通过关键词查论文: Demolition Waste

文章题目页数

作者: Tereza Pavlů, Magdaléna Šefflová
摘要: 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.
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作者: Martina Draganovska, Alena Sicakova
摘要: Today’s world trend in construction and development of building materials is focused to research and development of material systems with properties resulting from dimensions of the components in the micro and nanoscale. Improved mechanical and physical properties, better durability as well as environmental and economic benefits are expected. Such of improved materials represent significant benefit for sustainable construction. In current world, construction and demolitions waste (C&DW) represents useful source of secondary raw materials for production of new building materials. This paper is engaged to assessment of impact the fine particles obtained by grinding of C&DW to technological and physico-mechanical parameters of mortar. Two types of different C&DW which vary in strength and microstructure were used for the experiment: glass and clay bricks. For the assessment of the properties of mortars with application of those ultrafine materials as filler, recipes with 20 and 60% replacement of natural fine aggregate were prepared and tested. Water demand for specified consistency was tested in the fresh state of mortars, while flexural, compressive and adhesive strength was tested after 2, 7, and 28 days of setting and hardening. Given results show positive or negligibly impaired impact of fine grain modification of glass and clay brick on tested parameters.
81
作者: Tereza Pavlů, Vladimír Kočí, Magdaléna Šefflová
摘要: 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.
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作者: Tereza Pavlů
摘要: 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.
176
作者: Tereza Pavlů, Magdaléna Šefflová
摘要: This investigation was focused on possibility of use recycled cement powder originating from the construction and demolition concrete waste as partial replacement of cement in concrete mixture. The main goal of this paper is the study of the mechanical properties development of the fine-aggregate concrete with partial cement replacement at the age 7, 14 and 28 days. The compressive strength and dynamic modulus of elasticity were tested in time. The recycled cement powder from fine recycled concrete, which was used as partial replacement of cement, had the same grain size as cement. The concrete mixtures contained 95 %, 90 % and 85 % of cement and residue has been replaced by recycled cement powder. Mechanical properties were tested on cubic and prismatic specimens.
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作者: Marko Hyvärinen, Timo Kärki
摘要: 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.
9
作者: Winnie Franco Santos, Marco Quattrone, Sergio Cirelli Angulo
摘要: This study aims to investigate the properties of CDW recycled aggregates using silane-based water repellent agent in three different types of treatments: (a) immersion; (b) sprinkling; and (c) dripping; in order to improve the reduces quality of the material due to the high porosity. Wettability and water absorption were determined by apparent contact angle measurements, water absorption after 24h of saturation (standard method) and recording the variation of submerged mass during 24 hs. All treatment allowed reducing the water absorption and its kinetic. The contact angle measurements confirmed the effectiveness of the treatment: the surface resulted always hydrophobic. Comparing the treatments, immersion gave the best result in terms of absolute results and in terms of variability of measurements.
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