Resonance Fatigue Behaviour of Concretes with Recycled Cement and Aggregate

The huge increase in production of construction and demolition waste (CDW) worldwide is leading to the valorisation of as recycled aggregates. One of the most promising alternatives is its use as a recycled aggregate in the manufacture of structural concrete, which motivates the study of the dynamic behaviour of these materials in order to ensure their suitability for use in elements subjected to dynamic loads. This work evaluated the resonant compressive fatigue behaviour of structural concretes with 25% or 50% recycled mixed aggregates, either individually or in combination with 25% recycled cement of clay-based materials both from CDW. All mixes were subjected to compressive fatigue tests using the accelerated Locati method. Regarding the fatigue limit, the results showed that for all mixes, it was between 30% and 45% of the compressive strength. In addition, a correlation was also found between the resonance frequency of the test and the deformation suffered by the specimen. This correlation enabled the estimation of the fatigue limit through a more stable parameter than the strain measured by strain gauges, namely, the resonance frequency. In addition, it was found that the resonance frequency of the test changed as the specimen damage increased. This observation enabled the estimation of the fatigue limit through a more stable parameter than the strain measured by strain gauges, namely, the resonance frequency.

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Concrete Production of Hot Asphalt Using Recycled Aggregates CDW

Materials Science Forum ◽

10.4028/www.scientific.net/msf.881.346 ◽

2016 ◽

Vol 881 ◽

pp. 346-350 ◽

Cited By ~ 2

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

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Effects of Recycled Aggregate Resin (RAR) in Concrete Material

International Journal of Sustainable Construction Engineering Technology ◽

10.30880/ijscet.2020.11.02.006 ◽

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.

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Evaluation of the physical-mechanical properties of cement-lime based masonry mortars produced with mixed recycled aggregates

Materiales de Construcción ◽

10.3989/mc.2020.02819 ◽

2020 ◽

Vol 70 (337) ◽

pp. 210 ◽

Cited By ~ 2

Author(s):

R. L.S. Ferreira ◽

M. A.S. Anjos ◽

E. F. Ledesma ◽

J. E.S. Pereira ◽

A. K.C. Nóbrega

Keyword(s):

Mechanical Properties ◽

Construction And Demolition Waste ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Demolition Waste ◽

Long Run ◽

Lime Mortars ◽

Binder Ratio ◽

Mechanical Strengths ◽

One Way Anova

This study investigated the physical-mechanical effects of cement-lime mortars containing recycled aggregate of construction and demolition waste (CDW). The natural aggregate (NA) was replaced by volume at 25%, 50%, 75% and 100% by mixed recycled aggregate (MRA) obtained from the CDW crushing. Five types of mortars were prepared with a volumetric ratio of 1:1:6 (cement, lime and aggregate) and water/binder ratio based on the fixed consistency of 260 mm. The effects of MRA on fresh and hardened mortars’ properties were analyzed. The results were analyzed using a one-way ANOVA. MRA incorporation improved most of the physical-mechanical properties of mortars tested, except for hardened bulk density, water absorption and porosity. In the long-run, mechanical strengths significantly increased in all compositions, especially those with higher percentages of MRA. The results obtained showed that the use of MRA in masonry mortars is an alternative to reduce the generation of waste and consumption of natural resources.

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Life Cycle Economic and Environmental Impacts of CDW Recycled Aggregates in Roadway Construction and Rehabilitation

Sustainability ◽

10.3390/su13158611 ◽

2021 ◽

Vol 13 (15) ◽

pp. 8611

Author(s):

Yunpeng Zhao ◽

Dimitrios Goulias ◽

Luca Tefa ◽

Marco Bassani

Keyword(s):

Life Cycle ◽

Environmental Benefits ◽

Construction And Demolition Waste ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Base Layer ◽

