scholarly journals Influence of Partial Coarse Fraction Substitution of Natural Aggregate by Recycled Concrete Aggregate in Hot Asphalt Mixtures

2019 ◽  
Vol 12 (1) ◽  
pp. 250 ◽  
Author(s):  
Debora Acosta Álvarez ◽  
Anadelys Alonso Aenlle ◽  
Antonio José Tenza-Abril ◽  
Salvador Ivorra

The main objective of this work is to evaluate the properties of hot asphalt mixtures that have been manufactured with different recycled concrete aggregate (RCA) percentages (0%, 20%, 40%, 60% and 80% of the fraction 5–13 mm) and asphalt (4%, 4.5% and 5%). Dense asphalt mixtures were made; partially replacing the natural aggregate (NA) fraction between 5 and 13 mm. Marshall specimens were manufactured to determine the main properties of the asphalt concrete (AC) in terms of density, voids, stability and deformation. Additionally, the optimal asphalt content (OAC) was determined, and measured the water sensibility, the stiffness modulus and the permanent deformation. The results corroborate the potential for using these sources of construction and demolition waste (CDW) as a RCA in asphalt concrete and show that the hot asphalt mixtures with up to 40% substitution of natural aggregate by recycled aggregate in the fraction 5–13 mm present good behavior.

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1976 ◽  
Author(s):  
Samuel Roque ◽  
Cinthia Maia Pederneiras ◽  
Catarina Brazão Farinha ◽  
Jorge de Brito ◽  
Rosário Veiga

This paper presents a study of incorporation of two types of construction and demolition waste (CDW) in rendering mortars, as aggregates at 0%, 20%, 50% and 100% (by volume). Recycled concrete aggregate (RCA) and mixed recycled aggregate (MRA) were used. The former is mainly composed of cementitious waste and the latter consists of a mixture of non-segregated wastes. The performance of the cement mortars with recycled aggregates was evaluated through an extensive experimental programme. The analysis comprised workability, mechanical strength, water absorption, shrinkage, open porosity and the evaluation of durability by permeability to water under pressure after an artificial accelerated ageing test. The results are considered positive, although as the incorporation of recycled aggregates (both MRA and RCA) increased the mechanical strength, the modulus of elasticity and bulk density decreased, which leads to the production of lighter mortars that are less susceptible to cracking. The modified mortar with 20% of MRA presented the best performance, in terms of mechanical behaviour.


2018 ◽  
Vol 10 (8) ◽  
pp. 2590 ◽  
Author(s):  
Debora Acosta Alvarez ◽  
Anadelys Alonso Aenlle ◽  
Antonio Tenza-Abril

Recycled Aggregates (RA) from construction and demolition waste (CDW) are a technically viable alternative to manufacture of asphalt concrete (AC). The main objective of this work is to evaluate the properties of hot asphalt mixtures that have been manufactured with different sources of CDW (material from concrete test specimens, material from the demolition of sidewalks and waste from prefabrication plants) from Cuba. Dense asphalt mixtures were manufactured with a maximum aggregate size of 19 mm, partially replacing (40%) the natural aggregate fraction measured between 5 mm and 10 mm with three types of RA from Cuba. Marshall specimens were manufactured to determine the main properties of the AC in terms of density, voids, stability and deformation. Additionally, the stiffness modulus of the AC was evaluated at 7 °C, 25 °C and 50 °C. The results corroborate the potential for using these sources of CDW from Cuba as a RA in asphalt concrete, thereby contributing an important environmental and economic benefit.


2014 ◽  
Vol 5 (2) ◽  
Author(s):  
Mirjana Malešev ◽  
Vlastimir Radonjanin ◽  
Gordana Broćeta

Following an example of the world's great powers that developed the recycling industry after natural disasters and wars, the paper points to the possibility of using large quantities of construction and demolition waste, generated as a result of the recent floods in the BiH and Serbia. Based on the years of extensive experimental research, and the research conducted by eminent experts, an overview is provided of the most basic properties and application of recycled aggregate concrete. It has been shown that the application of coarse recycled concrete aggregate, as the component materials in the concrete mixtures, it is possible to produce structural concrete that can be satisfactory and even with high quality, which primarily depends on the characteristics of crushed demolished concrete.


Author(s):  
Burcu Aytekin ◽  
Ali Mardani-Aghabaglou

In this paper, a comprehensive literature review was conducted on the utilization of recycled concrete aggregate (RCA), which is the dominant construction and demolition waste material, in base and subbase layers and its comparison with natural aggregate (NA). The effects of crushing on the particles as a result of the compaction on the resilient modulus, permanent deformation, and California Bearing Ratio are analyzed. The paper also contains the NA consumption and waste disposal policies of different countries, RCA standards, and the environmental-economic reasons for its use. This literature review mainly focuses on pavement layers as this is the main application of RCA in the use of recycled materials. Developing integrated construction and demolition waste management will help achieve the primary goal of preventing and reducing the generation of these wastes, both locally and globally. In this way, not only is the main purpose of preventing the increase in the production of construction and demolition waste achieved, but also the reuse and recycling of the waste materials produced are encouraged. Results show that RCA has equivalent or better performance than virgin aggregate for almost any application with proper care and process control, and can be used in unbound pavement layers or other applications requiring compaction. But it is always recommended that its mechanical properties and durability performance be evaluated with full-scale tests before use. The information provided will be useful for contractors and engineers to evaluate alternative solutions and to explore the rational use of such sustainable materials in applications.


