Recycled aggregates in concrete aggregate research. Hanson and torben 1986 stated that since 1945, the research on recycled aggregate had been carried out in many countries. Recycled concrete as aggregate for structural concrete. The use of recycled concrete aggregate rca in concrete as partial and full replacements of natural coarse aggregate is growing interest in the construction industry, as it reduces the demand for virgin aggregate.
It is called recycled aggregate which can be produced by concrete crusher. Use of recycled aggregate in concrete can be useful for environmental protection. Pdf the use of recycled aggregates in concrete opens a whole new range of possibilities in the reuse of materials in the building industry. The recycled aggregates can used in the pavement construction. Goonan abstract increased amounts of recycled materials are being used to supplement natural aggregates derived from crushed stone, sand and gravel in road construction. Aggregate strength, gradation, absorption, specific gravity, shape and texture are some of the physical and mechanical characteristics that contribute to the strength and durability of concrete.
Recycled concrete aggregate an overview sciencedirect. Comparison of recycled aggregate treatment methods on the. The compressive strengths of recycled and conventional concretes are similar. The fresh concretes workability, defined as the ease with which concrete can be mixed, transported, and placed, is affected by the interactions of recycled and natural aggregates. Use of recycled fine aggregate in concretes with durable requirements. Recycling recycled aggregate superplasticizer silica fume. The results obtained from the aggregate crushing test, impact test and specific gravity test are within the desirable limit. Recycled aggregate in concrete download ebook pdf, epub. Recycled aggregates and particularly, recycled concrete aggregate substantially affect the properties and mix design of concrete both at fresh and hardened states since it is known by high. In this work, the compressive strength, dynamic elastic modulus, dry shrinkage rate, and chloride ion migration coefficient for five. Also, concrete strength has been reduced by 5% to 25% depending on the percent of the normal aggregate replaced by recycled aggregate and the watercement ratio.
The aggregate should be tested at several substitution rates to determine the optimal rate. Cao, in handbook of alkaliactivated cements, mortars and concretes, 2015. The characteristic of recycled aggregates could be different by its parent concrete because the parent concrete was designed for its purposes such as permeable, durable and high strength concrete. Effects of recycled aggregate on concrete mix and exposure to. Article information, pdf download for studies on recycled aggregatesbased. By collecting the used concrete and breaking it up, recycled concrete aggregate rca is created fig. The use of recycled aggregates in earth and road construction is more common, though also this use. This site is like a library, use search box in the widget to get ebook. Recycled concrete aggregates construction aggregate. Reagg is a major supplier of crushed stone products, recycled concrete, riprap, fill materials, sand, gravel, topsoil, millings, cold patch, mulch, salt, lime, erosion control products and other materials. Concrete made with such recycled concrete aggregate is called recycled aggregate concrete rac. Recycled aggregates are the materials for the future. Paper reports the basic properties of recycled fine aggregate and recycled coarse aggregate.
Recycled concrete aggregates free download as powerpoint presentation. Jun 25, 2019 variations of slump and unit weight of fresh concrete with respect to aggregate concentration are presented in figure 4. Journal of civil engineering and management volume 19, 20 issue 6. Recycled aggregate concrete structures jianzhuang xiao. There are many testing based on the recycled aggregate have been carried out all around the world. Download as ppt, pdf, txt or read online from scribd. This paper focuses on coarse rca which is the coarse aggregate from the original concrete that is created after the mortar is separated from the rock which is reused. This research, however, shows that the recycled aggregates that are obtained from concrete specimen make good quality concrete. Nov 15, 2014 it is called recycled aggregate which can be produced by concrete crusher. Pdf high strength concrete using recycled aggregate. Until now, only a small fraction of concrete byproducts is reused as recycled concrete aggregates rca for the manufacture of concrete. Properties of recycled aggregate 510mm not less than 10mm no 1st 2nd 3rd water absorption % recovery percentage % recycled fine aggregate recycled coarse aggregat e powder size of supplied concrete lumps sand gravel cement paste no 1st 2nd 3rd original concrete number of crushing treatment number of crushing treatment. Sustainable normal and high strength recycled aggregate concretes.
