When durability properties were considered concrete produced with up to 50% of rca could be used in hpc production. This paper deals with the mechanical properties of concrete compressive. Strength reduction of concrete produced from recycled coarse aggregate and natural fine aggregate ranges from 5 to 24%. Recycling of brick aggregate concrete as coarse aggregate. Structural behaviour of composite members with recycled. Properties of recycled concrete aggregate under different curing. Concrete aggregate collected from demolition sites is put through a crushing machine. The properties of rca were compared with state road authority requirements to. Properties of concrete with coconut shells as aggregate. Durability and performance characteristics of recycled. Influence of the shape of the natural aggregates, recycled. Fly ash based geopolymer concrete with recycled concrete. It is commonly believed that rca has high porosity, low apparent density, and high water absorption. However, rubber aggregates with smaller or continuously graded particle sizes are shown to have higher strengths and water permeability resistance.
The comparative study is made thereafter on fresh and hardened properties of concrete made with natural aggregates and recycled coarse aggregates, hence in. Generally it is seen a lot of difference in physical properties such as. Reduction in material cost, transportation cost and overall cost of the project. Jan 01, 20 the properties of rac containing both fine and coarse recycled aggregate are inferior to those of rac containing only coarse recycled aggregate. Feb 15, 2014 the physical, mechanical and durability properties of the recycled aggregates concretes and conventional concrete were analyzed. Recycled aggregates composed of original aggregates and adhered mortar. Recycled sand will be avoided, due to its absorption capacity, which would no doubt produce a shrinkage effect. Aggregates, compressive strength, concrete, durability, recycling. Mechanical properties of concrete containing recycled materials. The physical properties of rap aggregates were compared with similar concretes made with natural aggregate. Concrete mixes of m40 grade using recycled aggregate were designed as per the suggested guidelines of is. Properties of the recycled aggregate can be tested in accordance with requirement set in bs812 to investigate suitability of the aggregate in new concrete.
There is strong evidence that aggregate type is a factor in the strength of. Through the influence on the watercement ratio porosity and consistency, an increased water absorption of recycled aggregate. 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. Conventional stone crushing equipment can be used, and new equipment has been developed to reduce noise and dust. How are recycled aggregates covered by existing standards. Water absorption of recycled aggregate influence both fresh and hardened concrete properties.
Workability of recycled aggregate concretes is affected by the absorption capacity of the recycled aggregates. The employ ment of different qualities of recycled aggregate in concrete production brings about an increase in the compressive strength variation coefficient 21. Oct 22, 2019 this study examines the use of recycled aggregates in geopolymer concrete as a substitute for coarse aggregates. 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 aggregate concrete rac. In this paper, the permeability properties of fine recycled aggregate concrete are presented. This thesis addresses the importance of using recycled aggregate in concrete. Recycled plastics as coarse aggregate for structural. This paper presents the effect of silica fume sf on earlyage and longterm mechanical properties of recycled aggregate concrete containing slag. Aggregate concrete formed with airdried reusing aggregate and reusing aggregate concrete prepared with saturated surface dry ssd recycling aggregate. Effect of recycled aggregate on mechanical and durability. Mechanical properties of recycled aggregate concrete produced. At older ages, the recycled aggregate concrete with a lower 50 51 watercement ratio exhibits a higher strength. The goal of this research is to study the mechanical properties of recycled shredded rubber particles extracted from scrap tires in concrete to introduce a sustainable waste management system and subsequently to reduce the use of nonrenewable resources in concrete.
The results showed that the mix with 25% recycled aggregates and 5% microsilica presented comparable performance to that of the plain concrete, while using a higher microsilica content negatively affected the rheological properties. Rac mixes are prepared with each source of rca separately. Recycled aggregate materials produce harsh mixes with lower workability than natural aggregates. Properties of recycled concrete aggregate under different. Recycled aggregate concrete is concrete product produced with recycled aggregate to replace part or whole of natural aggregate. In this study, research was conducted on the mechanical and durability characteristics of concrete using recycled aggregate, after developing. This understanding can only be gained through extensive testing and observation. Improvement of recycled concrete aggregate properties by. In this paper, uniaxial compression tests were carried out for recycled aggregate concrete with water cement ratios of 0. In this circumstance instead of recycling it repeatedly, if it is utilized to prepare aggregates for concrete, it will be a boon to the construction industry.
