Influence of double hooked-end steel fibers and slag on mechanical and durability properties of high performance recycled aggregate concrete

2017 ◽  
Vol 181 ◽  
pp. 273-284 ◽  
Author(s):  
Vahid Afroughsabet ◽  
Luigi Biolzi ◽  
Togay Ozbakkaloglu
Keyword(s):  
High Performance ◽  
Recycled Aggregate Concrete ◽  
Steel Fibers ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Durability Properties

Performance Enhancement of Recycled Aggregate Concrete – An Experimental Study

2021 ◽  
Author(s):  
Sivamani Jagan ◽  
Thurvas Renganathan Neelakantan ◽  
Palaniraj Saravanakumar
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Elastic Modulus ◽  
Performance Enhancement ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Coarse Aggregates ◽  
Durability Properties ◽  
Concrete Mixtures

Extensive studies have been performed on the mechanical and durability properties of the concrete prepared with recycled coarse aggregates (RCA), however, only modest consideration has been given to the studies on the behaviour of RAC prepared by alternative mixing approach techniques. This study presents the mechanical properties of the recycled aggregate concrete (RAC) with different percentages of RCA prepared by normal mixing approach (NMA), two-stage mixing approach (TSMA) and sand enveloped mixing approach (SEMA) techniques. The manufactured concrete mixtures were tested for compression, tension, flexure and elastic modulus at 7, 28 and 90 days. The results indicate that the mechanical properties of the RAC (with 100% of RCA) prepared through TSMA and SEMA were improved by 9.36 and 12.14% at 28 days. Perhaps, prolonged curing to TSMA and SEMA mixtures improved the mechanical properties of the RAC that is nearly equal to normal aggregate concrete (NAC) prepared by NMA.

scholarly journals Sulfate Resistance of Recycled Aggregate Concrete with GGBS and Fly Ash-Based Geopolymer

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1247 ◽  
Author(s):  
Jianhe Xie ◽  
Jianbai Zhao ◽  
Junjie Wang ◽  
Chonghao Wang ◽  
Peiyan Huang ◽  
...  
Keyword(s):  
Fly Ash ◽  
Construction Projects ◽  
High Performance ◽  
High Performance Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Aggregate Concrete ◽  
Sulfate Resistance ◽  
Coarse Aggregates

There is a constant drive for the development of ultra-high-performance concrete using modern green engineering technologies. These concretes have to exhibit enhanced durability and incorporate energy-saving and environment-friendly functions. The object of this work was to develop a green concrete with an improved sulfate resistance. In this new type of concrete, recycled aggregates from construction and demolition (C&D) waste were used as coarse aggregates, and granulated blast furnace slag (GGBS) and fly ash-based geopolymer were used to totally replace the cement in concrete. This study focused on the sulfate resistance of this geopolymer recycled aggregate concrete (GRAC). A series of measurements including compression, X-ray diffraction (XRD), and scanning electron microscopy (SEM) tests were conducted to investigate the physical properties and hydration mechanisms of the GRAC after different exposure cycles in a sulfate environment. The results indicate that the GRAC with a higher content of GGBS had a lower mass loss and a higher residual compressive strength after the sulfate exposure. The proposed GRACs, showing an excellent sulfate resistance, can be used in construction projects in sulfate environments and hence can reduce the need for cement as well as the disposal of C&D wastes.

scholarly journals Experimental Characterization of Prefabricated Bridge Deck Panels Prepared with Prestressed and Sustainable Ultra-High Performance Concrete

2020 ◽  
Vol 10 (15) ◽  
pp. 5132
Author(s):  
Muhammad Naveed Zafar ◽  
Muhammad Azhar Saleem ◽  
Jun Xia ◽  
Muhammad Mazhar Saleem
Keyword(s):  
High Performance ◽  
Bridge Deck ◽  
High Performance Concrete ◽  
High Strength ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Ultra High Performance Concrete ◽  
Aggregate Concrete ◽  
Deck Panels

