formulation was based on xanthan gum as a binder with lignocellulosic waste fibres and particles for reinforcement. At the same time, flow properties were controlled using a combination of bio-based plasticiser (glycerol) and water. First, the amounts of water, plasticiser and waste fillers were optimised to minimise shrinkage and deformation while obtaining the best possible mechanical properties after drying. Different reinforcing fillers were investigated, and it was proven that a minor addition of inorganic material (vermiculite) could significantly improve the material’s mechanical properties during printing and in its final form after drying. Furthermore, it was shown how using calcium ions could enhance the binding effect of the xanthan gum and how combining it with an increase in binder concentration could improve the early-age strength of the printed material. The optimised formulations were proven suitable for 3D printing. The addition of vermiculite improved weathering resistance and stability during printing (shrinkage and height), which was illustrated in a bench-scale printing test.
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•Water-based slurries help to combine waste and bio-based materials for 3D printing at the architectural scale.•Plasticiser, water, binder, and fillers were optimized to balance flowability and final mechanical properties.•Calcium ions as ionic cross-linker enhances the performance of the binder and improves the 3D printing performance.•Vermiculite doubles the mechanical properties improves weathering resistance and 3D printing performance.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Large quantities of waste generated in the municipal, commercial and industrial and construction and demolition sectors have caused widespread environmental issues. The replacement of virgin ...materials with recycled in pavement construction is a possible solution for waste management and achieving sustainability goals in the infrastructure sector. There are, however, questions about environmental and economic impacts of waste-derived materials in road construction that need to be answered. Life cycle assessment and life cycle cost analysis are two approaches to quantify and assess the environmental performance and the costs of decisions regarding the selection of materials for pavement construction. While considerable research has been conducted on pavement materials, the impacts of particular materials such as recycled concrete aggregates, lignin, waste plastic, recycled glass, crushed brick and crumb rubber are not currently well understood. This research presents a synthesis of the state of the art of selected recycled materials in pavement construction and limitations of existing environmental and economic analysis. A major interest towards recycling of materials and necessity of their sustainability analysis is highlighted. The results indicate that the sustainability analysis of selected recycled materials is in its infancy with considerable inconsistencies, hindering the meaningful comparison of results. Furthermore, exclusion of impacts of maintenance, usage and end of life phases from sustainability analysis, impose uncertainty on the long-term viability of these materials. Further research is needed to develop better understanding of these impacts so that more informed decisions could be made by policy makers.
•LCA and LCCA of waste-derived pavements were reviewed.•The sustainability of pavement is a growing research area in developed countries.•There is inconsistency among the reviewed studies in terms of the system boundary.•No consensus exists on the environmental impacts of recycled materials in pavements.•Most LCCAs focused on production costs without consideration of recycling costs.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Concrete with higher seashell ratio has lower physical and mechanical properties.•Ground seashell aggregate can replace up to 20% natural fine aggregate in concrete.•Up to 50% seashell as a partial ...coarse aggregate can give normal-weight concrete.•Current data on durability of seashell aggregate concrete indicate varied effects.•Sound absorption and thermal insulation studies of seashell concrete are required.
Trends in concrete technology are currently directed towards sourcing alternative sustainable materials for concrete in order to minimise over-reliance on natural resources. Many of the substitute materials used for producing green concrete are recycled materials obtained from industrial wastes and by-products. A promising solution to the challenge of seashell waste management involves utilising seashells as construction materials in concrete. Experimental investigations have been carried out on the use of mollusc seashells such as periwinkle shell, mussel shell, oyster shell, cockle shell, crepidula shell, clam shell and scallop shell as aggregate replacement materials in concrete. The seashells were utilised as partial or total replacement of fine and coarse aggregates in concrete. This paper is a literature review of seashell aggregate concrete. The paper first presents an overview of the physical, mechanical and chemical properties of the seashells. This is followed by a discussion of the physical, mechanical and durability properties of seashell aggregate concrete in fresh and hardened states. Possible applications in the construction industry are also highlighted. Mollusc seashells have similar chemical composition with limestone-type aggregates but characteristically contain traces of chloride and sulphate salts. Although inclusion of seashell aggregate reduces the physico-mechanical properties of concrete, utilising some seashells as partial coarse aggregate at up to 50% substitution level can produce normal-weight concrete for non-structural and low-strength structural functions. The current understanding of seashell aggregate concrete provides a basis for further research on various aspects of its behaviour including the sound absorption and thermal insulation properties.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Dry concrete exhibits significantly different mechanical properties and failure patterns under dynamic loads from those under static conditions. Considering the practical applications of dry ...concrete, the flexural impact load renders its units/structures susceptible to unpredictable damage or even failure. In this study, the modified low-velocity drop-weight impact test was conducted on steel fibre-reinforced dry UHPC (FR-DUHPC) beam samples to simulate the frequent and multiple impact loads. The effects of steel fibre length, mixing method, fly ash content and crumb rubber addition on the impact resistance of FR-DUHPC were evaluated based on dynamic responses. Weibull distribution was then conducted to analyse the failure hit number of concrete samples in consideration of the large value variation. Test results indicated that the flexural impact performance was markedly improved with longer steel fibres, but deteriorated with increased fly ash content (especially at early ages) and considerably degraded with the inclusion of rubber aggregate. Hybrid medium/long fibre reinforcement was proposed for DUHPC that were mainly subjected to impact loads during service, while the fly ash content utilized to partially replace cement was not recommended to exceed 40%. Rubber aggregate was not proposed to be added to dry concrete mixtures since the impact load would greatly accentuate the initial matrix defects caused by the weak bonding. Additionally, the two-parameter Weibull distribution was verified to be a desirable statistical method for analysing the failure blow number of FR-DUHPC under repeated low-speed drop-weight impacts. The impact energy for the practical structural design could be preliminarily computed utilizing the derived Weibull parameters at different levels of reliability.