Crushing facilities accept only uncontaminated concrete, which must be free. Fatigue durability of stabilized recycled aggregate base. Lifecycle assessment lca of concrete with recycled. Recycled aggregate posses relatively lower bulk density, crushing and impact values and higher water absorption as compared to natural aggregate. Recycled plastics as coarse aggregate for structural concrete. Recycled concrete aggregates are different in many ways from virgin aggregates as shown in table 1. Durability properties of repeated recycled coarse aggregate concrete. Use to produce recycled aggregate concrete incorporating milled waste glass. Acceptable recycled coarse aggregates are relatively easy 32 to produce from concrete. Influence of recycled aggregate on concrete properties 1. Generally rca is different from natural aggregate so that the properties of recycled aggregate concrete rac, which employs rca as coarse aggregates, are also different from those of ordinary concrete which employs natural aggregates 711. The compressive strength of recycled aggregate concrete is relatively lower up to 15% than natural aggregate concrete.
Characterization study on recycled coarse aggregate for its. The water absorption capacity of coarse recycled aggregate is about two times or more than natural coarse aggregates. The gradation curves of the aggregates are presented in figure 1. Recycled concrete aggregate research papers academia.
Use of recycled aggregates in concrete a paradigm shift. Various properties of rca to be tested before its utilization in concrete include adhered mortar content, density, and method of recycling, water. Recycled aggregate is well graded as natural aggregate. Therefore, recycled aggregate concretes with high 45 46 47 substitutions degree have minor differences in their compressive strength for different 48 49 watercement ratios. The results were compared with brick aggregate concrete. These effects on the properties of recycled aggregate concrete would be reduced if recycled coarse aggregate was used in combination with virgin aggregates. Fine rca has very high water absorption values up to % and high cohesion, which makes quality control of the concrete very difficult. To predict the behavior of concrete under general loading requires an understanding of the effects of aggregate type, aggregate size, and aggregate content. By and large, strength of concrete produced from crushed concrete aggregate is lower than concrete made using natural aggregate. Rt mixtures exhibited on the average 22% higher modulus of elasticity compared to rf mixtures. Experimental research on mechanical properties of recycled. Experimental analysis of properties of high performance. Recycled concrete as aggregate for structural concrete production.
The britisheuropean harmonised product standard, bs en 12620, for aggregates for concrete, makes no distinction, in terms of properties covered, between. Properties of recycled aggregate concrete made with. The results showed that considering mechanical properties, the 100% natural coarse aggregates replacement would be possible when rca were produced from original concrete with a minimum compressive strength of 60 mpa. Crushed aggregate nca and recycled aggregate from concrete crushed rac,since the shape of the aggregates generally determines the mechanical properties. Pdf mechanical properties of recycled aggregate concrete. Enhancing mechanical and durability properties of recycled.
International journal of engineering trends and technology. However, rubber aggregates with smaller or continuously graded particle sizes are shown to have. In the present study the influence of recycled coarse aggregate rca obtained from three different sources having different ages of structures are on the properties of recycled aggregate concrete rac are investigated. Influence of recycled aggregate and rubber aggregate as. Concrete manufactured from recycled aggregates or a combination of recycled and conventional aggregates such as sand, gravel, or crushed stone. There is an increase in the drying shrinkage of concrete made with recycled aggregates as compared with the same concrete made with virgin aggregates.
Influence of treatment methods on recycled aggregate concrete. It was seen that ssd ra have the lower compressive strength and the reason behind this anomaly is loss of adsorbed water in presoaked aggregate in fresh concrete 21. The quality of aggregates made of recycled concrete affects directly the properties of new concrete mixes. There are four different recycled aggregate rate to respectively produced 6. A study on the properties of recycled aggregate concrete.