Mar 10, 2015 the comprehensive information presented in recycled aggregate in concrete. Critically analysed the globally published data on recycled aggregate standards. Recycled aggregate is defined as aggregate resulting from the processing of inorganic or mineral material previously used in construction bs en 12620, 20. An example of a mix design using recycled aggregates in a pavement application is shown following table. Laboratory of building materials, department of civil engineering. Pdf modulus of elasticity for recycled aggregate concrete. It has been shown that the application of coarse recycled concrete aggregate, as the component materials in the con crete mixtures, it is possible to produce. Many researchers state that recycled aggregates are only suitable for nonstructural concrete application.
Permeability of the recycled aggregate permeability of the new mortar c permeability of the recycled aggregate pdf wml exemption paragraph. Recycled concrete with variable content of recycled fine aggregate. The important characteristics of aggregates for concrete are listed in table 52 and most are discussed in the following section. Self compacting concrete with recycled coarse aggregates. Recycled concrete aggregates are different from natural aggregates and. A number of manufactured and recycled aggregates are readily available in certain localities. This paper presents the effect of rca to concrete and a treatment method utilized to improve the properties of rca, by reducing the amount of the adhered mortar, and therefore the properties of the recycled. The application of recycled aggregate has been started in. The application of recycled aggregate has been started in many construction projects in many european, american and asian countries. In this paper, the effects of various percentages 0%, 25%, 50%, 75%, 100% of recycled aggregate ra on compressive strength of recycled aggregate concrete rac were investigated.
The comprehensive information presented in recycled aggregate in concrete. The use of recycled concrete aggregate rca in concrete as. Pdf this study of structural concrete made with recycled concrete aggregate focuses on two issues. The present paper refers to the concrete recycling subject and, more specifically, to a proposal for greek specifications of recycled concrete aggregates rca with reference to international. Recycled aggregate in concrete civil engineering community. Review article assessment of recycled aggregate concrete parekh d.
Comparison of recycled aggregate and natural aggregate effect of ra on concrete. Increasing the recycled aggregate content reduces the unit weight and density of the concrete, resulting in lighter concrete figure 6. The unit weight of the concrete ranged from 2365 to 2175 kgm 3, depending on aggregate content figure 6. This can be done on the project site or at nearby recycling plants, eliminating the transportation to distant disposal sites and the hauling in of virgin aggregate. Mar 29, 20 by collecting the used concrete and breaking it up, recycled concrete aggregate rca is created fig. Recycled aggregate occurs as either recycled concrete aggregate rca or recycled asphalt pavement rap. Recycling concrete and asphalt has been taking place in the usa since at least the early 1970s nanasy 1972, and by the 1990s was a wellestablished activity. The collected data will also be an essential reference for practicing engineers who face problems concerning the use of these materials in. Recycled aggregate concrete is defined as concrete manufactured with waste materials in order to reduce the negative environmental impact that results from the manufacturing process of cement, achieving a more sustainable product. The durable behaviour of recycled concretes is as good as that of conventional one. Recycled concrete is crushed and the entire aggregate product can be used as a base material according to specifications, therefore generating no waste. Such an effect can be easily retained by using plasticizers. Use of recycled plastics in eco efficient concrete download.
Recycled concrete aggregate rca is generally produced by twostage crushing of demolished concrete, and screening and removal of contaminants such as reinforcement, paper, wood, plastics and gypsum. Only up to 10 to 20 percent fine rca is beneficial. Effects of recycled aggregate on concrete mix and exposure. The unit weights of the 15%, 20%, and 25% mixes were reduced by 8%, 11%, and 11. Click download or read online button to get recycled aggregate in concrete book now. The recycled coarse aggregates rca were sourced from tested and crushed concrete cylinders. The water absorption increased in scc with recycled aggregate was due to the higher water absorption in rca.
Bulk density of aggregate the bulk density of the recycled aggregate, due to a higher porosity of mortar layer, has a lower value than the bulk density of natural aggregates and. International journal of engineering trends and technology. Studies on recycled aggregatesbased concrete major rakshvir. Recycled aggregate an overview sciencedirect topics. Performing organization name and address university of colorado denver campus box 1 1200 larimer street p. This paper focuses on coarse rca which is the coarse aggregate from the original concrete that is created after the mortar is separated from the rock.
