Effects of North Carolina Recycled Aggregates on the Mechanical Properties of Concrete
Author : Danial G. Fisher
Publisher :
Page : 188 pages
File Size : 23,70 MB
Release : 1996
Category :
ISBN :
Author : Danial G. Fisher
Publisher :
Page : 188 pages
File Size : 23,70 MB
Release : 1996
Category :
ISBN :
Author : Shuaib Haroon Ahmad
Publisher :
Page : 108 pages
File Size : 48,36 MB
Release : 1996
Category : Aggregates (Building materials)
ISBN :
In this study, recycled coarse and fine aggregates were obtained from a portion of concrete pavement which was removed from Interstate 40 in North Carolina. Various amounts of recycled coarse and fine aggregates were volumetrically substituted for natural coarse and fine aggregates of a control mixture. The effects on plastic and hardened concrete properties were investigated.
Author : Tannous Touma
Publisher :
Page : 37 pages
File Size : 13,69 MB
Release : 2015
Category : Aggregates (Building materials)
ISBN :
Author : Cory J. Shorkey
Publisher :
Page : pages
File Size : 38,68 MB
Release : 2010
Category :
ISBN :
Author : K. Sakai
Publisher : CRC Press
Page : pages
File Size : 21,73 MB
Release : 2014-04-21
Category : Architecture
ISBN : 1482294982
The two themes of integration of structural and durability design, and integration of concrete technologies in relation to global environmental issues are drawn together in this book. It presents the views of distinguished international researchers and engineers on these key topics as the 21st century approaches. Derived from a workshop on rational
Author : Shuaib Haroon Ahmad
Publisher :
Page : 108 pages
File Size : 38,84 MB
Release : 1996
Category : Aggregates (Building materials)
ISBN :
In this study, recycled coarse and fine aggregates were obtained from a portion of concrete pavement which was removed from Interstate 40 in North Carolina. Various amounts of recycled coarse and fine aggregates were volumetrically substituted for natural coarse and fine aggregates of a control mixture. The effects on plastic and hardened concrete properties were investigated.
Author : Andreu Gonzàlez Corominas
Publisher :
Page : 229 pages
File Size : 38,63 MB
Release : 2016
Category :
ISBN :
In recent decades, the use of High Performance Concrete (HPC) has grown vastly, being used in multiple applications with high requirements. However, the use of recycled aggregates (RA) has been mostly limited to conventional concrete. Many studies have defined limiting properties of RA, replacement ratios of natural aggregates and particular techniques to achieve suitable conventional concrete containing RA. Nonetheless, very few studies have been focused on the use of RA in the production of HPC. This study examines the behaviour of High Performance Recycled Aggregate Concrete (HPRAC) in physical, mechanical, durability and structural properties according to the RA content and its quality. RA were sourced from Construction and Demolition Waste of several categories: Recycled Concrete Aggregate (RCA) obtained from 40, 60 and 100 MPa concretes, Ceramic Waste Aggregates (CWA) and Recycled Mixed Aggregates (RMA). In the first experimental phase, the limiting replacement ratios of RA were established in order to achieve comparable HPRAC to the reference HPC with a design strength of 100 MPa. The physical, mechanical and durability properties were studied for concretes containing 20, 50 and 100% of coarse RCA and RMA, and 15 and 30% of fine CWA. According to the mechanical properties, 100% of coarse RCA can be used, as long as RA is sourced from a 60 MPa minimum-strength concrete waste. Nevertheless, durability behaviour was more influenced by the use of RA and replacement ratios of RCA could only be maintained on those obtained from parent concretes with the same quality as the new HPC. Moreover, significant reductions of the RA quality (RCA sourced from 40MPa - strength concretes or RMA) only permitted 20% replacement ratios. On the other hand, the concretes containing fine CWA (up to 30%) reached higher performances than those from conventional HPC. On the second experimental phase, fly ash was used in replacement of 30% of Portland cement in order to enhance the RCA performance. Keeping in mind prestressed concrete as potential application which requires high early-age strength, the concrete mixtures were also subjected to an initial steam curing cycle. The natural aggregates could be completely replaced by RCA sourced from the same quality HPC, producing improved mechanical properties and pore structures. It was determined that when using lower quality aggregates, the use of steam curing was mandatory to fulfil the standard requirements for prestressed concrete. The steam curing had negative effects on the long-term mechanical properties, however the steam-cured HPRAC had greater improvements on the pore structure and the mechanical properties than conventional HPC. The third experimental phase assesses the role of RCA in internal curing whose effect is significant in HPC. The effects of RCA were investigated in the plastic, autogenous and drying shrinkage of HPC, being the second of special interest in concretes with low water-cement ratio. The results revealed that the plastic and drying shrinkage became higher as the quality of the RCA decreased and the replacement ratio increased. However, a reduction in the autogenous shrinkage was proved to be possible by the use of a high content of lower quality RCA, since they acted as internal curing agents. The suitable behaviour of the HPRAC mixtures containing 50 and 100% of RCA sourced from 100 MPa-strength concretes enabled the production of prestressed concrete sleepers. The structural properties of HPRAC were tested on the conventional HPC and on both HPRAC sleepers. The prestressed concrete sleepers were subjected to static and dynamic load tests at rail-seat and centre sections. The structural requirements for prestressed concrete sleepers were extensively verified by sleepers made with HPRAC. Regardless of the replacement ratio, the HPRAC sleepers' results barely differed from those of conventional HPC sleepers.
Author : Jorge de Brito
Publisher : MDPI
Page : 280 pages
File Size : 30,11 MB
Release : 2019-07-15
Category : Technology & Engineering
ISBN : 3039211404
This book is the result of a Special Issue published in Applied Sciences, entitled “New Trends in Recycled Aggregate Concrete". It identifies emerging research areas within the field of recycled aggregate concrete and contributes to the increased use of this eco-efficient material. Its contents are organised in the following sections: Upscaling the use of recycled aggregate concrete in structural design; Large scale applications of recycled aggregate concrete; Long-term behaviour of recycled aggregate concrete; Performance of recycled aggregate concrete in very aggressive environments; Reliability of recycled aggregate concrete structures; Life cycle assessment of recycled aggregate concrete; New applications of recycled aggregate concrete.
Author : Mohd Khairul Ikhwan Abd Raof
Publisher :
Page : 85 pages
File Size : 40,46 MB
Release : 2009
Category : Concrete
ISBN :
Author : Sajjad Ali Khan
Publisher :
Page : 320 pages
File Size : 36,75 MB
Release : 2005
Category : Aggregates (Building materials)
ISBN :