The main objective of this paper is to study the tensile strength properties of recycled aggregate concrete rac with and without pozzolanic materials. Magazine of concrete research, volume 69, issue 24, 1 dec 2017 12881295. Its a lower density, elastic modulus, strength and a higher water absorption capacity. E125 chapter 1introduction hydraulic cement concrete is a cement and water paste in. Recycled fine aggregates tend to be more angular than what is 31 preferred for making quality concrete. The size distributions of fa, nca, and rca were within the astm limits, as shown in figure 1. Recycled aggregates are mainly consists of coarse natural aggregate and old cement mortar. Mechanical properties of recycled aggregates concrete. Pdf properties of concrete with recycled aggregates as. This paper presents a laboratory investigation of the geotechnical properties of recycled concrete aggregate rca. In view of the advantages of concrete filled steel tubular columns, recycled aggregate concrete filled steel tube racfst, in which the natural aggregates are partly or totally replaced by the recycled aggregates, has been investigated to advance the application of rac. Moreover, concrete recycling is an effective way for the. Some recycled aggregate properties, such as dimensions, resistances and water absorption are investigated.
Mechanical properties of recycled aggregate concrete containing. Khan, evaluation of mechanical properties of recycled aggregate concrete 2005. Recycled aggregate and a carbon tax are found to be effective ways to. New standards should be introduced for recycled aggregates so that these materials can be used successfully in future. But the overall performance of recycled aggregate concrete with 50% slag was good. Mechanical properties of recycled aggregate concrete at. Apart from above mentioned waste materials and industrial by products, few studies identified that coconut shells, the agricultural by product can also be used as aggregate in concrete. Mechanical and freezing cycles properties of geopolymer. Comparison of typical virgin aggregate and recycled concrete. Concrete with rubber particles of larger size tends to have a higher workability and fresh density than that with smaller particle sizes. Fine recycled aggregates are also used to replace natural sand however this isnt as. Testing of capillary absorption was carried out on the series of three specimens in the age. Effect of recycled aggregates on mechanical properties of.
Maximum properties of recycled coarse aggregate have shown good with a little variation. Recycled concrete, or crushed waste concrete, is a feasible source of aggregates and an economic reality, especially where good aggregates are scarce. Therefore, use of recycled concrete aggregate showed acceptable performance with respect to mechanical properties. A significant reduction in the properties of recycled aggregate concrete rac made of 100% rca was seen when. Properties and characteristics of recycled concrete aggregate a concrete pavements strength and performance is very dependent on the aggregates used to produce the concrete. Durability study for normal grade concrete with recycle. Pdf durability of recycled aggregate concrete miquel. This research demonstrates that rubber particle size affects concrete workability and water permeability to a greater extent than fresh density and strength. Crushed concrete aggregates properties and uses of recycled. Effect of strength properties of recycled aggregate concrete. Flexural strength of the recycled aggregate concrete is almost 85% and 80% of natural aggregate concrete. Effects of recycled concrete aggregate on the fresh.
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. The recycled coarse aggregate will invariably have lower specific gravity and higher absorption than the original aggregate, due to the presence of cement paste. The density and absorption capacity of recycled aggregates are affected by adhered mortar and they. The recycled aggregates were added with their natural moisture and replaced different percentages of the coarse aggregates 0%, 20%, 50% and 100%. Dec 01, 20 the recycling of concrete, bricks and masonry rubble as concrete aggregates is an important way to contribute to a sustainable material flow. Sep 23, 2019 influence of recycled fine aggregate on microstructure and hardened properties of concrete authors. Ravi kumar, subash chandra bose gurram, ashwani kumar minocha source. Pdf mechanical properties of recycled aggregate concrete at. Recycled concrete when a structure made of demolished or renovated concrete is called recycled concrete. It was found that a mixture containing only 4% cement, 4% fly ash, and 92% recycled aggregate by weight achieved a compressive strength of about 5 mp a 725 psi, a split tensile strength of about 0. The crushing procedure and the dimension of the recycled aggregate. Mixes with 10%, 30%, 50% and 100% by volume replacement of fine natural aggregates fna with fra were produced and tested for water. The properties of recycled aggregate, such as specific gravity, absorption.
