scholarly journals Strength and Durability Studies on Geopolymer Recycled Aggregate Concrete

2018 ◽  
Vol 7 (2.24) ◽  
pp. 370 ◽  
Author(s):  
P Saravanakumar
Keyword(s):  
Construction Industry ◽  
Coarse Aggregate ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Geopolymer Concrete ◽  
Aggregate Concrete ◽  
Natural Aggregates ◽  
Strength And Durability ◽  
Durability Performance

This paper aims to study the engineering and durability properties of fly ash-based geopolymer recycled aggregate concrete and the results were presented in this paper. The addition of recycled coarse aggregate (RCA) retrieved from construction and demolition(C&D) wastes showed promising function in construction industry as an alternative to natural aggregates. It conserves enormous quantities of natural resources and reduces the space required for the landfill disposal of C&D wastes. In this study an increment of 25% partial replacements by weight of natural aggregates with recycled aggregates in geopolymer concrete up to 100% replacements were studied. The concrete containing virgin aggregate and ordinary Portland cement was consider as control concrete and the results of geopolymer recycled aggregate concrete (GP-RAC)  were compared with this. The fresh and mechanical properties of all the above four concrete mixes has been investigated. Results indicated that workability of geopolymer concrete decreases than control concrete and it took more than 24 hours to set. Geo polymer based recycled aggregate concrete exhibits better strength and durability performance than ordinary recycled aggregate concrete.  

Study on Performance of Recycled Aggregate Concrete

2011 ◽  
Vol 477 ◽  
pp. 280-289 ◽  
Author(s):  
Shao Wei Yao ◽  
Zhen Guo Gao ◽  
Chang Rui Wang
Keyword(s):  
Mechanical Properties ◽  
Coarse Aggregate ◽  
Physical And Mechanical Properties ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Chemical Solution ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Natural Aggregate ◽  
Strength And Durability

The properties of recycled coarse aggregate and the slump, the physical and mechanical properties and durability of recycled aggregate concrete were studied through tests. The results indicate that the slump, compressive strength and durability of concrete with recycled aggregate are lower than that of concrete with natural aggregate when recycled coarse aggregate fully absorbs water. However, the slump can be similar to that of concrete with natural aggregate. The properties of recycled aggregate concrete can be improved by strengthening the recycled coarse aggregate, and it is also found that the recycled coarse aggregate strengthened by grinding is superior to that soaked by chemical solution.

scholarly journals A Review on Alkali-Silica Reaction Evolution in Recycled Aggregate Concrete

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2625 ◽  
Author(s):  
Miguel Barreto Santos ◽  
Jorge De Brito ◽  
António Santos Silva
Keyword(s):  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Mitigation Measures ◽  
Alkali Silica Reaction ◽  
Aggregate Concrete ◽  
Reactive Silica ◽  
Natural Aggregates ◽  
Exposure Conditions ◽  
Lack Of Knowledge

Alkali-silica reaction (ASR) is one of the major degradation causes of concrete. This highly deleterious reaction has aroused the attention of researchers, in order to develop methodologies for its prevention and mitigation, but despite the efforts made, there is still no efficient cure to control its expansive consequences. The incorporation of recycled aggregates in concrete raises several ASR issues, mainly due to the difficult control of the source concrete reactivity level and the lack of knowledge on ASR’s evolution in new recycled aggregate concrete. This paper reviews several research works on ASR in concrete with recycled aggregates, and the main findings are presented in order to contribute to the knowledge and discussion of ASR in recycled aggregate concrete. It has been observed that age, exposure conditions, crushing and the heterogeneity source can influence the alkalis and reactive silica contents in the recycled aggregates. The use of low contents of highly reactive recycled aggregates as a replacement for natural aggregates can be done without an increase in expansion of concrete. ASR expansion tests and ASR mitigation measures need to be further researched to incorporate a higher content of recycled aggregates.

scholarly journals Effect of Recycled Aggregates on the Energy Dissipation Capacity of RC Beam subjected to Reverse Cyclic Flexural Loading

