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 (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 Using Green Supplementary Materials to Achieve More Ductile ECC

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 858 ◽  
Author(s):  
Yichao Wang ◽  
Zhigang Zhang ◽  
Jiangtao Yu ◽  
Jianzhuang Xiao ◽  
Qingfeng Xu
Keyword(s):  
Fracture Toughness ◽  
Tensile Strain ◽  
Tension Test ◽  
Construction And Demolition Waste ◽  
Demolition Waste ◽  
Strain Capacity ◽  
Fiber Bridging ◽  
Matrix Fracture ◽  
The Matrix ◽  
Tensile Strain Capacity

To improve the greenness and deformability of engineered cementitious composites (ECC), recycled powder (RP) from construction and demolition waste with an average size of 45 μm and crumb rubber (CR) of two particle sizes (40CR and 80CR) were used as supplements in the mix. In the present study, fly ash and silica sand used in ECC were replaced by RP (50% and 100% by weight) and CR (13% and 30% by weight), respectively. The tension test and compression test demonstrated that RP and CR incorporation has a positive effect on the deformability of ECC, especially on the tensile strain capacity. The highest tensile strain capacity was up to 12%, which is almost 3 times that of the average ECC. The fiber bridging capacity obtained from a single crack tension test and the matrix fracture toughness obtained from 3-point bending were used to analyze the influence of RP and CR at the meso-scale. It is indicated that the replacement of sand by CR lowers the matrix fracture toughness without decreasing the fiber bridging capacity. Accordingly, an explanation was achieved for the exceeding deformability of ECC incorporated with RP and CR based on the pseudo-strain hardening (PSH) index.

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 Recycling construction and demolition wastes within hydraulically bound mixtures for road pavements

2021 ◽  
Author(s):  
Marco Pasetto ◽  
Andrea Baliello ◽  
Giovanni Giacomello ◽  
Emiliano Pasquini
Keyword(s):  
Construction Industry ◽  
Environmental Sustainability ◽  
Road Construction ◽  
Construction And Demolition Waste ◽  
Demolition Waste ◽  
The Road ◽  
Construction And Demolition Wastes ◽  
European Standards ◽  
Water Contents ◽  
Mineral Aggregates

The recycling of Construction and Demolition Waste (CDW) is an actual challenge regarding the construction industry because of the increasing volumes worldwide produced and the related environmental impacts. In this regard, a suitable application can be developed in the road construction field, in particular for the production of hydraulically bound mixtures for road subbase and foundation layers. In this sense, the reuse of CDW can strongly enhance the environmental sustainability of road construction thanks to the achievable savings of natural resources such as the mineral aggregates obtained from quarry operations. Indeed, the utilization of a CDW as aggregate must ensure the production of mixtures with adequate mechanical and environmental characteristics. Therefore, the herein paper presents the results of an experimental characterization aimed at assessing the suitability of CDW for the production of hydraulically bound mixtures for road pavements. In particular, the main mechanical properties of some mixtures including different percentages and gradations of CDW were analysed and compared with the main technical prescriptions and classification criteria indicated by the reference European standards. Basic properties and production processes of the CDW materials were also studied to determine their effects on the optimum binder and water contents of the mixtures. The research clearly demonstrated that the use of a preliminary-washed CDW coarse aggregate was able to enhance the overall structural properties and the water resistance of mixtures.

Optimizing construction and demolition waste transportation for sustainable construction projects

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nehal Elshaboury ◽  
Mohamed Marzouk
Keyword(s):  
Sensitivity Analysis ◽  
Construction Projects ◽  
Pareto Frontier ◽  
Construction And Demolition Waste ◽  
Sustainable Construction ◽  
Algorithm Optimization ◽  
Demolition Waste ◽  
Content Type ◽  
Construction And Demolition Wastes ◽  
High Level