The unique properties of recycled aggregates provides, superior compaction and constructability. Properties of recycled concrete aggregate under different curing conditions. A comparative study on the strength characteristics of recycled aggregate concrete made with ordinary portland cement and portland pozzolana cement is. Research on the mechanical properties of recycled aggregate. Influence of amount of recycled coarse aggregates and production. Recycled aggregate has rough textured, angular and elongated particles where natural aggregate is smooth and rounded compact aggregate. Evaluation of mechanical properties of recycled aggregate concrete. Okafor 2010 study focused on the replacement of aggregates with rap. In the present study the recycled plastics were used to prepare the coarse aggregates thereby providing a sustainable option to deal with the plastic waste 10. The paper further discusses observed fresh and hardened concrete properties of both recycled and conventional aggregates, and examines specific implications for satisfactory performance of the recycled product for recreational and nonstructural construction applications. Pdf this research presents an experimental investigation on the engineering properties of concrete prepared with crushed tiles as recycled.
Use of recycled coarse aggregate rca in concrete can be described in terms of environmental protection and economy. Crushed concrete aggregates properties and uses of. Nov 15, 2014 its a lower density, elastic modulus, strength and a higher water absorption capacity. Recycling waste concrete as source for the production of new concrete can help control environmental pollution and the problem of depleted natural aggregates. The limited reuse of recycled concrete aggregates rca, even partially, instead of natural aggregates, can be explained by the influence on the properties of fresh and hardened new rcabased concretes.
Pdf the influence of recycled concrete aggregate on the. The physical properties of recycled aggregates depend on both adhered mortar quality and the amount of adhered mortar. In addition, since recycled aggregates require a more amount of water than natural aggregate, shrinkage issue could be a problematic to use rac in practically. 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. The concrete specimens were exposed to two different environments standard. Compressive strength is the basic mechanical properties and one of the indicators to determine the performance of a concrete. Durability of crushed fine recycled aggregate concrete. In addition, the effect of recycled aggregate and microsilica on the microstructure of mixes were examined. Jan 15, 2018 the modulus of elasticity of the recycled aggregate concretes was reduced when the recycled aggregates percentage increased except for the case of rt100 in which it increased by 9%.
Construction and demolition wastes are produced every day around the world. Using normal distribution, the probability distribution function pdf and cumulat. The recycled aggregates obtained from waste concrete are more angular and have higher absorption and specific gravity than natural coarse aggregates and it resulted in increased strength and improved load carrying capacity. Pdf geotechnical properties of recycled concrete aggregate. Recycled aggregate concrete is in close proximity to normal concrete in terms of split tensile strength, flexural strength and wet density. Properties of recycled aggregate concrete springerlink. Thus the idea of using recycled concrete aggregate in new concrete production. Properties of pervious concrete incorporating recycled. There are many recycling plants across the world, but as plastics are recycled they lose their strength with the number of recycling. Two different qualities of recycled aggregates were used by fernando et al.
To assess the mechanical performance, compressive strength, tensile strength, and flexural strength were measured for 20 mixing designs and their relationships with suitable convergence were obtained. Recycled concrete as aggregate for structural concrete. Mpa cement fact sheet 6 use of recycled aggregates in concrete. The fra used come from demolished concrete of known properties. The main difference between recycled concrete aggregate rca and natural aggregate na is the mortar adhered on rca. Pdf properties of highworkability concrete with recycled. This paper presents an experimental research on mechanical properties of recycled aggregate concrete rac at low and high waterbinder wb ratios. Recycled construction and demolition concrete waste as aggregate. Mechanical properties of demolishing waste 4, compressive strength 5, effect of fly ash 18, effect of cement proportion 21, effect of recycled aggregates on mix design 22, and durability. Recycled aggregate concrete showed slight increase in coefficient of permeability and chloride diffusion coefficient than control concrete. Pdf properties of recycled aggregate concrete reinforced with. Study report sr101 effect of recycled concrete aggregate.
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