Cement Kiln ◽

Demolition Waste ◽

Recycled Materials ◽

Roadway Construction

The use of recycled materials in roadway construction and rehabilitation can achieve significant benefits in saving natural resources, reducing energy, greenhouse gas emissions and costs. Construction and demolition waste (CDW) recycled aggregate as an alternative to natural one can enhance sustainability benefits in roadway infrastructure. The objective of this study was to quantitatively assess the life cycle economic and environmental benefits when alternative stabilized-CDW aggregates are used in pavement construction. Comparative analysis was conducted on a pavement project representative of typical construction practices in northern Italy so as to quantify such benefits. The proposed alternative sustainable construction strategies considered CDW aggregates stabilized with both cement and cement kiln dust (CKD) for the base layer of the roadway. The life cycle assessment results indicate that using CDW aggregate stabilized with CKD results in considerable cost savings and environmental benefits due to (i) lower energy consumption and emissions generation during material processing and (ii) reduction in landfill disposal. The benefits illustrated in this analysis should encourage the wider adoption of stabilized CDW aggregate in roadway construction and rehabilitation. In terms of transferability, the analysis approach suggested in this study can be used to assess the economic and environmental benefits of these and other recycled materials in roadway infrastructure elsewhere.

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Preliminary Analysis of the Use of Construction Waste to Replace Conventional Aggregates in Concrete

Buildings ◽

10.3390/buildings11030081 ◽

2021 ◽

Vol 11 (3) ◽

pp. 81

Author(s):

Fernando A. N. Silva ◽

João M. P. Q. Delgado ◽

António C. Azevedo ◽

António G. B. Lima ◽

Castorina S. Vieira

Keyword(s):

Compressive Strength ◽

Coarse Aggregate ◽

Recycled Aggregate Concrete ◽

Construction And Demolition Waste ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Fine Aggregate ◽

Demolition Waste ◽

Fine Aggregates ◽

Mechanical Strengths

This work aims to study the influence of using construction and demolition waste in the replacement of coarse and fine aggregate to produce recycled aggregate concrete (RAC). A moderate compressive strength concrete made with usual fine and coarse aggregate was used as a benchmark material. Compressive and split tensile tests were performed using 120 cylindrical concrete specimens with 150 mm diameter and 300 mm length. Four-point flexural tests in reinforced beams made with conventional concrete and RAC were performed. The results obtained showed that the use of recycled fine aggregates, in both percentages of substitution investigated—50% and 100%— did not generate any deleterious influence on the values of compressive strength and split tensile strength of the RACs produced. Tin fact, the mechanical strengths of RACs produced with recycled fine aggregate were equal or higher than those from the reference concrete. The same behavior was not observed, however, when the recycled coarse aggregate was used. For this case, decreases in concrete mechanical strengths were observed, especially in compressive strength, with values around 35% lower when compared to the reference concrete. Tensile mechanical tests results confirmed the excellent behavior of all RACs made with replacement of usual fine aggregates by recycled. Bending tests performed in reinforced RAC beams had as objective to evaluate the deformation profile of the beams. The obtained results showed that RAC beams with full replacement of usual fine aggregate by the recycled aggregates have presented little changes in the global behavior, an aspect that encourages its use.

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Development of Concrete Incorporating Recycled Aggregates, Hydrated Lime and Natural Volcanic Pozzolan

Infrastructures ◽

10.3390/infrastructures6110155 ◽

2021 ◽

Vol 6 (11) ◽

pp. 155

Author(s):

Natividad Garcia-Troncoso ◽

Bowen Xu ◽

Wilhenn Probst-Pesantez

Keyword(s):

Compressive Strength ◽

Recycled Concrete ◽

Construction And Demolition Waste ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Partial Replacement ◽

