scholarly journals Concretes with binary mixtures of artificial pozzolans and concrete demolition waste

2020 ◽  
Vol 20 (4) ◽  
pp. 177-188
Author(s):  
Cristian Jonathan Franco de Lima ◽  
Francisco Roger Carneiro Ribeiro ◽  
Geraldo Cechella Isaia ◽  
Mauricio Mancio
Keyword(s):  
Binary Mixtures ◽  
Modulus Of Elasticity ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Demolition Waste ◽  
Durability Test ◽  
Concrete Mixtures ◽  
Pozzolanic Materials

Abstract The objective of this study is to analyse the use of binary mixtures of pozzolanic materials and concrete demolition waste in concrete mixtures, especially the resulting mechanical properties and durability. A total of ten concrete formulations were produced distinguishing them in different types using different Portland cements, different artificial pozzolans and coarse aggregates from concrete demolition. The particular properties of each formulation were verified by testing the axial compressive strength, longitudinal modulus of elasticity and penetration of chloride under immersion. Substitutions were of 15% w.t. and 30% w.t. natural coarse aggregate substituted with concrete demolition waste and, in the case of binary mixtures, additional 25% w.t. of the binder agglomerate substituted with rice husk ash or fly ash. Results showed that the final strength to axial compression and modulus of elasticity of concrete mixtures were negatively affected by utilising demolition waste, but this effect was balanced by adding supplementary cementitious materials. Regarding the durability test, it was found that the lowest coefficients occurred in the mixtures using CP V-ARI, together with artificial pozzolans, in mixtures with 15% w.t. substitution of natural aggregate with recycled aggregate. It was concluded that using recycled aggregates in concrete is viable but conditioned to the concomitant use of pozzolanic materials.

scholarly journals Long-term performance of sustainable pavements using ternary blended concrete with recycled aggregates

2021 ◽  
Author(s):  
Gilson Lomboy ◽  
Douglas Cleary ◽  
Seth Wagner ◽  
Yusef Mehta ◽  
Danielle Kennedy ◽  
...  
Keyword(s):  
Portland Cement ◽  
Cementitious Materials ◽  
Recycled Concrete ◽  
Supplementary Cementitious Materials ◽  
Recycled Aggregates ◽  
Concrete Aggregate ◽  
Portland Cement Concrete ◽  
Cement Concrete ◽  
Concrete Aggregates ◽  
Concrete Mixtures

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.

scholarly journals Development and Guidance of Green Concrete for Leed™ Applications

2010 ◽  
Vol 5 (4) ◽  
pp. 111-120
Author(s):  
John T Kevern
Keyword(s):  
Green Building ◽  
Cementitious Materials ◽  
Recycled Concrete ◽  
Supplementary Cementitious Materials ◽  
Recycled Aggregate ◽  
Strength Development ◽  
Concrete Aggregate ◽  
Total Contribution ◽  
Recycled Materials ◽  
Concrete Mixtures

As green building rating systems such as LEED™ become more popular, the use of recycled materials in construction is increasing. Concrete can be produced with significant quantities of supplementary cementitious materials or recycled aggregate materials. However, modifying concrete mixture proportions for improved recycled content credits also impacts strength and long-term durability. Without properly understanding the effects recycled materials have on concrete, greener concrete can be less desirable from a lifecycle perspective from poor durability. This research investigates the impacts different types and quantities of supplementary cementitious materials and recycled concrete aggregate have on strength development and concrete durability, specifically deicer scaling. Improvements to deicer scaling resistance were investigated using a novel soybean oil sealer. The concrete mixtures were also evaluated within the LEED™ recycled materials criteria for selection based on economy and total contribution value. Considerations are included to assist designers in the selection of greener concrete mixtures for appropriate applications.

Fresh and Mechanical Properties of Sustainable Concrete Using Recycled Aggregates

2019 ◽  
Vol 803 ◽  
pp. 239-245
Author(s):  
Ahmad Khartabil ◽  
Samer Al Martini
Keyword(s):  
Construction Industry ◽  
United Arab Emirates ◽  
Construction Projects ◽  
Rapid Development ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Abu Dhabi ◽  
Natural Aggregates

In the last few decades, the United Arab Emirates (UAE) witnessed rapid development in the construction industry. It was recently emphasized to adopt sustainability practice in all aspects related to construction. The recent sustainable practice that was enforced by Dubai Municipality in construction field is “greening the concrete” by solely replacing the Portland Cement with supplementary cementitious materials (SCMs), such as grand granulated blast furnace slag (GGBS) and fly ash. On the other hand, the use of recycled aggregates can also contribute to the greening of concrete and to the reduction of carbon foot print from the construction industry in the UAE. Consequently, it is significant to study the suitability of local available recycled aggregate and their effect on concrete fresh and hardened properties, in order to expand the current practice. The recycled aggregates, used in this investigation, are obtained from a local recycled aggregates plant in Abu Dhabi using concrete from demolished buildings in Abu Dhabi. The natural aggregates in concrete mixtures were replaced by recycled aggregates with the following percentages: 20%, 40%, 60% and 100%. The concrete parameters investigated are mainly the slump retention, rheology and compressive strength. The results are analyzed to arrive to pertinent conclusions for the utilization of concrete with recycled aggregates in different types of construction projects.

