scholarly journals Innovative Technologies and Logistical Solutions for the Reuse of Demolished Concrete in the Construction of Cement Concrete Pavements

2013 ◽  
Vol 8-9 ◽  
pp. 259-268
Author(s):  
Marius Teodor Muscalu ◽  
Andrei Radu ◽  
Nicolae Taranu ◽  
Mihai Budescu ◽  
Irina Lungu
Keyword(s):  
Recycled Aggregates ◽  
Concrete Pavements ◽  
Original Performance ◽  
Cement Concrete ◽  
Roller Compacted Concrete ◽  
Rigid Pavements ◽  
Concrete Mixtures ◽  
Negative Effect ◽  
Natural Aggregates ◽  
Technical Solutions

The paper presents the results and conclusions of investigations aiming to encourage the use of recycled materials, namely recycled aggregates (RA) and recycled steel fibers (RSF), in the construction of durable, economic and environmental friendly rigid pavements. To minimize and limit the negative effect of RA on the mechanical properties of cement concrete pavements, the research program considered both, development of technical solutions to improve the performance characteristics of RA particle, and RSF disperse reinforcement of concrete mixtures. Roller compacted concrete (RCC) cylindrical and prismatic test specimens manufactured with natural aggregates (NA) and original/performance improved RA have been subjected to flexure and compressive testes to evaluate the influence and contribution of developed technologies. Finally, guidelines and considerations for the use of RA in RCC and plain cement concrete (PCC) pavements are drawn.

Use of Recycled Materials in the Construction of Roller Compacted Concrete (RCC) Pavements

2013 ◽  
Vol 649 ◽  
pp. 262-265 ◽  
Author(s):  
Marius Teodor Muscalu ◽  
Andrei Radu ◽  
Mihai Budescu ◽  
Nicolae Ţăranu ◽  
Eugen Florescu
Keyword(s):  
Research Program ◽  
Construction Materials ◽  
Recycled Aggregates ◽  
Concrete Pavements ◽  
Cement Concrete ◽  
Roller Compacted Concrete ◽  
Reinforced Cement ◽  
Mechanical Performances ◽  
Recycled Steel ◽  
Technical Recommendations

This paper presents the results of laboratory studies, undertaken by the authors, in the frame of 4D-POSTDOC research program :"Innovative technologies and logistical solutions for the reuse of demolition and construction waste in the construction of cement concrete and fiber reinforced cement concrete pavements". After the presentation of the main objectives of this research program, and of the specific characteristics of the demolition wastes investigated in parallel with those of conventional construction materials, the possibility of using these materials for the preparation of the roller compacted concrete (RCC) is investigated. Finally, conclusions on the influence of recycled aggregates and recycled steel fibers on the mechanical performances of RCC and technical recommendations for the use of this more efficient material and of the involved technology for the construction of sustainable road infrastructures are formulated.

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 The Effect of Fine and Coarse Recycled Aggregates on Fresh and Mechanical Properties of Self-Compacting Concrete

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1120 ◽  
Author(s):  
Mahmoud Nili ◽  
Hossein Sasanipour ◽  
Farhad Aslani
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Energy Absorption ◽  
Silica Fume ◽  
The Self ◽  
Recycled Aggregates ◽  
Self Compacting Concrete ◽  
Concrete Mixtures ◽  
Natural Aggregates ◽  
Recycled Material

Today, the use of recycled aggregates as a substitute for a part of the natural aggregates in concrete production is increasing. This approach is essential because the resources for natural aggregates are decreasing in the world. In the present study, the effects of recycled concrete aggregates as a partial replacement for fine (by 50%) and coarse aggregates (by 100%) were examined in the self-compacting concrete mixtures which contain air-entraining agents and silica fumes. Two series of self-compacting concrete mixes have been prepared. In the first series, fine and coarse recycled mixtures respectively with 50% and 100% replacement with air entraining agent were used. In the second series, fine recycled (with 50% replacement) and coarse recycled (with 100% replacement) were used with silica fume. The rheological properties of the self-compacting concrete (SCC) were determined using slump-flow and J-ring tests. The tests of compressive strength, tensile strength, and compressive stress-strain behavior were performed on both series. The results indicated that air-entraining agent and silica fume have an important role in stabilization of fresh properties of the mixtures. The results of tests indicated a decrease in compressive strength, modulus of elasticity, and energy absorption of concrete mixtures containing air entrained agent. Also, the results showed that complete replacement (100%) with coarse recycled material had no significant effect on mechanical strength, while replacement with 50% fine recycled material has reduced compressive strength, tensile strength, and energy absorption.

