Optimization of normal and high strength recycled aggregate concrete mixtures by using packing model

2017 ◽  
Vol 84 ◽  
pp. 83-92 ◽  
Author(s):  
Mayara Amario ◽  
Caroline Santana Rangel ◽  
Marco Pepe ◽  
Romildo Dias Toledo Filho
Keyword(s):  
High Strength ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Concrete Mixtures ◽  
Packing Model

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 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.

Durable Performance of Recycled Concrete Using Coarse and Fine Recycled Concrete Aggregates in Air Environment

2011 ◽  
Vol 261-263 ◽  
pp. 446-449 ◽  
Author(s):  
Ping Hua Zhu ◽  
Xin Jie Wang ◽  
Jin Cai Feng
Keyword(s):  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Structural Concrete ◽  
Aggregate Concrete ◽  
Cube Strength ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Natural Aggregate ◽  
Concrete Mixtures

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.

Carbonation Behavior of Recycled Aggregate Concrete under Loading

2011 ◽  
Vol 250-253 ◽  
pp. 779-782 ◽  
Author(s):  
Ping Hua Zhu ◽  
Xin Jie Wang ◽  
Jin Cai Feng
Keyword(s):  
Fly Ash ◽  
Detrimental Effect ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Loading Level ◽  
Natural Aggregate ◽  
Concrete Mixtures ◽  
Carbonation Resistance ◽  
Negative Effect

A study on carbonation resistance of recycled aggregate concrete (RAC) subjected to different loading level was carried out. Three series of concrete mixtures were prepared with loading level of 0.5, 0.8, and 1.2 of ultimately tensive strength of concrete. The coarse recycled aggregate was used as 30%, 60% and 90% replacements of coarse natural aggregate and fine recycled aggregate as 10%, 20%, and 30% replacements of fine natural aggregate. Moreover, the fly ash and slag were employed as 15%, 25%, and 35% addition of cement. Although the action of the tensile stress had a negative effect on the carbonation resistance of RAC, it was found that the addition of fly ash and slag was able to mitigate this detrimental effect. The carbonation depth would increase with an increasing loading level and reduce when increasing the sand ratio.

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