2018 ◽  
Vol 196 ◽  
pp. 02018
Author(s):  
Roman Jaskulski ◽  
Marcin Supera ◽  
Wojciech Kubissa ◽  
Peter Koteš ◽  
Miroslav Brodňan

The main goal of this research was to evaluate the effects of using recycled concrete aggregate (RCA) of an average quality as a 50% replacement for natural coarse aggregate. A total of 26 concrete mixtures were prepared, 13 containing RCA as a 50% of coarse aggregate and the same number of mixes only with natural aggregate (NA). The results show the influence of the RCA incorporation on concretes for the same w/c ratio. Both mechanical and durability parameters of the concretes made with recycled aggregate are worse, and the differences increase for low w/c ratio. Despite the reduction of these parameters in relation to concretes with only NA, both mechanical and durability test results obtained for concrete series with RCA can be described as good.


2019 ◽  
Vol 22 ◽  
pp. 67-71
Author(s):  
Karel Mikulica ◽  
Iveta Hájková

In the future, it is planned to use up to 50% of construction and demolition waste (C&DW) for the production of new building structures. This leads us to think about how we can use recycled concrete aggregate (RCA) as a substitute for natural aggregate (NA) in concrete mixtures. This is why we compare the two typical representatives of recycled aggregates with a representative of natural aggregates. As a representative of recycled aggregates, we chose pure concrete recycled from the cutting of concrete and mixed recyclate from the demolition of the apartment building. As a representative of natural stone, we chose the extracted aggregate.


Author(s):  
Xijun Shi ◽  
Anol Mukhopadhyay ◽  
Dan Zollinger

To overcome the challenges associated with natural aggregate shortage and the disposal of construction and demolition waste, recycled concrete aggregate (RCA) has been increasingly used in Portland cement concrete (PCC) pavement as a virgin aggregate replacement. The work in this study involved conducting a performance evaluation of the existing RCA-PCC pavements in Oklahoma from different aspects, including: laboratory determination of mechanical properties; a petrographic examination of the concrete; a field evaluation using a falling weight deflectometer (FWD) testing; and distress surveys to assess pavement behavior. The laboratory testing of the field cores confirmed that the addition of RCA into PCC causes a reduction in the modulus of elasticity and tensile strength; the reclaimed mortar was found to be the primary weak zone through which cracks pass. The surface condition survey data and analysis of the FWD results match each other, indicating that the RCA joined plain concrete pavement (JPCP) section exhibited lower performance compared with the control JPCP section. But this trend was not as definitive for continuously reinforced concrete pavement (CRCP). The relatively good performance of the RCA CRCP results from the section being rested on a stronger asphalt concrete base layer. Additionally, the inherent stiffness fundamental to the behavior of CRCP provides a superior level of protection of the base from erosion damage compared with a jointed pavement. The findings indicate that erosion-resistant base support and good load transfer are essential design considerations for JPCP made of RCA-PCC. CRCP appears to be more suitable for the use of RCA-PCC.


In recent years, sustainable construction materials are highly recommended in construction projects due to reduce the degradation of natural resources. An experimental investigation with varying percentages of coarse recycled concrete aggregate was conducted on self-compacting concrete. The primary goal was to explore the suitability and impact of coarse recycled aggregate in concrete fresh generation. The demand for building products has risen tremendously in latest years, so the quantity of building and demolition waste has increased, placing enormous stress to the atmosphere. The use of recycled aggregate in concrete is a suitable solution to extend the lifetime of natural resources and thereby lead to sustainable developments in construction field. In this investigation, SCC is modified by recycled coarse aggregate (RCA) in various percentages of natural coarse aggregate (NCA) substitutes from 0 percent to 100 percent with a 20 percent increase. Durability and the mechanical properties of modified SCC was determined. From the results it is revealed that the substitution of RCA in the place of NCA significantly improved the durability properties.


2016 ◽  
Vol 9 (1) ◽  
pp. 75-89 ◽  
Author(s):  
L. M. TAVARES ◽  
C. S. KAZMIERCZAK

The expansion of urban areas under constant changes in the hydrological cycle directly affects the drainage of rainwater. The problems of urban drainage become major engineering problems to be solved in order to avoid negative consequences for local populations. Another urban problem is the excessive production of construction and demolition waste (CDW), in which , even with a increasingly policy of waste management , have been an end up being thrown in inappropriate disposal sites. Alternatively aiming to a minimization of the problems presented, we propose the study of permeable concrete using recycled concrete aggregate. In this study, there were evaluated the performance of concrete by means of permeability, consistency, strength, and interface conditions of the materials . Satisfactory relationships of resistance/permeability of concrete with recycled aggregate in relation to the concrete with natural aggregates was obtained, showing their best potential.


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