2021 ◽  
Vol 40 (1) ◽  
pp. 140-151
Author(s):  
Muhammad Rizwan Riaz ◽  
Rashid Hameed ◽  
Usman Akmal ◽  
Asad Ali Gillani ◽  
Muhammad Ilyas
Keyword(s):  
Energy Dissipation ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Rc Beam ◽  
Rc Beams ◽  
Aggregate Concrete ◽  
Flexural Loading ◽  
Energy Dissipation Capacity ◽  
Natural Aggregates

The energy dissipation capacity of concrete is an important aspect for a Reinforced Concrete (RC) structure to be seismically resistant. Various types of concrete incorporating sustainable materials are being developed these days such as recycled aggregate concrete. Determination of energy dissipation capacity of such new types of concrete is of great importance for their application in RC structures which are to be constructed in seismically active areas. In this regard, the experimental study presented in this contribution investigated the energy dissipation capacity of RC beams constructed using recycled aggregate concrete and subjected to three different deflection amplitude levels of reverse cyclic flexural loading. For this purpose, a total of 20 RC beams of cross section 75 x 150 mm and length of 1350 mm were cast using five different concrete compositions and tested. Among five different concrete compositions, one was control concrete containing 100% natural aggregates while the remaining four compositions were of recycled aggregate concrete containing natural and recycled aggregates. Four replacement levels (25%, 50%, 75%, and 100%) of natural aggregates with recycled aggregates were examined. Results indicated that the amplitude level of imposed deflection is an important factor which influenced the value of energy dissipated by RC beams. Further, results showed that RC beam constructed using recycled aggregate concrete containing 25% recycled aggregates exhibited energy dissipation capacity similar to or even better than that of control RC beam containing 100% natural aggregates.

scholarly journals Performance of Recycled Aggregate Concrete for M25 Grade Concrete

2019 ◽  
Vol 9 (2) ◽  
pp. 4694-4700
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Aggregate Concrete ◽  
Inorganic Particles ◽  
Natural Aggregates

Recycled aggregates (RCA) are the aggregates which are made up of crushed, inorganic particles that are obtained from the construction demolition debris. Now a day’s protection of environment is the ultimate challenge to the society. So the usage of RCA’s is the best alternative for the aggregates which are obtained naturally in the construction activity. The scope of using these recycled concrete aggregates is increasing day by day. It reduces the cost effectively as we are using waste concrete as recycled aggregates. The main focus of this paper is to use find the strength qualities of recycled aggregates so as to use it as an alternative for the natural aggregates in high strength concrete for various construction activities. Comparison of workability, compressive strength, tensile strength, elastic modulus and flexural strength of recycled aggregate concrete is made with natural aggregate concrete. Here M25 grade concrete is taken and the natural aggregates were replaced with recycled aggregates in various percentages of 0%, 25%, 50%, 75% and 100%. The mix design for these replacement ratios are done by using code of IS 10262-2009. In order to determine the properties which were mentioned above a total of 60 cubes, 10 beams and 40 cylinders were casted. The compressive strength and tensile strength of RCA concrete have been determined for 7 days and 28 days where as the modulus of elasticity and the flexural strength of RCA concrete are determined after curing for the period of 28 days. The tests done on RCA concrete are compared with concrete which is obtained by natural aggregates As per IS codification the parameters which were determined are reducing moderately as the amount of aggregates which are recycled is being raised

scholarly journals Quality Improvement of Recycled Aggregate Concrete using Six Sigma DMAIC Methodology

2020 ◽  
Vol 5 (6) ◽  
pp. 1409-1419
Author(s):  
Suhas Vijay Patil ◽  
Balakrishna Rao K. ◽  
Gopinatha Nayak
Keyword(s):  
Six Sigma ◽  
Coarse Aggregate ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Lower Grade ◽  
Test Results ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Concrete Mix

