Papers by Keyword: Demolition Waste

Abstract: Annually, billions of metric tonnes of solid waste are produced, including Polyethylene Terephthalate (PET) plastic waste and other industrial manufacturing by-products. This study assesses durability of waste plastic bricks (WPB), which are made by repurposing scrap plastics from PET. Mechanical and fire resistance properties of WPB have been optimised by varying mixing proportions of PET plastic and mixtures of industrial waste materials like fly ash, waste glass powder and concrete debris in ratios of (20:80, 30:70 and 40:60) respectively. This investigation integrates various wastes synergistically to produce bricks, aiming to replace traditional bricks made from cement and clay. This study investigates mechanical and physical properties of interlocking blocks made from mixtures of plastic and industrial waste materials, including fly ash, waste glass powder, and concrete debris. A mixture ratio of 20:80 (plastic to waste materials) yields a compressive strength of 27.3 N/mm², suitable for use in partition walls. Water absorption rates decrease significantly from 3.5% in conventional blocks to 0.5% in 20:80 ratio blocks, with further reductions to 0.43% and 0.40% for 30:70 and 40:60 ratios, respectively, enhancing water resistance. Efflorescence tests indicate improved performance in blocks with higher proportions of alternative materials, meeting highest standards for first-class bricks. Fire resistance tests confirm that all block compositions, including conventional and mixed ratio blocks, achieve a one-hour fire resistance duration, compliant with ASTM E119 standards, ensuring durability and safety of these alternative material blocks.

Abstract: Since the inception of self-compacting concrete, there has been a growing interest in integrating waste materials into its composition. This study explores the performance of self-compacting concrete and fibered self-compacting concrete, incorporating recycled aggregates sourced from the demolition and crushing of previously tested specimens. Additionally, it investigates the influence of steel fibers, both of commercial origin and those recycled from waste tires. The analysis spans both the fresh and hardened states, encompassing twelve concrete mixtures to assess workability (through measurements such as slump flow, T500, and L-BOX), segregation resistance, compressive strength, and flexural strength. Furthermore, the durability of these concrete mixtures is evaluated by examining mass loss and compressive strength after 56 days of exposure to acidic environments (HCl and H₂SO₄). The study is organized into three distinct series of concrete mixtures. The first series explores concrete without any fiber additives, focusing on replacing filler limestone with recycled concrete powder and/or substituting coarse aggregates with recycled concrete aggregates. In the second series, commercial fibers are introduced at a dosage of 30 kg/m³. The third series replaces the commercial fibers with recycled fibers with hooked ends. The assessment of the hardened state reveals enhanced mechanical properties in the case of fibered self-compacting concrete (compressive strength increased by more than 9%, and flexural strength increased by more than 8%). Notably, the results highlight that recycled aggregates exhibit improved resistance to HCl acid attack. Interestingly, the replacement of commercial fibers with recycled fibers does not substantially affect the concrete's resistance to acid exposure.

Abstract: Construction and demolition waste (CDW) is very high in quantity, 30% - 40% of total solid waste and their management is inadequate and lack the integration of sustainability concepts. This situation leads to severe environmental effects, which are mainly associated with the production of new building materials due to the low recovery rate. In fact some studies show that 5-10% of total energy consumption across the EU is related to the manufacture of construction products. For this reason, CDW is a priority for many policies globally. For several years, a growing trend towards more sustainable construction processes has been taking place with a focus on secondary raw materials with lower environmental impacts on the entire life cycle. For this reason, this paper intends to contribute to increasing knowledge in this field through a review article. The review has the aim to evaluate the research gap, strategies to reduce construction waste and to promote the recycled materials use for a circular economy in construction sector. The results of the study showed that interest in this field of research has grown strongly over the years: the most publications on the subject relate to the last five years. On the other hand, issues relating to the topic did not attract particular interest in the range 2010-2016, in fact the number of publications in this period did not exceed 4%. The research showed that Europe is among the communities most sensitive to the issue and it has clearly revealed that there are still many barriers and research gaps to be overcome on this issue and the study has tried to identify the main ones.

Abstract: The recycling of construction and demolition waste (CDW) is currently of growing interest. Starting from such waste products it’s possible to produce recycled aggregates for construction purposes providing environmental and economic advantages. Life-cycle assessment (LCA) is a valuable tool to evaluate the environmental impact at end of life of CDW and improve the employment of recycled aggregates in concrete. In this research a life cycle evaluation of concrete mixtures made with CDW is performed to assess their environmental impacts considering various scenarios related to recycling sites with different conveying distances. The advantages of replacing natural aggregates with recycled ones are evaluated using a combination of LCA model and Life-Cycle Impact Assessment to estimate the environmental effects for all the considered scenarios. The results highlighted the highest environmental impact for the scenario with total landfill as well as an increasing impact for increasing distance from the demolition site.