scholarly journals Concrete produced with recycled aggregate: a durability analysis for structural use

2020 ◽  
Vol 13 (6) ◽  
Author(s):  
Lia Lorena Pimentel ◽  
Giovanna Falzetta Rizzo ◽  
Ana Elisabete Paganelli Guimarães de Avila Jacintho ◽  
Patrícia Stella Pucharelli Fontanini
Keyword(s):  
Cementitious Materials ◽  
Indirect Measurement ◽  
Absorption Capacity ◽  
Chloride Ions ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Structural Function ◽  
Demolition Waste ◽  
Durability Analysis

abstract: Construction and Demolition waste (CDW) is already used in many European countries as recycled aggregates to produce concrete for structural purposes. In Brazil, its use is still restricted to concretes with no structural function. The consumption of aggregates for the production of concrete is very large, and enabling the use of recycled aggregates in the production of concrete is essential to transform the civil construction industry into a more sustainable one. This work aimed to study the parameters that affect the durability of C30 grade concrete, produced with different types of recycled aggregate. We defined four types of coarse aggregates for carrying out this work: the natural (AN), the concrete (ARCO), the cementitious materials (ARCI) and the treated cementitious materials (ARCI Treated). We adopted 30% substitution content of natural aggregate for recycled aggregates. The treatment of the ARCI aggregate consisted of the application of water and cement solution, aiming to reduce its water absorption capacity. We determine the physical and mechanical characteristics of the concrete, in addition to carrying out indirect measurement tests of durability, by determining the permeability to air, penetration and migration of chloride ions, and determination of the carbonation depth. The results indicate that the concrete using the ARCO type aggregate, produced with 100% crushed concrete, presented characteristics like the reference concrete, indicating the possibility that it can be applied to reinforced concrete structures. As for the ARCI type aggregate, it presented inferior results when compared to the concrete reference for the tests of indirect measurement of durability, however, the concrete displayed good mechanical properties. The concrete produced with the treated ARCI did not perform better than the concrete with ARCI for most of the evaluated characteristics, indicating that the proposed treatment was not adequate.

Carbonation Resistance of Sustainable Concrete Using Recycled Aggregate and Supplementary Cementitious Materials

2019 ◽  
Vol 803 ◽  
pp. 246-252 ◽  
Author(s):  
Ahmad Khartabil ◽  
Samer Al Martini
Keyword(s):  
Portland Cement ◽  
Construction Industry ◽  
Cementitious Materials ◽  
Chloride Penetration ◽  
Supplementary Cementitious Materials ◽  
Recycled Aggregate ◽  
Concrete Mixture ◽  
Sustainable Concrete ◽  
Concrete Mixtures ◽  
Carbonation Resistance

Green concrete is a recent sustainable practice in UAE that was enforced by Dubai Municipality in construction field within the emirate of Dubai to reduce the carbon foot print in construction industry and to increase the durability of the structures. This led the construction industry to reduce the usage of ordinary portland cement by replacing it with supplementary cementitious materials (SCMs) such as Grand Granulated Blast Furnace Slag (GGBS) and flyash (FA). Incorporating GGBS or FA in concrete mixtures can improve durability parameters of hardened concrete, such as resistance to water permeability, reduced water absorption and chloride penetration. This ultimately increases the structure’s service life by increasing the threshold of concrete mixture for chloride induced corrosion. On the other hand, carbonation induced corrosion to concrete is usually being ignored or forgotten generally, due its usual slow rate ingression in plain portland cement concrete mixtures. Several studies showed that incorporating some types of SCM – especially at high percentage - can reduce the concrete resistance to carbonation. Additionally and for concrete with recycled aggregate, carbonation investigation should be taken into consideration. This is since recycled aggregates are reused aggregates that are extracted from demolished structures and buildings which were already subjected to different environmental exposures and deteriorations. Unlike chloride penetration, there is no direct ASTM standard test to anticipate the concrete mixture resistance to carbonation at early ages. In this study, concrete mixtures with flyash and different recycled aggregate replacement percentages are investigated for carbonation resistance in accelerated proposed method, considering concrete mixtures’ key parameters like water-cement ratio, and total cement content. The results are analyzed to arrive to pertinent conclusions for the best utilization of sustainable concrete for carbonation resistance.

