Use Of Alternative Aggregates In Pavement Concrete: Research And Practice In Belgium

2021 ◽  
Author(s):  
Elia Boonen ◽  
Slyvie Smets ◽  
Audrey Van der Wielen

Alternative aggregates, including recycled (concrete) aggregates as well as artificial aggregates (such as crushed stainless steel slag), are being increasingly used in road construction in the context of a more circular economy, e.g. in base and subbase layers. As these materials are applied higher up in the structure (surface and binder courses), stricter requirements are made to allow for higher loads and the stronger influence of the environment, and the application of these aggregates becomes less straightforward. The Belgian standard specifications, for instance, allow incorporation of recycled concrete aggregates in concrete pavements or linear elements in concrete, but only if certain stringent requirements are met and only up to certain percentages of substitution of the natural coarse aggregates. Furthermore, artificial aggregates originating from stainless steel slag are not even allowed for the time being in pavement quality concrete, although a Belgian standardization working group has recently been installed to investigate this matter in more detail. This paper presents an overview of laboratory research conducted in Belgium to characterize several types of alternative aggregates and concrete mixtures incorporating them, while focusing on practical execution as well as on the durability of pavement concrete. In addition, several concomitant pilot applications in Belgium are discussed in view of future perspectives for the application of alternative (recycled and/or artificial) aggregates in road construction.

2018 ◽  
Vol 30 (4) ◽  
pp. 04018046 ◽  
Author(s):  
Teerasak Yaowarat ◽  
Suksun Horpibulsuk ◽  
Arul Arulrajah ◽  
Mehdi Mirzababaei ◽  
Ahmad Safuan A Rashid

2018 ◽  
Vol 206 ◽  
pp. 02004 ◽  
Author(s):  
X Wang ◽  
C S Chin ◽  
J Xia

Recycled concrete aggregates have been widely studied and used in concrete products nowadays. However, other recycled wastes, such as glass, have not been involved too much in recycled aggregate concrete studies. This paper aims to study the impact of the content variation of the different recycled wastes to the properties of the concrete paving block. In this paper, not only recycled coarse concrete aggregates, crushed glass are also used as the recycled aggregate in the concrete paving block in different replacement levels. According to test the properties of blocks mixed with different recycled wastes, the experimental results indicate that: (1) adding recycled concrete coarse aggregate (RCCA) in the blocks can decrease the blocks’ strength, and increase the water absorption. The suggested replacement levels for RCCA is 60%; (2) mixing crushed glass (CG) in the concrete paving blocks as a type of coarse aggregates can obviously improve the blocks’ strength and decrease the blocks’ water absorption.


2020 ◽  
Vol 19 (1) ◽  
pp. 107-120
Author(s):  
Martinus Pramanata Sapeai ◽  
Johannes Adhijoso Tjondro

Utilization of recycled concrete waste as an alternative to natural coarse aggregates in this experiment is in accordance with the concept of sustainable construction. Concrete is the main material of structural elements most commonly used in general construction and has properties that are difficult to recycle by themselves naturally. Nowdays concrete innovation with the concept of self compacting (SCC) is widely used especially in high rise building and buildings with special specification. SCC has high flowability properties so that it can flow and compact themselves, but in SCC with normal quality still need compactor. The concept of making test specimens is in accordance with real conditions in the field, where aggregates do not go through a cleaning process. There are four different mix design with the required specified compressive strength of 20 MPa. Mix design 1A (natural coarse) and 1B (recycled coarse aggregates) has a maximum aggregate size 12.50 mm, and mix design 2A (natural coarse) and 2B (recycled coarse aggregates) has a maximum aggregate size 19.00 mm. This experimental results in specified compressive strength concrete for mix design 1A, 1B, 2A, and 2B as follows: 30.93 MPa, 26.21 MPa, 30.82 MPa and 27.60 MPa. Therefore, recycled concrete aggregates can be alternative to natural coarse aggregates and can also be made into concrete with the SCC concept.


2018 ◽  
Vol 10 (9) ◽  
pp. 3036 ◽  
Author(s):  
Viviana Letelier ◽  
José Ortega ◽  
Ester Tarela ◽  
Pedro Muñoz ◽  
Bastián Henríquez-Jara ◽  
...  

At present, reducing the environmental impact of the construction industry is a major subject of study. In terms of the use of recycled concrete aggregates (RCA), most recently conducted studies have shown that the use of a limited percentage of those aggregates does not significantly affect the properties of concretes. This work analysed the mechanical properties of medium-strength concretes with a high contribution to sustainability, where cement and natural coarse aggregates (NCA) were partially replaced by volcanic powder (VP) and RCA, respectively. Three mixing ratios of VP replacement were tested in concretes without RCA and concretes with 30% RCA replacing NCA. Results show that when VP is used without RCA, up to 10% of the cement can be replaced by VP without a significant loss in the mechanical properties. When a combination of 5% VP and 30% RCA is used, the weakness of the recycled concrete is strengthened, obtaining stronger concretes than a control concrete with no recycled materials. Finally, the greenhouse gas assessment showed that the simultaneous incorporation of VP and RCA reduces CO2 emissions produced in the manufacture of concrete by up to 13.6%.


