Construction and Demolition Waste (CDW) valorization in alkali activated bricks

2019 ◽  
pp. 495-499
Author(s):  
I. Lancellotti ◽  
V. Vezzali ◽  
L. Barbieri ◽  
C. Leonelli ◽  
A. Grillenzoni
Keyword(s):  
Construction And Demolition Waste ◽  
Demolition Waste ◽  
Alkali Activated

scholarly journals Acid Resistance of Lightweight Brick Powder Based Alkali Activated Material from Construction and Demolition Wastes

2018 ◽  
Author(s):  
Kai Tai Wan ◽  
Amende Sivanathan ◽  
Gediminas Kastiukas ◽  
Xiangming Zhou
Keyword(s):  
Acid Resistance ◽  
Strength Loss ◽  
Construction And Demolition Waste ◽  
Demolition Waste ◽  
Construction And Demolition Wastes ◽  
Brick Powder ◽  
Structural Applications ◽  
The Matrix ◽  
Similar Density ◽  
Alkali Activated

The annual construction and demolition waste (CDW) generated from EU construction sector was 850 million tons, which represented 31% of the total waste generation and about 28% of CDW was ceramics (bricks and tiles). In this study, the feasibility of using CDW brick powder as the precursor of alkali activated mortar (AAM) and extruded polystyrene (XPS) as the lightweight aggregates to form lightweight brick powder AAM (LW-BP-AAM) for non-structural applications was investigated. The thermal conductivity of LP-BPAAM was 0.112 W/m·K with density of about 1,135 kg/m3 which was lower than the counterparts with similar density in literature. The acid resistance of LW-BP-AAM is comparable to conventional fly ash based AAM and superior than ordinary Portland cement. From the scanning electron microscopy with energy dispersive X-ray spectroscopy, there was no severe damage on the surface of LW-BP-AAM but aluminate was removed from the matrix which was further verified in Fourier transform infrared spectroscopy. The mass and strength loss of LP-BP-AAM was 1.5% and 33%, respectively. Although the compressive strength of the LP-BP-AAM was low (about 1.8 MPa), it can be improved by optimising the particle size of the XPS aggregates.

scholarly journals Construction and Demolition Waste as Recycled Aggregates in Alkali-Activated Concretes

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4016 ◽  
Author(s):  
Zahra Abdollahnejad ◽  
Mohammad Mastali ◽  
Mahroo Falah ◽  
Tero Luukkonen ◽  
Mehran Mazari ◽  
...  
Keyword(s):  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Demolition Waste ◽  
High Calcium ◽  
High Calcium Concentration ◽  
One Step ◽  
Hardened State ◽  
Global Construction ◽  
Alkali Activated Concrete ◽  
Alkali Activated

The growth of global construction has contributed to an inevitable increase in the amount of construction and demolition (C&D) waste, and the recycling of C&D waste as aggregates in concrete is receiving increased interest, resulting in less demand for normal aggregates and bringing a potential solution for the landfilling of wastes. Recently, several studies have focused on the use of C&D waste in alkali-activated concrete to move one step closer to sustainable concretes. This paper focuses on the main mechanisms of using C&D waste in the resulting physical, mechanical, and durability properties of alkali-activated concrete in fresh and hardened state properties. The main difficulties observed with recycled aggregates (RA) in concrete, such as high levels of water demand, porous structure, and low mechanical strength, occur in RA alkali-activated concretes. These are associated with the highly porous nature and defects of RA. However, the high calcium concentration of RA affects the binder gel products, accelerates the hardening rate of the concrete, and reduces the flowability of alkali-activated concretes. For this reason, several techniques have been investigated for modifying the water content and workability of the fresh matrix and for treating RA and RA/alkali-activated binder interactions to produce more sustainable alkali-activated concretes.

Stabilisation of construction and demolition waste with a high fines content using alkali activated fly ash

2018 ◽  
Vol 170 ◽  
pp. 26-39 ◽  
Author(s):  
Nuno Cristelo ◽  
Ana Fernández-Jiménez ◽  
Castorina Vieira ◽  
Tiago Miranda ◽  
Ángel Palomo
Keyword(s):  
Fly Ash ◽  
Construction And Demolition Waste ◽  
Demolition Waste ◽  
Fines Content ◽  
Alkali Activated

scholarly journals Construction and Demolition Waste (CDW) Recycling—As Both Binder and Aggregates—In Alkali-Activated Materials: A Novel Re-Use Concept

2020 ◽  
Vol 12 (14) ◽  
pp. 5775 ◽  
Author(s):  
Rafael A. Robayo-Salazar ◽  
William Valencia-Saavedra ◽  
Ruby Mejía de Gutiérrez
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Circular Economy ◽  
Room Temperature ◽  
Heat Of Hydration ◽  
Construction And Demolition Waste ◽  
Demolition Waste ◽  
High Class ◽  
Construction And Demolition Wastes ◽  
Alkali Activated

This article demonstrates the possibility of producing alkali-activated materials (AAM) from a mixture of mechanically processed concrete, ceramic, masonry, and mortar wastes, as a sustainable alternative for recycling construction and demolition wastes (CDWs) under real conditions. The addition of 10% Portland cement allowed the materials to cure at room temperature (25 °C). CDW binder achieved a compressive strength of up to 43.9 MPa and it was classified as a general use and low heat of hydration cement according to ASTM C1157. The concrete produced with this cement and the crushed aggregates also from CDW reported a compressive strength of 33.9 MPa at 28 days of curing and it was possible to produce a high-class structural block with 26.1 MPa according to ASTM C90. These results are considered one option in making full use of CDWs as binder and aggregates, using alkaline activation technology thereby meeting the zero-waste objective within the concept of the circular economy.

scholarly journals Viability of the use of construction and demolition waste aggregates in alkali-activated mortars

2018 ◽  
Vol 68 (331) ◽  
pp. 164 ◽  
Author(s):  
M. M. Alonso ◽  
A. Rodríguez ◽  
F. Puertas
Keyword(s):  
Fire Resistance ◽  
Mechanical Performance ◽  
Total Porosity ◽  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Partial Replacement ◽  
Demolition Waste ◽  
Alkali Activated

This study explores the technological feasibility of using construction and demolition waste (C&DW) as recycled aggregate in alkali activated mortars, ascertaining the mechanical and microstructural behavior. Shrinkage behavior of alkali activated slag mortars (AAS) and fire resistance of alkali activated fly ash (AAFA) incorporating recycled aggregates have been also tested Normalized siliceous sand and two types of recycled concrete aggregates were used in the mixes at different proportions. The findings showed that water demand was higher in mortars prepared with recycled aggregate. Partial replacement (20% - 80/20) of conventional aggregate with the recycled material was also observed to yield mortars with high mechanical strength, although total porosity also rose. Total replaclement, gave worse mechanical performance however. Fire resistance and shrinkage studies conducted indicated that alkaline cement mortars prepared with 80/20 recycled aggregated exhibit acceptable performance.

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