Concrete Production of Hot Asphalt Using Recycled Aggregates CDW

2016 ◽  
Vol 881 ◽  
pp. 346-350 ◽  
Author(s):  
Luzana Leite Brasileiro ◽  
Fátima Maria de Souza Pereira ◽  
Pablo de Abreu Vieira ◽  
José Milton Elias de Matos
Keyword(s):  
Solid Waste ◽  
National Policy ◽  
Mechanical Tests ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Demolition Waste ◽  
Final Destination ◽  
Natural Aggregate ◽  
Concrete Production

Every year, there is a considerable increase in the exploitation of deposits to supply the market for aggregates. On the other hand, so does the production of solid waste from construction and demolition waste (CDW). In 2010 Brazil approved the PNRS (National Policy on Solid Waste), which sets out how the country should have their waste, encouraging recycling and sustainability. As an alternative to the above problem, this paper aims to investigate the feasibility of partial and total replacement of the asphalt concrete aggregates by recycled aggregates from CDW in order to reduce the environmental impacts caused by the operation of quarries and give an adequate final destination the residue produced by man in construction. Were carried out five (05) projects mixture of: the first (parameter of our research) used only natural aggregates (0% CDW) in the second, third and fourth replaced 25%, 50% and 75% respectively of natural aggregate by the recycled aggregate and the fifth and last, used only recycled aggregates (100% CDW). They carried out the characterization of the aggregates by means of physico-chemical and mechanical, analyzing them with reference based on specific standards paving. For mixtures, they calculated the volumetric parameters and performed mechanical tests of tensile strength and stability. The results indicate that the recycled aggregate, in a defined proportion, can replace the natural aggregate in the flexible pavements

scholarly journals Effects of Recycled Aggregate Resin (RAR) in Concrete Material

2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Sharifah Salwa Mohd Zuki ◽  
◽  
Shahiron Shahidan ◽  
Shivaraj Subramaniam ◽  
◽  
...  
Keyword(s):  
Epoxy Resin ◽  
Recycled Aggregate Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Engineering Properties ◽  
Recycled Aggregates ◽  
Hardened Concrete ◽  
Demolition Waste ◽  
Split Tensile Strength ◽  
Close Proximity

This paper discussed the recycled aggregates produced from construction and demolition waste and their utilization in concrete construction. Along with a brief overview of the engineering properties of recycled aggregates, the paper also summarizes the effect and use of recycled aggregates on the properties of fresh and hardened concrete. The recycled aggregates were treated with epoxy resin to reduce the water absorptions with different percentages of resin such as 0%, 25%, 50%, 75%, and 100%. Epoxy resin is widely used in recent years owing to the enhancing of mechanical and durability of the concrete. This research also showed, recycled aggregate concrete are close proximity to normal concrete in terms of split tensile strength, compression strength and wet density. The low usage of resin was obtained good strength concrete compared to high percentage contained treated aggregates due to low bonding between material.

scholarly journals Effect of Recycled Coarse Aggregates in Properties of Concrete

2008 ◽  
Vol 3 (4) ◽  
pp. 130-137 ◽  
Author(s):  
R Kumutha ◽  
K Vijai
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Modulus Of Elasticity ◽  
Coarse Aggregate ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Split Tensile Strength ◽  
Coarse Aggregates ◽  
The Cost

The properties of concrete containing coarse recycled aggregates were investigated. Laboratory trials were conducted to investigate the possibility of using recycled aggregates from the demolition wastes available locally as the replacement of natural coarse aggregates in concrete. A series of tests were carried out to determine the density, compressive strength, split tensile strength, flexural strength and modulus of elasticity of concrete with and without recycled aggregates. The water cement ratio was kept constant for all the mixes. The coarse aggregate in concrete was replaced with 0%, 20%, 40%, 60%, 80% and 100% recycled coarse aggregates. The test results indicated that the replacement of natural coarse aggregates by recycled aggregates up to 40% had little effect on the compressive strength, but higher levels of replacement reduced the compressive strength. A replacement level of 100% causes a reduction of 28% in compressive strength, 36% in split tensile strength and 50% in flexural strength. For strength characteristics, the results showed a gradual decrease in compressive strength, split tensile strength, flexural strength and modulus of elasticity as the percentage of recycled aggregate used in the specimens increased. 100% replacement of natural coarse aggregate by recycled aggregate resulted in 43% savings in the cost of coarse aggregates and 9% savings in the cost of concrete.

scholarly journals Failure risk of recycled aggregates concrete

2019 ◽  
Vol 281 ◽  
pp. 01017
Author(s):  
Frédéric Grondin ◽  
Menghuan Guo ◽  
Emmanuel Rozière ◽  
Ahmed Loukili
Keyword(s):  
Correlation Method ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Demolition Waste ◽  
Structural Class ◽  
The Sustainable Development ◽  
Failure Risk ◽  
Development Context ◽  
Cracking Process

In the sustainable development context, the use of demolition waste increases in the building industry. Recycled aggregates from the demolition of concrete structures are then mixed in new concrete. Furthermore, the performance evaluation of a these recycled aggregate concrete (RAC) mix is not only limited to the determination of its conventional mechanical properties. The failure risk of concrete elements in structures made from RAC needs a comprehensive analysis. For that, a study on the fracture process of RAC has been performed and compared with that of normal concrete of the same structural class. Acoustic emission technique and digital correlation method have been used to follow the cracking process. Also, a new modelling approach for the fracture behaviour of RAC at the mesoscopic scale has been developed. It has taken into account the old attached mortar surrounding recycled aggregates. Results show that RAC has a more brittle behaviour than ordinary concrete and the numerical analysis shows that cracks growth through the recycled aggregates which have brittleness behaviour.

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