Characterization of pervious concrete with blended natural aggregate and recycled concrete aggregates

2018 ◽  
Vol 181 ◽  
pp. 155-165 ◽  
Author(s):  
Soon Poh Yap ◽  
Paul Zhao Chiat Chen ◽  
Yingxin Goh ◽  
Hussein Adebayo Ibrahim ◽  
Kim Hung Mo ◽  
...  
Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 209
Author(s):  
Adilson C. Paula Junior ◽  
Cláudia Jacinto ◽  
Thaís M. Oliveira ◽  
Antonio E. Polisseni ◽  
Fabio M. Brum ◽  
...  

The search for environmental preservation and conservation of natural resources gives rise to new concepts and viable technical solutions on the path to sustainable development. In this context, this study’s main objective is to analyse the influence of recycled concrete aggregates (RCAs) on the development of pervious concrete, whose use as a floor covering represents an excellent device to mitigate the urban soil sealing phenomena. For this, mechanical and hydraulic tests were carried out, in addition to microstructural analyses and the assessment of its environmental performance. The results obtained were compared to reference studies also involving the incorporation of recycled aggregates. A pilot-scale case study was conducted, involving a parking space lined with pervious concrete moulded “in situ”. In laboratory tests, permeability coefficients and mechanical strengths compatible with the literature and above the normative limit for light traffic were found. The case study demonstrated higher permeability than in the laboratory, but the flexural strength was lower, being indicated only for pedestrian traffic. The environmental assessment showed that the RCA represents a positive contribution to the environmental performance of pervious concrete. Still, attention should be given to the recycled aggregate transport distance between the concrete plant and the RCA treatment plant.


2011 ◽  
Vol 261-263 ◽  
pp. 446-449 ◽  
Author(s):  
Ping Hua Zhu ◽  
Xin Jie Wang ◽  
Jin Cai Feng

The influence of synchronous use of coarse and fine recycled concrete aggregates on durable performance of recycled aggregate concrete (RAC) in air environment were determined. In this study, three series of concrete mixtures were prepared, in which the coarse recycled aggregate was used as 0%, 30%, 60% and 90% replacements of coarse natural aggregate and fine recycled aggregate as 0%, 10%, 20%, and 30% replacements of fine natural aggregate. Meanwhile, fly ash and slag were used as 15%, 25%, 35% and 45% replacements of cement, respectively. The carbonation depths, compressive cube strength, workability of RACs were tested. The experimental results showed that RAC with synchronous use of coarse and fine recycled concrete aggregates had satisfactory durable performance. When RAC was used as structural concrete in air environment, the optimum synchronous replacements are 60% for coarse recycled aggregate and 20% for fine recycled aggregate.


Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 695
Author(s):  
Natt Makul ◽  
Roman Fediuk ◽  
Mugahed Amran ◽  
Abdullah M. Zeyad ◽  
Sergey Klyuev ◽  
...  

Currently, a number of disadvantages hampers the use of recycled concrete aggregates (RCA). The current review proves that concretes made with complete replacement of natural aggregate with RCA allow the production of high-quality concrete. One of the possibilities for improving concrete properties with RCA is the use of extended curing and pozzolanic materials with varying cement ratios. The potential use of RCA concretes is in the production of high-value materials that increase environmental and financial benefits. RCA have strong potential in the development of a new generation of concrete and stimulate economic activity in many countries in addition to optimizing natural resources. Economic benefits include minimal travel costs; cheaper sources of concrete than newly mined aggregates; reduction of the landfill area required for the placement of concrete waste; the use of RCA minimizes the need for gravel extraction, etc. The proposed strategy could be to sequentially separate demolition waste such as roof finishes, waterproof materials, interior and exterior materials, etc. Closing life cycles is the main approach used for efficient structures for the recycling and reuse of construction and demolition waste in the production and recovery of materials, especially when recycling and reusing materials. In the life cycle, the recycling of recovered materials allows them to be used for new construction purposes, avoiding the use of natural concrete aggregates. Government, design institutes, construction departments and project managers should be involved in the creation and use of RCA. In demolition and construction, the main players are the project owners. Their obligations, expectations and responsibilities must be properly aligned. For the past 20 years, recycled concrete aggregate from demolition and construction waste has been considered as an alternative to pure concrete in structural concrete to minimize the environmental impact of construction waste and demolition waste and the conversion of natural aggregate resources. It is now recognized that the use of RCA for the generations of concrete is a promising and very attractive technology for reducing the environmental impact of the construction sector and conserving natural resources. In the market, the selling price is not an obstacle for market applications of RCA, as there are scenarios in which their cost is lower than the cost of products made from conventional building materials. This is more of an acceptance factor in the market for recycled concrete aggregates. In this sector, the lack of identification, accreditation and uniform quality certification systems and their narrow application cause some marketing problems. With proper RCA preparation, concrete with standard physical and mechanical properties and performance characteristics can be obtained.


Proceedings ◽  
2019 ◽  
Vol 34 (1) ◽  
pp. 7 ◽  
Author(s):  
Marija Nedeljković ◽  
Jeanette Visser ◽  
Siska Valcke ◽  
Erik Schlangen

In the Netherlands, yearly 20 Mt Construction- and Demolition waste (CDW) is being produced mainly consisting of concrete and masonry rubble. This is two third of the yearly production of concrete (33 Mt). Currently, less than 1 Mt/year of the 20 Mt/year CDW is recycled in new concrete (mainly as coarse recycled concrete aggregates). This preliminary study being part of a larger study, is aiming to increase that amount, amongst others by focusing on use of the fine recycled concrete aggregates. Fine recycled concrete aggregates (fRCA) appear promising for (partial) replacement of natural fine aggregates (sand) and cement in new concrete. Nevertheless, they can be expected to have adverse properties and components that may reduce the performance of the concrete. Their physical, chemical and mechanical properties, which thus may significantly differ from that of natural sand, are still far from being fully investigated. The present paper focusses on characterization of physical properties of fRCA for finding the most critical indicators for fRCA quality. The tests include particle size distribution, morphology, BET surface area, solid density and water absorption of individual and total fractions (0–0.25 mm, 0.25–4 mm and 0–4 mm). The tests are performed on three fRCAs with different origin. Natural river sand with 96 wt.% of SiO2 was also studied to provide a baseline for comparison. Experimental results showed that, on the one side, the particle size distribution, surface area and amounts of individual fractions of fRCAs are significantly different from that of natural sand and that there is a large difference between each other. This is caused by variations of the parent concrete properties and by the type of recycling technique and processes (one step or multiple steps crushing). On the other side, fRCAs have comparative solid densities, which were still lower than that of natural sand. It was also shown that difference in water absorption between fractions 0.25–4 mm and 0–4 mm is very small in all three fRCAs groups. The results of this study will be used for future correlations between investigated properties of fRCAs with properties of concretes with fRCAs. This will be investigated in the next stage of the project, such that these correlations can enable production of durable concretes with fRCAs and assist recyclers in optimization of their production processes based on quality control of fRCAs.


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