Jun 11, 2015 the compressive strength of recycled aggregate concrete was found to range between 18 and 65 mpa, and therefore a prediction equation is proposed for recycled aggregate concrete that considers the ratio and types of recycled coarse aggregates used. As interest in sustainable materials such as recycled aggregate concrete rac rises, effort, it is important to understand the properties of rac that relates to its. Construction materials are increasingly judged by their ecological characteristics. When flexural strength was studied all concrete mixes gave similar to that of traditional concrete. The amount of recycled coarse aggregate used in this research is approximately 125 kg. Abstract in major egyptian cities there is a surge in construction and demolition waste cdw. Review article assessment of recycled aggregate concrete. Ra is used to replace natural aggregate na as coarse aggregate in concrete mixes. Often recycled aggregate is combined with virgin aggregate when used in new concrete. Enhancing mechanical and durability properties of recycled.
Many countries are giving many infrastructural laws relaxation for increase the use of recycled aggregate. Modulus of elasticity of recycled aggregate concrete. In many countries, including australia, recycled concrete aggregates rca have been. Attaining a recycled aggregate concrete mix while reusing tested cylinders would have positive economic. The analysis was focused on the aggregate production for the concrete manufacture. Concrete recycling gains importance because it protects natural resources and eliminates the need for disposal by using the readily available concrete as an aggregate source for new concrete or pavement subbase layers. Volume 31, issue 11, november 2011, pages 23362340. This paper can encourage and further promote the use of recycled aggregate.
Recycled construction and demolition concrete waste as aggregate. Use of recycled plastics in eco efficient concrete. In this work, the compressive strength, dynamic elastic modulus, dry shrinkage rate, and chloride ion migration coefficient for five types of recycled concretes were investigated. Some natural aggregate deposits, called pitrun gravel, consist of gravel and sand that can be readily used in concrete after minimal processing. Read this book on springerlink download preface 1 pdf 39. Pdf recycled aggregate concrete as structural material. When consisting mainly of crushed concrete, it may be classified as recycled concrete aggregate rca. Khatib 6, when 100 percent natural fine aggregate was replaced by recycled fine aggregate, the compressive strength reduced rapidly below 75 percent of the concrete 50mpa with no recycled fine aggregate. The aggregates are categorized by size as coarse and fine aggregate. This site is like a library, use search box in the widget to get ebook that you want. Aggregates for concrete bination of gravels or crushed stone with particles predominantly larger than 5 mm 0. Pimplikar published on 20 download full article with reference data and citations.
Study on utilization of agricultural and industrial wastes in production of cement, concrete, and alternative construction materials. Use of recycled fine aggregate in concretes with durable. The application of recycled aggregate has been started in a large number of construction projects of many european, american, russian and asian countries. Recycled coarse aggregates recycled coarse aggregates. Highlights recycled fine aggregate obtained from crushed waste concrete. Ppt civil project ppt recycled aggregate concrete ashish. For assessing the suitability of using recycled aggregates in pavement construction three test were conducted. Aggregates from natural and recycled sources economic assessments for construction applicationsa materials flow study by david r. This book is a printed edition of the special issue new trends in recycled aggregate concrete that was published in applied sciences download pdf add this book to my library.
Strength and durability evaluation of recycled aggregate. New trends in recycled aggregate concrete mdpi books. Recycled glass aggregate concrete decor magazine vol. Transportation applications of recycled concrete aggregate. Use of industrial, construction and demolition waste will be helpful to graduate students, researchers and concrete technologists. The effect of different aggregate treatment methods on the properties of both the recycled aggregate and the recycled concrete was studied. Nelson, shing chai ngo in 20044 stated that the workability was good and can be satisfactorily handled for 0% recycled aggregate to 80% recycled aggregate and with more percentage replacement of recycled aggregate used in the. The compressive strength of recycled aggregate concrete was found to range between 18 and 65 mpa, and therefore a prediction equation is proposed for recycled aggregate concrete that considers the ratio and types of recycled coarse aggregates used.
Recycled concrete aggregate is considered as the most abundant and used secondary aggregate in concrete production, other types of solid waste are also being used in concrete for specific purposes. Pdf high strength concrete using recycled aggregate anand. After demolition of old roads and buildings, the removed concrete is often considered worthless and disposed of as demolition waste. Study on use of recycled aggregates in pavement construction.