PurposeThere have been numerous efforts to tackle the problem of accumulated construction and demolition wastes worldwide. In this regard, this study develops a model for identifying the optimum fleet required for waste transportation. The proposed model is validated through a case study from the construction sector in New Cairo, Egypt.Design/methodology/approachVarious fleet combinations are assessed against the time, cost, energy and emissions generated from waste transportation. Genetic algorithm optimization is performed to select the near-optimum solutions. Complex proportional assessment and operational competitiveness rating analysis decision-making techniques are applied to rank Pareto frontier solutions. These rankings are aggregated using an ensemble approach based on the half-quadratic theory. Finally, a sensitivity analysis is implemented to determine the most sensitive attribute.FindingsThe results reveal that the optimum fleet required for construction and demolition wastes (CDW) transportation consists of one wheel loader of bucket capacity 2.5 cubic meters and nine trucks of capacity 22 cubic meters. Furthermore, consensus index and trust level of 0.999 are obtained for the final ranking. This indicates that there is a high level of agreement between the rankings. Moreover, the most sensitive criterion (i.e. energy) is identified using a sensitivity analysis.Originality/valueThis study proposes an efficient and effective construction and demolition waste transportation strategy that will lead to economic gains and protect the environment. It aims to select the optimum fleet required for waste transportation based on economic, social and environmental aspects. The usefulness of this study is establishing a consensual decision through the aggregation of conflicting decision makers' preferences in waste transportation and management.

scholarly journals Behaviour and Properties of Eco-Cement Pastes Elaborated with Recycled Concrete Powder from Construction and Demolition Wastes

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1299
Author(s):  
Laura Caneda-Martínez ◽  
Manuel Monasterio ◽  
Jaime Moreno-Juez ◽  
Sagrario Martínez-Ramírez ◽  
Rosario García ◽  
...  
Keyword(s):  
Blended Cement ◽  
Recycled Concrete ◽  
Environmental Benefits ◽  
Construction And Demolition Waste ◽  
Replacement Rate ◽  
Demolition Waste ◽  
Cement Pastes ◽  
Blended Cements ◽  
Construction And Demolition Wastes ◽  
Refinement Process

This work analyses the influence of fine concrete fractions (<5 mm) of different natures —calcareous (HcG) and siliceous (HsT)—obtained from construction and demolition waste (C&DW) on the behaviour of blended cement pastes with partial replacements between 5 and 10%. The two C&DW fractions were characterised by different instrumental techniques. Subsequently, their lime-fixing capacity and the physico-mechanical properties of the blended cement pastes were analysed. Lastly, the environmental benefits of reusing these fine wastes in the manufacture of future eco-efficient cement pastes were examined. The results show that HsT and HcG exhibit weak pozzolanic activity, owing to their low reactive silica and alumina content. Despite this, the new cement pastes meet the physical and mechanical requirements of the existing regulations for common cements. It should be highlighted that the blended cement pastes initially showed a coarser pore network, but then they underwent a refinement process between 2 and 28 days, along with a gain in compressive strength, possibly due to the double pozzolanic and filler effect of the wastes. The environmental viability of the blended cements was evaluated in a Life Cycle Assessment (LCA) concluding that the overall environmental impact could be reduced in the same proportion of the replacement rate. This is in line with the Circular Economy goals and the 2030 Agenda for Sustainable Development.

scholarly journals Investigation of Properties of Concrete Produced with Recycled Aggregates

2021 ◽  
Vol 1 (2) ◽  
pp. 26-34
Author(s):  
Gökhan KAPLAN
Keyword(s):  
Acid Resistance ◽  
Recycled Aggregate Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Environmental Damage ◽  
Freezing And Thawing ◽  
Demolition Waste ◽  
Concrete Production ◽  
Strength And Durability

The greatest frequently applied construction substantial in the construction sector is concrete. Natural resources are mostly used in concrete production. While environmental resources are being consumed, concrete environmental pollution increases during urban transformation or reconstruction. In sustainable life, environmental damage caused by construction demolition wastes necessitates the use of recovered aggregate. Recycled aggregate is a term used to depict squashed solid, mortar, blocks or black-top from development trash that is reused in other structure ventures. Reused total is delivered by pounding annihilated waste to recover the total. For as far back as not many decades the accessibility of Construction and demolition waste has expanded so a lot of that the solid business has started using it thusly decreasing the number of totals. The goal is to examine the physical properties, (grain size distribution, density and water absorption) and mechanical properties, (for example, compressive strength, flexural strength, modulus of elasticity and splitting tensile strength) and durability properties, (for example, sulfate resistance, freezing and thawing resistance, acid resistance, high temperature effect and abrasion resistance) of recycled aggregate. It is seen that the mechanical and durability conduct of recycled aggregate concrete is optional to that of standard concrete yet with the utilizing various admixture and unique blending approach, required properties can be accomplished.

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