scholarly journals VERIFICATION OF THE BASIC PROPERTIES OF RECYCLED AND NATURAL AGGREGATES

2019 ◽  
Vol 22 ◽  
pp. 67-71
Author(s):  
Karel Mikulica ◽  
Iveta Hájková
Keyword(s):  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregates ◽  
Concrete Aggregate ◽  
Building Structures ◽  
Recycled Concrete Aggregate ◽  
Apartment Building ◽  
Demolition Waste ◽  
Concrete Mixtures ◽  
Natural Aggregates

In the future, it is planned to use up to 50% of construction and demolition waste (C&DW) for the production of new building structures. This leads us to think about how we can use recycled concrete aggregate (RCA) as a substitute for natural aggregate (NA) in concrete mixtures. This is why we compare the two typical representatives of recycled aggregates with a representative of natural aggregates. As a representative of recycled aggregates, we chose pure concrete recycled from the cutting of concrete and mixed recyclate from the demolition of the apartment building. As a representative of natural stone, we chose the extracted aggregate.

scholarly journals Resistance of Recycled Aggregate Concrete (RAC) Subjected to Drying-Wetting Cycles to Attack of Magnesium and Sodium Sulfates

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Esam Hewayde ◽  
Alireza Pachenari ◽  
Hussin Al-Eleaj
Keyword(s):  
Compressive Strength ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Partial Immersion ◽  
Concrete Mixtures ◽  
Sulfate Solutions ◽  
Mass Losses ◽  
Natural Aggregates ◽  
Sodium Sulfates

Recycled aggregates were widely used in the concrete industry as a replacement of natural aggregates in the last two decades. In this study, the resistance of concrete mixtures having various levels of recycled aggregate as a replacement of natural coarse aggregate to the attack of magnesium and sodium sulfates was investigated. Five mixtures made with 0%, 25%, 50%, 75%, and 100% recycled aggregate were partially immersed in magnesium and sodium sulfate solutions having concentrations of 2.5%, 4.5%, and 6.5% and subjected to drying-wetting cycles for a total of 10 weeks. Mass losses of concrete specimens owing to the attack of sulfate solutions and the effect of drying-wetting cycles were recorded weekly. Results show that the incorporation of recycled aggregate decreased the compressive strength of concrete at ages of 7 and 28 days. The decline in the compressive strength was more significant when the replacement percentage exceeds 50%. Mass losses of concrete specimens were found to be increased as the level of recycled aggregate increased. Mass losses of concrete specimens having 100% recycled aggregate were approximately as twice as those of concrete specimens having 0% recycled aggregate owing to 10 weeks of partial immersion in magnesium sulfate solutions of concentrations of 2.5%, 4.5%, and 6.5%. The attack of sodium sulfates was less aggressive than that of the magnesium sulfates. Results also show that the reduction in the compressive strength is directly proportional to the mass loss following a linear equation of R-squared value of 0.937.

scholarly journals Mechanical Performance of Bio-Based FRP-Confined Recycled Aggregate Concrete under Uniaxial Compression

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1778
Author(s):  
Elhem Ghorbel ◽  
Mariem Limaiem ◽  
George Wardeh
Keyword(s):  
Mechanical Performance ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Fiber Reinforced ◽  
Traditional System ◽  
Concrete Mixtures ◽  
Compressive Performance ◽  
Natural Aggregates ◽  
Frp Confinement

This research investigates the effectiveness of bio-sourced flax fiber-reinforced polymer in comparison with a traditional system based on carbon fiber-reinforced epoxy polymer in order to confine recycled aggregate concretes. The experimental investigation was conducted on two series of concrete including three mixtures with 30%, 50%, and 100% of recycled aggregates and a reference concrete made with natural aggregates. The concrete mixtures were intended for a frost environment where an air-entraining agent was added to the mixture of the second series to achieve 4% air content. The first part of the present work is experimental and aimed to characterize the compressive performance of confined materials. The results indicated that bio-sourced composites are efficient in strengthening recycled aggregates concrete, especially the air-entrained one. It was also found that the compressive strength and the strain enhancement obtained from FRP confinement are little affected by the replacement ratio. The second part was dedicated to the analytical modeling of mechanical properties and stress–strain curves under compression. With the most adequate ultimate strength and strain prediction relationships, the full behavior of FRP-confined concrete can be predicted using the model developed by Ghorbel et al. to account for the presence of recycled aggregates in concrete mixtures.