Abstract: The present research has been conducted to trace the various effects of Mosul city demolition waste materials (DMs), on the geotechnical properties of clay. The properties of the samples have already been investigated and evaluated. Moreover, cement has been added to upgrade these properties. Finally, the fine demolition has been added to a highly expansive soil selected from the site of the University of Mosul to reduce the swelling potential. In fact, the experimental work includes: The Abrasion, index and compaction properties, swelling and strength of stabilized and treated expansive soil. The laboratory tests include the testing of consistency limits, unconfined compressive strength (UCS), compaction (standard and modified), swelling, consolidation, and Abrasion test by Los Angeles Machine. The Results show that, increasing the old and new demolition (OD and ND) percentages lead to a decrease of liquid limit and plasticity index of clay, respectively. The increase in maximum γ_dry for the clay has been noticed when the OD and ND content has been added from 5 to 25%. A reduction of optimum water content (opt) for clay was optimized also by increasing the demolitions percentage to 25%. Also, the UCS strength values of the clay have been increased by increasing the demolition materials (DMs) percentage from 5 to 25%. The odometer characteristics, including the swelling and consolidation of DMs-clay mixtures, were controlled mainly by the type of the demolition. The final result indicates that the presence of old and new demolition waste could improve the clay engineering properties of the stabilized soil. Untreated and cement treated (OD) and (ND) materials could be successfully used as a base or sub-base for road.

Abstract: The present study investigates waste generation during the production and erection phase of a prefabricated single family house in Austria as a basis for identifying waste prevention potentials. Therefore, the material composition of a case study building (wood frame construction) is compared to waste generated during production and erection. In order to assess the whole life cycle of prefabricated buildings the use phase as well as the end-of-life phase are also considered. Examples are given to show how different measures can impact the generation of waste directly and indirectly. The results show that production and erection are already very efficient with regard to waste generation and prevention potentials mainly exist in further offcut reduction and optimization in packaging. The use phase and the end-of-life of the building are more complex to investigate and waste prevention potentials are less tangible. However, important measures for waste reduction are related to the easy exchangeability of building components as well as their reusability. The lifetime extension of the building and building components, which can be achieved through proper operation and maintenance, can be considered a key issue for preventing waste in the building sector.

Abstract: The main aim of this contribution is comparison the properties of fine aggregate concrete with partial replacement of sand by fine recycled aggregate. The fine recycled aggregate originated from two different sources. The main topic of this article is the study of influence of the origin of FRA to fine aggregate concrete properties. The compressive strength, flexural strength and freeze-thaw resistance were tested. The mechanical properties and weight were examined after 28 and 60 days and after 25, 50, 75 and 100 cycles of freeze-thaw. Partial replacement of sand was 25 and 50 % for all these tests. The properties were investigated by using prismatic specimens.

Abstract: Due to the increasing concern about the environment and depleting conventional materials, a lot of research is going on in the field of material science to develop environment friendly materials, and to improve the recycling and reusing of waste materials. Composites are material providing possibilities to reach these targets. In this experimental study, the possibilities and potential in the utilization of mixed waste from recycling in the manufacturing of epoxy composites are studied. The studied properties are flexural properties, i.e. flexural strength and flexural modulus, and hardness as mechanical properties, and water absorption and thickness swelling as physical properties. Element analysis was used to determine the composition of construction and demolition waste used in manufacturing. The analysis revealed a large proportion of mineral elements with high hardness. Consequently, this had a clear impact on the hardness of the composite. The flexural properties were found to be on a reasonable level. The waste-epoxy composite showed a low uptake of water due to the minor content of hydrophilic materials present in the composite.

Abstract: The main aim of this contribution is verification of durability properties of concrete with partial replacement of cement by recycled cement powder (RCP) sourced from pure waste concrete. The main topic of this article is the study of influence of partial replacement of cement by RCP to the carbonation resistance of fine aggregate concrete with partial replacement of cement. The compressive strength, tensile strength in bending and depth of carbonation were tested after 56 days of CO² curing. Partial replacement of cement was 0, 5, 10 and 15 % for all these tests. The properties were investigated by using prismatic specimens.

Abstract: This investigation is focused on possibility of partial cement replacement in concrete mixture and its environmental assessment. The cement in concrete mixture is replaced by recycled cement powder from modified construction and demolition (C&D) waste. Recycled cement powder were prepared in laboratory from C&D waste of high quality road concrete. The main goal of this investigation is optimize amount of recycled cement powder used as partial replacement of cement in concrete mixture according to mechanical, deformation and physical properties of concrete and environmental impact. The properties of the fine-aggregate concrete with partial replacement of cement by recycled cement powder were tested for this verification. The life cycle analysis was calculated for this optimization. The properties and environmental assessment of the fine-aggregate concrete with partial replacement of fine aggregate by fine recycled aggregate were examined for comparison.