Use of Coarse Recycled Concrete Aggregate in Ternary Blended Portland Cement Concrete

Author(s):  
Seth Wagner ◽  
Gabrielle Wickizer ◽  
Douglas Cleary ◽  
Gilson R. Lomboy ◽  
Danielle Kennedy ◽  
...  

The purposes of this study were to (a) investigate concrete pavement mixtures with recycled concrete aggregates using ternary blended cementitious binders, (b) measure the fresh and hardened properties of the concrete mixtures, and (c) assess the durability of concrete implementing the use of recycled coarse aggregates with ternary binders. Mixtures had recycled concrete aggregates at varying replacement rates. The binders were combinations of Portland cement, Class C and F fly ashes, and ground granulated blast furnace slag. At 50% replacement of virgin aggregates, some specimens showed comparable mechanical performance to the control mix. Performance is heavily tied to quality of recycled aggregates. The combined use of fly ash and blast furnace slag showed improvements in results for drying shrinkage, freeze–thaw durability, resistivity, and alkali–silica reaction mitigation.

2015 ◽  
Vol 1100 ◽  
pp. 197-201 ◽  
Author(s):  
Jozef Junak ◽  
Nadežda Števulová

<p class="TTPAbstract">This contribution is focused on re-use of different types of industrial raw-wastes in concrete production. From examined wastes, blast-furnace slag and washed recycled concrete were prepared our tested concrete samples with dimension 150 mm. In these samples were fraction 0-4 mm replacement by blast-furnace slag with a range of variation from 0 to 100%. Fraction 4-8 mm and 8-16 mm were replacement by aggregate prepared from washed recycled concrete parts with a range of variation from 0 to 100% in both fractions. Concrete samples contained aggregate prepared form recycled concrete and blast-furnace slag, are tested after 14 and 28 days of hardening.</p> <p class="TTPAbstract">The highest value of compressive strength after 14 days (25.2 MPa) and 28 days of hardening (32.3 MPa) reached sample, which contained 20% of blast furnace slag as a substitute for natural aggregate in fraction 0/4 mm. Compressive strength of this sample is the same kind of reached a comparative sample. Lowest value of compressive strength after 14 and 28 days of hardening reached a sample, which contained 30% blast-furnace slag fraction 0-4 mm, and 100% aggregate prepared from recycled concrete fraction 4-8 and 8-16 mm. Before wider using of these selected wastes, another properties as a durability and corrosion are necessary to investigate.</p>


2021 ◽  
Author(s):  
Gilson Lomboy ◽  
Douglas Cleary ◽  
Seth Wagner ◽  
Yusef Mehta ◽  
Danielle Kennedy ◽  
...  

Dwindling supplies of natural concrete aggregates, the cost of landfilling construction waste, and interest in sustainable design have increased the demand for recycled concrete aggregates (RCA) in new portland cement concrete mixtures. RCA repurposes waste material to provide useful ingredients for new construction applications. However, RCA can reduce the performance of the concrete. This study investigated the effectiveness of ternary blended binders, mixtures containing portland cement and two different supplementary cementitious materials, at mitigating performance losses of concrete mixtures with RCA materials. Concrete mixtures with different ternary binder combinations were batched with four recycled concrete aggregate materials. For the materials used, the study found that a blend of portland cement, Class C fly ash, and blast furnace slag produced the highest strength of ternary binder. At 50% replacement of virgin aggregates and ternary blended binder, some specimens showed comparable mechanical performance to a control mix of only portland cement as a binder and no RCA substitution. This study demonstrates that even at 50% RCA replacement, using the appropriate ternary binder can create a concrete mixture that performs similarly to a plain portland cement concrete without RCA, with the added benefit of being environmentally beneficial.


Author(s):  
Cinthia Maia Pederneiras

The construction industry is considered the biggest waste producer in Europe. In order to encourage recycling, European Parliament decreed through the Waste Framework Directive 2008/98/EC, that at least 70% of construction and demolition waste should be recycled by 2020. From recycling plants, three types of recycled aggregates are produced. Recycled Concrete Aggregate, mainly from cementitious waste, as such as concrete and mortars residues; Recycled Masonry Aggregates mainly composed by recycled ceramic materials, as such as tiles and bricks residues; Mixed Recycled Aggregates based on rubble residues, from heterogenous materials waste. This research evaluated the technical feasibility of rendering mortars with Recycled Concrete Aggregates and Mixed Recycled Aggregates, in different volume incorporation of 0%, 20%, 50% and 100%. The experimental programme comprised an analyse of the fresh and hardened properties, regarding the water and mechanical behaviour of the mortars. From the results, it was noticed that the modified mortars presented a reduction in the modulus of elasticity, which its correlated to a less susceptibility to cracking. Regarding mechanical performance, the modified mortars obtained reduction of the flexural and compressive strength over time. However, it was not a significant harmful criterion. Therefore, the incorporation of recycled aggregates in cementitious materials is considered a technical and sustainable solution.