Demolition Waste ◽

Crushed Concrete ◽

Natural Pozzolana ◽

Concrete Materials

Recycling of construction and demolition waste is a central point of discussion throughout the world. The application of recycled concrete as partial replacement of mineral aggregates in concrete mixes is one of the alternatives in the reduction of pollution and savings in carbon emissions. The combined influence of the recycled crushed concrete, lime, and natural pozzolana on the mechanical and sustainable properties of concrete materials is firstly proposed in this study. In this research, unconventional construction materials are employed to produce concrete: the recycled crushed concrete is used as coarse aggregate, while lime and natural pozzolana are used as a partial replacement for cement. Substitutions of 10%, 20%, 50% of gravel are made with recycled aggregates, and 2%, 5%, 10% of cement with lime and natural pozzolan. Tests on the fresh and hardened properties, destructive (compressive strength) and non-destructive tests (sclerometer rebound and ultrasound) of mixtures are carried out. It is shown that the use of recycled materials can provide an increase in compressive strength of up to 34% with respect to conventional concrete. Life cycle cost and sustainability assessments indicate that concrete materials incorporating recycled aggregate possess good economic and environmental impacts.

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A Novel Conceptual Approach for Predicting the Mechanical Properties of Recycled Aggregate Concrete

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.847.156 ◽

2016 ◽

Vol 847 ◽

pp. 156-165

Author(s):

Marco Pepe ◽

Eduardus Koenders ◽

Romildo Dias Toledo Filho ◽

Enzo Martinelli

Keyword(s):

Mechanical Properties ◽

Recycled Concrete ◽

Recycled Aggregate Concrete ◽

Construction And Demolition Waste ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Conceptual Approach ◽

Demolition Waste ◽

Predictive Capacity ◽

Moisture Condition

The construction sector is more and more committed to reduce its environmental impacts. One of the key actions undertaken in the last decade deals with the ability of turning construction and demolition waste into new raw materials. For instance, the use of recycled aggregates for producing new concrete was one of the most investigated. Thus, in the last decade, plenty of researches were involved in project on characterising the mechanical behaviour of concrete made with recycled aggregates. However, these projects were mainly experimental in nature and generally led to merely empirical formulations. Conversely, this paper is intended at providing a contribution for predicting the mechanical properties of Recycled Aggregates Concrete (RAC). Particularly, it aims at quantifying the effect of replacing ordinary aggregates with Recycled Concrete Aggregates (RCA) on the resulting compressive strength of RAC. To this end, a conceptual model considering both the relevant physical properties of regular and recycled aggregates, including the attached mortar content, and the hydration reactions of Portland cement paste is proposed. The actual predictive capacity of the proposed model is assessed through an experimental validation against experimental tests carried out on several concrete batches produced with various values for the different keys parameters, such as the nominal water-to-cement ratio, the aggregates replacement ratio and the initial moisture condition of aggregates. Both the experimental data and the theoretical formulations proposed in this paper stem out from the inter-university collaboration developed as part of the EU funded EnCoRe Project (www.encore-fp7.unisa.it).

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Influence of Moisture States of Recycled Coarse Aggregates on the Slump Test

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.742.379 ◽

2013 ◽

Vol 742 ◽

pp. 379-383 ◽

Cited By ~ 5

Author(s):

Julia García González ◽

Desirée Rodríguez Robles ◽

Andrés Juan Valdés ◽

Julia M. Morán del Pozo ◽

M. Ignacio Guerra Romero

Keyword(s):

Free Water ◽

Construction And Demolition Waste ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Construction Sector ◽

Inexpensive Method ◽

Demolition Waste ◽

Coarse Aggregates ◽

Subsequent Elimination ◽

Natural Aggregates

The use of recycled aggregate to produce new concretes has become increasingly widespread, and numerous studies have demonstrated that the final product performs similarly to traditional concrete. However, construction and demolition waste (CDW) presents certain characteristics which could limit its acceptance in the construction sector due to worse performance than natural aggregates. One example of this is water absorption, which in recycled aggregates reaches such high values that the amount of free water calculated for mixing the concrete is affected, consequently impacting on the concrete's properties, especially consistency. This paper reports the possibility of solving this problem with a simple and inexpensive method; pre-saturation of recycled aggregates prior to adding them to the mix. The results of two different pre-treatments are compared; one consisted of immersing the aggregates in water for 10 minutes and the other, in addition to the above procedure, included a brief period of air drying and subsequent elimination of surface water from the aggregate. Both pre-treatments were found to solve the problem of consistency.