2019 ◽  
Vol 271 ◽  
pp. 02003
Author(s):  
Daniel Odion ◽  
Mohammed J Khattak ◽  
Makarios Abader ◽  
Nathan Heim

The recycling of concrete aggregates has become a viable venture to investigate particularly its application in road construction. This study was conducted to proffer the feasibility of using recycled concrete aggregate (RCA) mixed with soil, flyash and alkali activator as an alternative to soil-cement in road base or subbase applications. The resulting product known as Soil-RCA geopolymer was made by varied mix constituents of flyash, RCA, sodium silicate, and sodium hydroxide. The influence of mixture variables on the mechanical properties of Soil-RCA geopolymer was investigated through an experiment design using two different flyash. Models to predict the unconfined compressive strengths based on mixture parameters were also established for the sensitivity analysis and selection of final mixtures. The results and analysis showed that the Soil-RCA geopolymer mixture exhibited sound strength, stiffness and durability characteristics.


2016 ◽  
Vol 12 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Ion Robu ◽  
Claudiu Mazilu ◽  
Radu Deju

Abstract Using recycled concrete aggregates (RCA) is a matter of high priority in the construction industry worldwide. In countries like the Netherlands, Denmark, Germany, USA, Japan, France recycled concrete aggregates obtained from demolition are valorized up to 90%, mainly for road construction and less in the manufacture of new concrete. Recycled concrete aggregates (RCA) generally result from a two-stage crushing of the concrete obtained from demolition followed by the screening and removal of contaminants (wood, plastic, metal, ceramics etc.). The literature review showed that the recycled aggregates concrete (RAC) are less resistant, with 15 to 40% versus concrete obtained using natural aggregates. The factors that play a role in the reducing of mechanical resistance are presented and analyzed in this study. This paper presents a study on the use of recycled aggregates, from a concrete of specified class, to acquire new cement concrete with different percentages of recycled aggregates. In order to evaluate the influence upon the properties of the new concrete obtained, recycled aggregates have been characterized in terms of the granulosity, the granule shape, the absorption of water, behavior to the Los Angeles test, the content of attached mortar etc.


Author(s):  
Anjana S ◽  
Diya Elizabeth Isaac ◽  
Neelanjana S ◽  
Aswathy G

The unprecedented increase in construction and developmental activities in the current era brings with it many irreversible impacts on the environment. The major impacts being the depletion of natural resources and generation of an enormous quantity of Construction and Demolition (C&D) wastes. Hence it has become important to reuse and recycle C & D wastes generated. These wastes can be processed to obtain Recycled Concrete Aggregates (RCA), which can be used for producing recycled concrete. It was found that the strength of Recycled concrete matches with that of paver quality concrete. Therefore, the study aims at producing interlocking paver blocks by replacing the normal coarse aggregates in pavers by RCA along with fly ash as admixture, an industrial waste. Fly ash being a pozzolanic admixture is used in order to overcome the loss of strength due to the addition of RCA. In the present study, a 30% replacement of normal aggregates with RCA and 15% replacement of cement with fly ash in the mix was used as it was found to provide the optimum strength. A comparison of the important properties of paver blocks were conducted between normal concrete pavers, pavers with RCA replacement and pavers with RCA replacement and fly ash. It was found out from the study that Interlocking pavers with partial replacement of normal aggregates with RCA and fly ash obtained strength comparable to that of normal paver blocks. Hence these paver blocks can be used for laying of roads and can contribute towards a sustainable development.


This paper discusses the effects of recycled concrete aggregates (RCA) on compressive strength and permeability of recycled aggregate concrete (RAC) by using recycled concrete aggregates as a replacement of natural coarse aggregates (NCA). Four replacement percentages were used to study the effect of replacement. Replacement percentages used were 30%, 50%, 70% and 100% with 0% replacement was used as control. Mix design of 1:1.24:2.6 was used in the study with water to cement ratio of 0.43. Influence of RCA on compressive strength was determined for all the mixes as per ASTM C39 standard. The permeability of all the mixes was determined by measuring absorption, sorptivity and Darcy’s coefficient. Results of compressive strength indicated that concrete with 30% replacement of NCA can be successfully used in structural concrete without compromising too much on strength. Whereas, the replacement of natural aggregates with RCA has a negative impact on the permeability of concrete at all replacement levels. Absorption, sorptivity and permeability of natural aggregate concrete is lower as compared to RAC with 30% replacement showing the better performance as compared to other replacement ratios.


Sign in / Sign up

Export Citation Format

Share Document