Comparison of different activators for alkaline activation of construction and demolition wastes

It is clear that construction and demolition wastes (CDW) are constantly increasing throughout the world and these wastes can be used effectively to minimize the consumption of natural resources in the manufacture of more sustainable concrete. The CDW occupy an important segment of world waste production and its generation reached approximately 3 billion tons in 2012 in 40 countries [1]. Although this topic has been studied in the world, it is still valid for the reuse of waste that is constantly increasing, and although in many countries there are already examples of its use this type of concrete in Colombia and in the Medellìn city lacks applications. This project proposes the application of a sustainable concrete made with CDW and coal ash in the Medellín city for its implementation in the construction of urban furniture. A university community diagnosis of the needs in terms of furnishing was made. With the design reached, a modular chair was proposed to enable spaces within the university. The mechanical characteristics of the concrete and the design of the chair are evaluated and a simulation is done through finite elements to evaluate the viability of the proposed concrete, finding that with these properties is possible to manufacture durable and sustainable furniture that serves as an example for the application of sustainable materials

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Modeling materials flow of waste concrete from construction and demolition wastes in Taiwan

Resources Policy ◽

10.1016/s0301-4207(03)00004-7 ◽

2002 ◽

Vol 28 (1-2) ◽

pp. 39-47 ◽

Cited By ~ 64

Author(s):

T.Y. Hsiao ◽

Y.T. Huang ◽

Y.H. Yu ◽

I.K. Wernick

Keyword(s):

Waste Concrete ◽

Construction And Demolition Wastes ◽

Materials Flow

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Leaching Behaviour of Construction and Demolition Wastes and Recycled Aggregates: Statistical Analysis Applied to the Release of Contaminants

Applied Sciences ◽

10.3390/app11146265 ◽

2021 ◽

Vol 11 (14) ◽

pp. 6265

Author(s):

Alessandra Diotti ◽

Giovanni Plizzari ◽

Sabrina Sorlini

Keyword(s):

Particle Size ◽

Statistical Analysis ◽

Raw Materials ◽

Primary Source ◽

Recycled Aggregates ◽

Critical Parameters ◽

Material Particle ◽

Analysis Methodology ◽

Construction And Demolition Wastes ◽

Leaching Behaviour

Construction and demolition wastes represent a primary source of new alternative materials which, if properly recovered, can be used to replace virgin raw materials partially or totally. The distrust of end-users in the use of recycled aggregates is mainly due to the environmental performance of these materials. In particular, the release of pollutants into the surrounding environment appears to be the aspect of greatest concern. This is because these materials are characterized by a strong heterogeneity which can sometimes lead to contaminant releases above the legal limits for recovery. In this context, an analysis of the leaching behaviour of both CDWs and RAs was conducted by applying a statistical analysis methodology. Subsequently, to evaluate the influence of the particle size and the volumetric reduction of the material on the release of contaminants, several experimental leaching tests were carried out according to the UNI EN 12457-2 and UNI EN 12457-4 standards. The results obtained show that chromium, mercury, and COD are the most critical parameters for both CDWs and RAs. Moreover, the material particle size generally affects the release of contaminants (i.e., finer particles showed higher releases), while the crushing process does not always involve higher releases than the sieving process.

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