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Extensive studies have been conducted on the use of fibre-reinforced polymer (FRP) as a confining material in hybrid tubular columns for civil construction, where the design of columns is often ...controlled by the stiffness and/or strength requirements. By contrast, the capacity of sustaining large deformation without losing structural integrity can be critical in some applications such as the standing supports for underground mines. This paper presents the conceptual development of a novel column form with large deformation capacity. The novel column consists of an outer FRP tube, and an infill made of coarse lumps/aggregates, which can be from coal rejects or other waste/recycled materials, as well as calcium sulfoaluminate (CSA)-based cementitious material with high water content. In addition to its large deformation capacity, the new column allows the extensive, direct and easy use of waste materials and eliminates the need for mixing concrete on site or transporting commercial concrete. This paper also presents the results from a series of compression tests on the new columns as well as two similar column forms. These tests demonstrate the very large deformation capacity of the new column and show that an existing stress-strain model for FRP-confined normal concrete can be used to provide reasonable predictions of the behaviour of the confined infill material in the new column. The potential applications of the new column and the needs for future research are also discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Awareness of environmental pollution, interest in recycling, and the importance of closed-loop supply chain management are all on the rise. In a closed-loop supply chain, production planning is ...influenced by uncertainty not only from customers’ demand, but also from collectors due to difficulties in the reverse logistics flow. Therefore, it is important to develop a robust closed-loop supply chain model to respond to uncertainty from reverse logistics. In this study, we develop a deterministic mixed-integer optimization model and robust counterparts to cope with the uncertainty of recycled products and customer demand in the fashion industry. We show that a robust counterpart with a budget of uncertainty is equivalent to a robust counterpart with a box uncertainty under special conditions. To avoid the conservatism of a robust solution, an alternative optimization problem is developed to take advantage of the budget of uncertainty. To verify the performance of the proposed model, numerical experiments are conducted. The simulation results show the proposed model responds robustly to uncertainty and is superior to a deterministic model and other robust counterparts.
•Reverse logistics flow and demand uncertainties affect closed-loop supply chains.•Budget of uncertainty helps mitigate conservatism in robust counterpart models.•Suppliers with low uncertainty have a positive effect on gross profit.•A robust optimization model provides good performance under uncertainty.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•Addition of RAP contents can significantly increase the MR value of the blended sample.•Addition of RAP contents can significantly increase the residual strain of the blended sample.•Under ...controlled conditions RAP can be used in base/subbase layer of the pavement.
In current road and pavement engineering practices, the lack of fresh natural aggregate (granular material) supplies with increasing processing costs have led to use various reclaimed/recycled materials from old structures as a source of construction materials. Reclaimed Asphalt Pavement (RAP), and Recycled Concrete Aggregate (RCA) have been used as aggregates for pavement construction for some time. This study is focused on the characterization of blended materials containing 50% and 75% of RAP with fresh granular materials and RCA to evaluate whether they are suitable for granular base/subbase layers of flexible pavements. A series of laboratory tests was performed to determine the resilient modulus (MR) and the constrained modulus (Mc) for both fresh granular materials and their blends. Statistically, the notable increase was found in the MR values of the blended samples containing 75% RAP material and 25% fresh granular, particularly at higher levels of bulk stresses. It was also found that the accumulative strains during cyclic loading generally increase with an increase in the percentage of RAP contents in the blended samples. Mc test results show an increasing trend with the increasing level of axial stress, however, Mc value decreases with increasing percentage of the RAP content. Never-the-less, the t-test showed that accumulative strains during Mc tests were found to increase significantly with an increase in the percentage of RAP contents.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The research aims to investigate the effect of graphene nanoplatelets (GNPs) on mechanical properties, workability as well as microstructure of fly ash-based geopolymer concrete containing crumb ...rubber (CR) through experiments and response surface methodology (RSM). A total of 20 mix designs were utilized, with 10–30% volume replacement of fine aggregate with CR and addition of 0.1–0.4% GNPs by weight of binder. All mix designs were studied for attributes including slump flow, compressive strength, stress-strain behavior, modulus of elasticity, tensile strength, flexural strength, toughness, impact resistance, water absorption, and porosity. Morphological changes due to crack formation, microstructure, and interfacial interaction between aggregate and mortar were evaluated using field emission scanning electron microscopy (FESEM). Vickers microhardness tests were carried out from the surface of aggregate towards the matrix to evaluate the interfacial transition zone. Results indicated that CR replacement reduced the mechanical properties of geopolymer concrete, while GNPs inclusion mitigated the negative effects of CR and significantly enhanced the properties of the geopolymer concrete. Results also revealed that 0.3% addition of GNPs increased the compressive strength, elastic modulus, tensile strength, and flexural toughness of the concrete containing the CR. Moreover, addition of 0.3% GNPs in specimens having 30% CR enhanced the average microhardness by 34%, which demonstrates that GNPs addition improved the matrix compactness and interfacial transition zone between CR and matrix. Multi-objective optimization with RSM was accomplished for the combined use of CR and GNPs in fly ash-based geopolymer concrete. RSM results showed that combination of 10% CR and 0.2% GNPs is the best combination for achieving the highest strength properties with the lowest percentage of GNPs.
•GNPs enhanced the strengths of geopolymer concrete with crumb rubber (CR).•Vickers microhardness was tested to evaluate the interfacial transition zone.•The optimization by RSM suggested the best mix of 10% CR and 0.2% GNPs.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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