Environmental assessment, mechanical behavior and new leaching impact proposal of mixed recycled aggregates to be used in road construction

Agrela, Francisco; Díaz-López, José Luis; Rosales, Julia; Cuenca-Moyano, G.M.; Cano, H.; Cabrera, Manuel

doi:10.1016/j.jclepro.2020.124362

Cited by 26 publications

(12 citation statements)

References 36 publications

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“…For this reason, it is necessary to reconcile the industrial growth of nations with the preservation of the environment [7], in such a way that an effective recycling route for CDWs is their crushing, grinding and separation to be used as aggregates [8]. At present, the most direct application of recycled aggregates is the execution of roads [9], prefabricated for building and civil works [10], and as a partial replacement for natural aggregate in the production of mortars and concrete [11]. However, several authors have investigated the properties of these raw materials and have made it possible to extend the field of application of these aggregates for the production of new construction materials [12,13].…”

Section: Introductionmentioning

confidence: 99%

Influence of Recycled Aggregates on the Mechanical Properties of Synthetic Fibers-Reinforced Masonry Mortars

et al. 2021

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The construction sector is one of the main consumers of raw materials and generates a high volume of waste within the European Union. The search for new materials that are more sustainable and respectful of the environment has become a challenge for countries with a high degree of industrialization. In this work, a study of the most relevant properties of masonry mortars made with recycled aggregates and reinforced with synthetic fibers was carried out. Three types of aggregates were used—natural, concrete recycling and ceramic recycling—and two types of reinforcing fibers: polypropylene and polyolefin. In this way, various tests of physical-mechanical characterization and a statistical analysis of the results were carried out. It has been shown that the mortars made from aggregate recycled concrete and reinforced with polypropylene fiber are the ones with the best properties for application in the construction sector, although without improving the properties of traditional mortars made from natural aggregate and without fibers.

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Section: Introductionmentioning

confidence: 99%

Influence of Recycled Aggregates on the Mechanical Properties of Synthetic Fibers-Reinforced Masonry Mortars

et al. 2021

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“…As shown in Figure 4, SO 4 is a critical parameter for both CDWs and RAs, and it is generally released from mixed CDWs due to the presence of gypsum, ceramic materials, and mortar particles [17,19,20,23,30,36]. In particular, as shown in Figure 4 (right), over 50% of all samples analyzed (box with vertical lines) had concentrations above the regulatory limit of 250 mg/L.…”

Section: Leaching Behavior Of Cdws and Rasmentioning

confidence: 92%

“…In this context, in the literature, there are many experimental studies carried out on CDWs and RAs aimed at evaluating the environmental performance of these materials [18,19,23,[32][33][34][35][36], while there are very few studies that evaluate these properties using a statistical approach [37]. Therefore, the objective of this study is to evaluate the influence of the following parameters on the leaching behavior of CDWs and RAs by state of the art analysis and, simultaneously, assess the environmental behavior of both CDWs and RAs by analyzing characterization tests (e.g., chemical composition and leaching test) carried out on such materials.…”

Section: Introductionmentioning

confidence: 99%

Chemical and Leaching Behavior of Construction and Demolition Wastes and Recycled Aggregates

et al. 2020

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Construction and demolition wastes are widely recognized as the main waste stream in the EU, and their recycling and recovery is an important issue in sustainable building industry development. The composition of construction and demolition wastes is highly heterogeneous and is influenced by several factors, including the raw materials and construction products used. The environmental performance of these materials are therefore considerably variable and, in some cases, do not comply with the regulatory limits established to ensure the protection of the natural environment. In this context, this paper presents a data analysis on the environmental behavior of construction and demolition wastes and recycled aggregates in terms of both chemical composition and the release of contaminants according to a leaching test. Subsequently, the most critical parameters for recovery were identified and statistically evaluated. The leaching results showed that SO4, Cu, and COD are critical compounds for both CDWs and RAs.

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“…Substituting Equation (8) into Equation (7) to obtain the relationship between the peak stress and confining pressure of specimens at different furnace slag substitution rates gave…”

Section: Stress Peak Law Analysismentioning

confidence: 99%

“…At the moment, China has accumulated >8 billion tons of coal gangue, which covers an area of ~70 km 2 and causes multiple environmental issues. Consequently, using coal gangue as a road base filling material can not only prevent pollution but also reduce natural resource exploitation, thus paving the approach for high-value and large-scale resource utilization [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Mechanical Properties of Furnace Slag and Coal Gangue Mixtures Stabilized by Cement and Fly Ash

Zhang

Yan

et al. 2021

Materials

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The mechanical properties and strength formation mechanism of cement–fly-ash-stabilized slag–coal gangue mixture were examined using an unconfined compressive strength test, splitting strength test, triaxial test, and scanning electron microscopy to solve the limitations of land occupation and environmental pollution that is caused by fly ash from the Xixia District thermal power plant in Yinchuan, slag from the Ningdong slag yard, and washed coal gangue. Its performance as a pavement base mixture on the road was investigated. The results demonstrated that as the slag replacement rate increased, the maximum water content increased while the maximum dry density decreased. The addition of slag reduced the unconfined compressive strength and splitting strength of the specimens; furthermore, the higher the slag substitution rate, the lower the unconfined compressive strength and splitting strength of the specimens. As the cement content increased, the specimen’s unconfined compressive strength increased. Based on the principle of considering the mechanical properties and economic concerns, the slag replacement rate in the actual construction should be ~50% and should not exceed 75%. Based on the relationship between the compressive strength and splitting strength of ordinary concrete, the relationship model between the unconfined compressive strength and splitting strength of cement–fly-ash-stabilized slag–coal gangue was established. The failure mode, stress–strain curve, peak stress, and failure criterion of these specimens were analyzed based on the triaxial test results, and the relationship formulas between the slag substitution rate, cement content, peak stress, and confining pressure were fitted. As per the SEM results, the mixture’s hydration products primarily included amorphous colloidal C-S-H, needle rod ettringite AFt, unhydrated cement clinker particles, and fly ash particles. The analysis of the mixture’s strength formation mechanism showed that the mixture’s strength was the comprehensive embodiment of all factors, such as the microaggregate effect, secondary hydration reaction, and material characteristics.

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Environmental assessment, mechanical behavior and new leaching impact proposal of mixed recycled aggregates to be used in road construction

Cited by 26 publications

References 36 publications

Influence of Recycled Aggregates on the Mechanical Properties of Synthetic Fibers-Reinforced Masonry Mortars

Influence of Recycled Aggregates on the Mechanical Properties of Synthetic Fibers-Reinforced Masonry Mortars

Chemical and Leaching Behavior of Construction and Demolition Wastes and Recycled Aggregates

Mechanical Properties of Furnace Slag and Coal Gangue Mixtures Stabilized by Cement and Fly Ash

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