scholarly journals Behavior of Various Concrete Mixes with Inclusion of Recycled Coarse Aggregates Based on Durability Point of View

2020 ◽  
Vol 9 (3) ◽  
pp. 817-823
Keyword(s):  
Construction Material ◽  
Concrete Structures ◽  
Recycled Aggregates ◽  
Effect Of Temperature ◽  
Partial Replacement ◽  
Cement Concrete ◽  
Thermal Cycles ◽  
Temperature Variations ◽  
Chemical Attack ◽  
Natural Aggregates

Cement concrete is the most extensively used construction material in the world with about six billion tons produced every year. It has emerged as the dominant construction material for the infrastructure needs of the 21st century. Aggregate is one of the main ingredients in producing concrete i.e. 75% of the concrete mass. The strength of the concrete produced is dependent on the properties of aggregates used, hence there is huge demand for this material. In order to reduce the use of natural aggregates from natural resources, the use of recycled aggregates in concretes is an interesting solution. It helps in reducing the cost of concrete manufacturing and also has numerous indirect benefits such as reduction in land-fill cost, energy saving, and protecting the environment from possible pollution effects. Durability and strength are two most important criteria for any concrete structures. One of the main causes of deterioration in concrete structures is its exposure to temperature variations mainly due to solar radiation and harmful chemicals that may be found in nature such as in industrial effluents. The most aggressive chemicals that affect the long term durability of concrete structures are the magnesium, sulphates and chlorides. These chemicals in presence of water increases the porosity of concrete and leads to loss of weight and strength. Hence this paper investigates the effect of thermal cycles and chemical attack on M20 & M25 grade cement concrete in partial replacement of natural aggregates with recycled aggregates with proportion of 10%, 20% and 30%. The effect of temperature variations were studied by analyzing loss in compressive strength after applying various thermal cycles on concrete cubes at 60o C and 90 o C. The chemical resistance of the concretes was studied through chemical attack by immersing concrete cubes in 5% MgSO4 , H2SO4 and HCl solution and loss in strength and weight were measured at 7, 28, 60 and 90 days. The result shows possible use of RCA as 20% for both M20 & M25 grade concrete, and resistance to thermal cycles and chemical attack shows reduction in strength and weight with time

TECHNICAL SOLUTIONS TO IMPROVE PERFORMANCE OF THE RECYCLED CEMENT CONCRETE AGGREGATES FOR DURABLE ROAD PAVEMENTS

2013 ◽  
Vol 12 (3) ◽  
pp. 595-602 ◽  
Author(s):  
Nicolae Taranu ◽  
Marius Muscalu ◽  
Radu Andrei ◽  
Irina Lungu ◽  
Mihai Budescu ◽  
...  
Keyword(s):  
Cement Concrete ◽  
Improve Performance ◽  
Concrete Aggregates ◽  
Technical Solutions

scholarly journals Mortars with Recycled Aggregates from Building-Related Processes: A ‘Four-Step’ Methodological Proposal for a Review

2021 ◽  
Vol 13 (5) ◽  
pp. 2756
Author(s):  
Federica Vitale ◽  
Maurizio Nicolella
Keyword(s):  
Building Materials ◽  
Thermal Analyses ◽  
Construction Materials ◽  
Physical And Mechanical Properties ◽  
Research Trends ◽  
Mix Design ◽  
Recycled Aggregates ◽  
Design Parameters ◽  
Natural Aggregates ◽  
By Products

Because the production of aggregates for mortar and concrete is no longer sustainable, many attempts have been made to replace natural aggregates (NA) with recycled aggregates (RA) sourced from factories, recycling centers, and human activities such as construction and demolition works (C&D). This article reviews papers concerning mortars with fine RA from C&D debris, and from the by-products of the manufacturing and recycling processes of building materials. A four-step methodology based on searching, screening, clustering, and summarizing was proposed. The clustering variables were the type of aggregate, mix design parameters, tested properties, patents, and availability on the market. The number and the type of the clustering variables of each paper were analysed and compared. The results showed that the mortars were mainly characterized through their physical and mechanical properties, whereas few durability and thermal analyses were carried out. Moreover, few fine RA were sourced from the production waste of construction materials. Finally, there were no patents or products available on the market. The outcomes presented in this paper underlined the research trends that are useful to improve the knowledge on the suitability of fine RA from building-related processes in mortars.

Sign in / Sign up

Export Citation Format

Share Document