Recycled aggregates (RA) are obtained from construction and demolished waste, laboratory crushed concrete and concrete waste at RMC plants. The concrete made from recycled aggregate is known as recycled aggregate concrete. The use of recycled aggregate is very beneficial to the environment in civil works. Its usage also helps in financial saving as the cost of transportation and production energy cost of natural coarse aggregate (NCA) is reduced. In India, the recycled aggregate application in lower grade concrete work is observed. However, the effect of recycled aggregate on the strength and durability of concrete restricts its use in higher-grade work. This paper presents a series of tests carried out on recycled coarse aggregate (RCA) and recycled coarse aggregate concrete (RCAC) and test results are compared with the NCA and parent concrete made from NCA. Tests were carried out as per IS code and concrete was prepared using a two-stage mixing approach in the concrete mix design. M30 concrete mix of four RCAC samples was tested at 28 days of curing and in comparison with parent concrete, it is found that on an average compressive strength is decreased by 12.89% at 28 days curing. Adhered mortar increases the porosity of the recycled aggregate and forms a weak zone between aggregate surface and mortar. In addition, test results showed the defects in recycled aggregate and helped to identify the area where concentration is necessary to improve the quality of recycled aggregate using six sigma DMAIC methodology. Total of 12 defects were found in the process and raw material. Statistical analysis was used to evaluate the performance of all the mix made with RCA.

scholarly journals Experimental Characterization of Recycled Aggregate Concrete

2019 ◽  
Vol 303 ◽  
pp. 05004
Author(s):  
Khaoula NAOUAOUI ◽  
Azzeddine BOUYAHYAOUI ◽  
Toufik CHERRADI
Keyword(s):  
Compressive Strength ◽  
Developed Countries ◽  
Tourism Industry ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Aggregate Concrete ◽  
Different Types ◽  
Natural Aggregates

The field of construction is evolving rapidly over the last decade. This is justified by the evolution of human activity in various fields mainly tourism, industry … and the aging of several buildings which implies a renovation or a demolition/re-construction. These construction activities involve a large need for aggregates for new construction and a large tonnage of waste from demolitions. In order to remedy this, various stakeholders in the field (suppliers, cement works, research centers, etc.) have valued recycled aggregate concrete (RAC). Recycled aggregates concrete is considered a new type of concrete based on the use of aggregates retrieved from the demolished structures instead of natural aggregates. This replacement affects, for sure, the characteristics of the concrete produced specially the mechanical properties. Developed countries have made a great progress in normalizing the use of recycled aggregates (RA) in concrete implementation as a result of many studies done since 80’s. In Morocco, recycled aggregates do not have any specific standards, and is used mainly in roads and pavements construction. Even if it’s not normalized this use is not recent, in 1999 during the rehabilitation of the expressway road of Casablanca which was severely damaged on both channels, the authorities have opted for the reuse of aggregates instead of reloading the existing pavement with a new one. The study is based on the use of recycled concrete crushed from an old building in Rabat- Morocco as aggregates and compared it with naturel aggregates from Morocco to determinate the effect of this replacement on several characteristics of concrete. This article is aiming to investigate experimentally the effect of RA in concrete using different replacement levels, different types of adjuvant and different percentages of it. The results show that over 30% of replacement, the compressive strength decreases considerably for basic concrete. In order to increase the compressive strength for the RAC with a percentage of replacement over 50%, we used different types of additives (Plasticizer, superplasticizer and new generation superplasticizer) and different percentage of it (0.5%, 1% and 1.5%): We concludes that, for our case, the add of plasticizer gives the best result and that the 1% replacement is the optimum percentage. The tests done on RCA made by plasticizer with different replacement level confirm the results without plasticizer: Compressive strength decreases when the replacement percentage increases.

scholarly journals Concrete produced with recycled aggregates

2012 ◽  
Vol 5 (5) ◽  
pp. 692-701 ◽  
Author(s):  
J. J. L. Tenório ◽  
P. C. C. Gomes ◽  
C. C. Rodrigues ◽  
T. F. F. de Alencar
Keyword(s):  
Coarse Aggregate ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Hardened Concrete ◽  
Specific Mass ◽  
River Sand ◽  
Recycled Coarse Aggregate ◽  
Coarse Aggregates ◽  
Natural Aggregates

This paper presents the analysis of the mechanical and durable properties of recycled aggregate concrete (RAC) for using in concrete. The porosity of recycled coarse aggregates is known to influence the fresh and hardened concrete properties and these properties are related to the specific mass of the recycled coarse aggregates, which directly influences the mechanical properties of the concrete. The recycled aggregates were obtained from construction and demolition wastes (CDW), which were divided into recycled sand (fine) and coarse aggregates. Besides this, a recycled coarse aggregate of a specific mass with a greater density was obtained by mixing the recycled aggregates of the CDW with the recycled aggregates of concrete wastes (CW). The concrete was produced in laboratory by combining three water-cement ratios, the ratios were used in agreement with NBR 6118 for structural concretes, with each recycled coarse aggregates and recycled sand or river sand, and the reference concrete was produced with natural aggregates. It was observed that recycled aggregates can be used in concrete with properties for structural concrete. In general, the use of recycled coarse aggregate in combination with recycled sand did not provide good results; but when the less porous was used, or the recycled coarse aggregate of a specific mass with a greater density, the properties of the concrete showed better results. Some RAC reached bigger strengths than the reference concrete.