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Influence of Wetting and Drying Cycles on Physical and Mechanical Behavior of Recycled Aggregate Concrete

Materials ◽

10.3390/ma13245675 ◽

2020 ◽

Vol 13 (24) ◽

pp. 5675

Author(s):

Caroline S. Rangel ◽

Mayara Amario ◽

Marco Pepe ◽

Enzo Martinelli ◽

Romildo D. Toledo Filho

Keyword(s):

Recycled Concrete ◽

Recycled Aggregate Concrete ◽

Construction And Demolition Waste ◽

Recycled Aggregate ◽

Recycled Aggregates ◽

Demolition Waste ◽

Wetting And Drying ◽

Aggregate Concrete ◽

Wetting And Drying Cycles ◽

The Impact

Recently, concerns have been rising about the impact of increasing the depletion of natural resources and the relevant generation of construction and demolition waste, on the environment and economy. Therefore, several efforts have been made to promote sustainable efficiency in the construction industry and the use of recycled aggregates derived from concrete debris for new concrete mixtures (leading to so-called recycled aggregate concrete, RAC) is one of the most promising solutions. Unfortunately, there are still gaps in knowledge regarding the durability performances of RAC. In this study, we investigate durability of structural RAC subjected to wet-dry cycles. We analyze the results of an experimental campaign aimed at evaluating the degradation process induced by wetting and drying cycles on the key physical and mechanical properties of normal- and high-strength concrete, produced with coarse recycled concrete aggregates (RCAs) of different sizes and origins. On the basis of the results we propose a degradation law for wetting and drying cycles, which explicitly makes a possible correlation between the initial concrete porosity, directly related to the specific properties of the RCAs and the resulting level of damage obtained in RAC samples.

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The potency of recycled aggregate in new concrete: a review

Construction Innovation ◽

10.1108/ci-07-2018-0056 ◽

2019 ◽

Vol 19 (4) ◽

pp. 594-613 ◽

Cited By ~ 3

Author(s):

Emmanuel Ejiofor Anike ◽

Messaoud Saidani ◽

Eshmaiel Ganjian ◽

Mark Tyrer ◽

Adegoke Omotayo Olubanwo

Keyword(s):

Research Work ◽

Recycled Aggregate Concrete ◽

Construction And Demolition Waste ◽

Recycled Aggregate ◽

Mix Design ◽

Recycled Aggregates ◽

Demolition Waste ◽

Aggregate Concrete ◽

Content Type ◽

Natural Aggregate

Purpose This paper aims to review the effect of using recycled aggregates (RA) on the properties of recycled aggregate concrete (RAC) following the steady rise in global demand for concrete and the large generation of construction and demolition waste. Design/methodology/approach This study reviewed relevant literature of research work carried out by previous researchers, leading to a deeper understanding of the properties of both RA and RAC. The properties of RA and RAC reported in the various studies were then compared to their corresponding natural aggregate (NA) and natural aggregate concrete, as well as the specifications provided in different codes of practice. In addition, the mix design methods appropriate to RAC and the cost implication of using RA were reviewed. Findings Findings show that the contribution of RA to strength appears inferior in comparison to NA. The shortcoming is attributed to the mortar attached to the RA, which raises its water absorption capacity and lowers its density relative to those of NA. However, it has been reported that the use of regulated quantity of RA, new mixing and proportioning methods, the addition of admixtures and strengthening materials such as steel fibres, can improve both mechanical and durability properties of RAC. Cost evaluation also showed that some savings can be realized by using RA instead of NA. Originality/value This research serves as a guide for future works and suggests that the use of RA as aggregate in new concrete is technically possible, depending on the mix design method adopted.

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