Enhanced quality and reduced on-site construction time are the basic features of prefabricated bridge elements and systems. Prefabricated lightweight bridge decks have already started finding their place in accelerated bridge construction (ABC). Therefore, the development of deck panels using high strength and high performance concrete has become an active area of research. Further optimization in such deck systems is possible using prestressing or replacement of raw materials with sustainable and recyclable materials. This research involves experimental evaluation of six full-depth precast prestressed high strength fiber-reinforced concrete (HSFRC) and six partial-depth sustainable ultra-high performance concrete (sUHPC) composite bridge deck panels. The composite panels comprise UHPC prepared with ground granulated blast furnace slag (GGBS) with the replacement of 30% cement content overlaid by recycled aggregate concrete made with replacement of 30% of coarse aggregates with recycled aggregates. The experimental variables for six HSFRC panels were depth, level of prestressing, and shear reinforcement. The six sUHPC panels were prepared with different shear and flexural reinforcements and sUHPC-normal/recycled aggregate concrete interface. Experimental results exhibit the promise of both systems to serve as an alternative to conventional bridge deck systems.

On Construction Wastes Recycling and its Economy

2013 ◽  
Vol 567 ◽  
pp. 119-122
Author(s):  
Yue Qin Tang
Keyword(s):  
High Performance ◽  
Drying Shrinkage ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Bleeding Rate ◽  
Aggregate Concrete ◽  
Ordinary Concrete ◽  
Easy Bleeding ◽  
Large Water ◽  
Water Absorbability

This paper addresses problems of aggregate concrete of construction wastes, which were featured as large water absorption, quick slump loss, as well as easy bleeding and low strength of concrete. A comparative analysis by experiment between recycled aggregate concrete and ordinary concrete was made on aspects of water absorbability, compressive strength, slump loss, bleeding rate, drying shrinkage and economic efficiency. It has found possible to preparing the recycled aggregate concrete of high performance through the prewetting recycled aggregate. It is concluded that construction wastes can be recycled by obtaining the optimum mole of preparing recycled aggregate concrete of construction wastes and evaluating their reliability on cost-lefficiency and mechanic capability，thus, it also recycled the limited resources and solve some environment problems.

Influence of Recycled Aggregate on Physical and Mechanical Properties of High Performance Recycled Aggregate Concrete

2011 ◽  
Vol 460-461 ◽  
pp. 764-767 ◽  
Author(s):  
Yi Dong Xu ◽  
Jia Ying Sun
Keyword(s):  
High Performance ◽  
Physical And Mechanical Properties ◽  
Chloride Ion ◽  
Poor Quality ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Ion Permeability ◽  
Negative Effects ◽  
Aggregate Concrete ◽  
Positive Effects

Influence of recycled aggregate on slump, compressive strength and chloride ion permeability of recycled aggregate concrete was investigated. As is shown by the results, although recycled aggregate belongs to the category of poor quality aggregate, the properties of high performance recycled aggregate concrete are not reduced dramatically with the increasing amount of recycled aggregate, for recycled aggregate have both positive effects and negative effects on the properties of recycled aggregate concrete. The high performance recycled aggregate concrete can be developed by double-mixture of ultra fine fly ash and superplasticizer.

Analysis of Microstructure of Interfacial Transition Zone (ITZ) in Recycled Aggregate Concrete

2013 ◽  
Vol 811 ◽  
pp. 249-253 ◽  
Author(s):  
Wei Li ◽  
Hai Ying Zhang
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Interfacial Structure ◽  
Recycled Aggregate ◽  
Concrete Aggregate ◽  
Interfacial Zone ◽  
Aggregate Concrete ◽  
Mortar Strength

Experiments on influence of species of aggregate and mixing method on interfacial zone in recycled aggregate concrete were investigated. SEM observations revealed that a recycle normal-strength concrete aggregate consist of loose and porous interfacial structure, whereas a recycled high performance concrete (HPC) aggregate and a triple mixing (TM) consist mainly of dense hydrates. Various admixtures on ITZ was produced that consumed CH in the pore, modified attached cement mortar. Strength of recycled concrete was explained by interaction between cements paste and recycled aggregate. The result verified that the relatively dense pore structure of the recycled concrete benefit to development of mechanical properties.

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