scholarly journals Effect of Aggregate Size on Recycled Aggregate Concrete under Equivalent Mortar Volume Mix Design

2021 ◽  
Vol 11 (23) ◽  
pp. 11274
Author(s):  
Haneol Jang ◽  
Jeonghyun Kim ◽  
Alena Sicakova
Keyword(s):  
Mechanical Properties ◽  
Distribution Curve ◽  
Aggregate Size ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Mix Design ◽  
Recycled Aggregates ◽  
Particle Size Distribution Curve ◽  
Aggregate Concrete ◽  
Natural Aggregates

In this paper, the effect of the original aggregate size of the recycled aggregate on the mechanical properties of the recycled aggregate concrete was evaluated. A series of concretes were produced in which natural aggregates, recycled aggregates, and original aggregates in recycled aggregates were matched for a single particle size distribution curve. The replacement levels of recycled aggregate were 25% and 50%, and equivalent mortar volume mix design was applied for recycled aggregate concrete. The results show that the mechanical strength of recycled aggregate concrete increases with increasing original aggregate size. This effect was observed to be greater in concrete using recycled aggregate with a high residual mortar content.

Application of Intensification Approaches on Recycled Aggregate

2013 ◽  
Vol 639-640 ◽  
pp. 372-376
Author(s):  
Jian Yin ◽  
Qi Ling Pang ◽  
Yi Chi
Keyword(s):  
Flexural Strength ◽  
Laboratory Experiments ◽  
Cement Mortar ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Mechanical Agitation ◽  
Aggregate Concrete ◽  
Chemical Solutions ◽  
Strength And Durability

The wasted cement mortar and internal cracks induced by the secondary breaking process existing on/in recycled aggregates lead to significant reductions in the apparent density, strength and durability of recycled aggregate concrete compared to those of natural aggregate concrete. In this study, recycled aggregate intensification approaches was proposed by removing the old cement mortar from recycled aggregate surface through mechanical agitation, and immersing the recycled aggregate in chemical solutions. A series of laboratory experiments were carried out to validate that the proposed approach could improve various performances of the recycled aggregate, as well as the concrete made of it. The testing results showed that through the combination treatment or modification of mechanical and chemical intensification, both of the compressive and flexural strength of the recycled aggregate concrete could be increased to some extent.

scholarly journals Influence of Granite Cutting Waste on Mechanical Properties of Recycled Aggregate Concrete

2021 ◽  
Vol 2070 (1) ◽  
pp. 012165
Author(s):  
Ganesh Naidu Gopu ◽  
M Sri Durga Vara Prasad ◽  
Sugandham Kaumanu ◽  
P Ravi Kumar
Keyword(s):  
Mechanical Properties ◽  
Coarse Aggregate ◽  
Developing Nations ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Fresh Properties ◽  
Normal Concrete ◽  
Aggregate Concrete ◽  
Optimal Values

Abstract Solid waste disposition has been a growing problem in many developed and under-developing nations. Major part of development was constituted by construction and infrastructure; on the contrary these industries also lead to release of carbon dioxide into the atmosphere. To overcome these disadvantages; in this research, recycled aggregates from construction waste and granite cutting waste were adopted as a replacement of coarse aggregate and cement respectively. Mechanical properties of recycled aggregate (RA) concrete are tested by replacing coarse aggregate varying from 0% to 100% with a difference of 25% and cement is replaced with Granite cutting waste (GCW) varying from 0% to 20% with a difference of 5%. Mix designation and fresh properties were also presented. Results were plotted and compared with the normal concrete to predict the most optimal values of the replacement. Mix containing 25% of RA and 15% of GCW replaced has shown a notable difference in strength comparing with the normal aggregate concrete.

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