2020 ◽  
Vol 10 (13) ◽  
pp. 4441 ◽  
Author(s):  
Anna M. Grabiec ◽  
Daniel Zawal ◽  
Waheed Adewale Rasaq

The paper presents the influence of different curing conditions—wet, dry, and protection against water evaporation (PEV)—on selected properties of concretes with different amounts of recycled concrete aggregate (RCA) previously subjected to atmospheric CO2 sequestration. Two types of cement were used, Portland cement and blast-furnace slag cement. The study was performed in laboratory conditions (at the temperature of 20 ± 1 °C and relative humidity of about 60%), according to currently applicable test procedures for most of the measured characteristics of concrete. Additionally, the eco-efficiency indexes (bi and ci) as well as the eco-durability S-CO2 index were calculated. It was found that dry conditions cause the properties of concrete to deteriorate, especially concrete made of blast-furnace slag cement, while PEV allows the achievement of results comparable to wet conditions. Moreover, for series with the highest amounts of coarse recycled aggregate and after longer periods of curing, the difference between the effects of wet curing and protection against water evaporation disappears. The eco-efficiency and eco-durability indexes approach confirms the beneficial effect of blast-furnace slag cement used as a binder, but on the condition of using a proper way of curing.


2021 ◽  
Vol 11 (10) ◽  
pp. 4409
Author(s):  
Daniel Alberto Zuluaga-Astudillo ◽  
Hugo Alexander Rondón-Quintana ◽  
Carlos Alfonso Zafra-Mejía

Hot-mix asphalts exposed to hot weather and high traffic volumes can display rutting distress. A material that can be used to increase the stiffness of asphalt binders is gilsonite. On the other hand, from an environmental point of view, the virgin natural aggregates of asphalt mixtures can be replaced with recycled concrete aggregates. For these reasons, this study modified the asphalt binder with gilsonite by wet-process to improve rutting resistance, and replaced (by mass and volume) part of the coarse fraction of the aggregate with recycled concrete aggregate in two hot-mix asphalts with different gradations. Unlike other studies, a larger experimental phase was used here. Marshall, indirect tensile strength, resilient modulus, permanent deformation, fatigue resistance, and Cantabro tests were performed. An ANOVA test was carried out. If the replacement of the virgin aggregate by recycled concrete aggregates was made by volume, both materials (gilsonite and recycled concrete aggregate) could be used in hot-mix asphalts for thick-asphalt layers in high temperature climates and any level of traffic. The use of both materials in hot-mix asphalts is not recommended for thin-asphalt layers in low temperatures climates. It is not advisable to replace the aggregates by mass.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Hisham Qasrawi ◽  
Iqbal Marie

The effect of using recycled concrete aggregates (RCA) on the basic properties of normal concrete is studied. First, recycled aggregate properties have been determined and compared to those of normal aggregates. Except for absorption, there was not a significant difference between the two. Later, recycled aggregates were introduced in concrete mixes. In these mixes, natural coarse aggregate was partly or totally replaced by recycled aggregates. Results show that the use of recycled aggregates has an adverse effect on the workability and air content of fresh concrete. Depending on the water/cement ratio and on the percent of the normal aggregate replaced by RCA, the concrete strength is reduced by 5% to 25%, while the tensile strength is reduced by 4% to 14%. All results are compared with previous research. As new in this research, the paper introduces a simple formula for the prediction of the modulus of elasticity of RCA concrete. Furthermore, the paper shows the variation of the air content of RAC.


Author(s):  
Anna M. Grabiec ◽  
Daniel Zawal ◽  
Waheed Adewale Rasaq

The paper presents the influence of different curing conditions &ndash; wet, dry and protection against water evaporation on selected properties of concretes with different amount of recycled concrete aggregate previously subjected to atmospheric CO2 sequestration. Additionally, the eco-efficiency bi and ci indexes as well as eco-durability S-CO2 index were calculated. It was found that dry conditions deteriorate the properties of concrete, especially made of blast furnace slag cement, while protection against evaporation allows to achieve results comparable to wet conditions. Moreover, for series with the highest amount of coarse recycled aggregate and after longer period of curing, the difference between the effects of wet curing and protection against water evaporation disappears. The eco-efficiency and eco-durability indexes approach confirms the beneficial effect of blast-furnace slag cement used as a binder but on condition of proper way of curing.


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.


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