Evaluation of Concrete Strength Made with Recycled Aggregate (original) (raw)
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Investigation of concrete properties using recycled waste concrete aggregate
Periodicals of Engineering and Natural Sciences (PEN), 2023
There are several environmental, economic, and energy reasons why RC is gaining popularity around the world. Key environmental problems include the potential for groundwater contamination due to the washing out of fresh concrete brought back from project sites, as well as the loss of natural sources of high-quality aggregate materials. The RC concrete (RCA) impact on the fundamental characteristics of traditional concrete is investigated besides the effect of different ratio effects of water-cement (w/c). The concrete as crushed rubble obtained from several Iraqi demolition sites and landfills is utilized to examine the properties of (RCA). This work utilized sand as natural, and concrete as crushed from various sources as aggregates around Baghdad city. A total of forty-five concrete mixtures were cast into nine groups. Groups were created to examine the impact of recycled coarse aggregate (CA) quality/content, dosage of cement, and w/c ratio. Strengths of compressing and splitting, and modulus of elastic tests were conducted. The findings demonstrated that the concrete rubble (CR) may be turned into recycled aggregate (RC) and utilized in the concrete manufacturing with qualities adequate for the vast majority of structural concrete applications in Iraq. Furthermore, the concrete strength has decreased by 6% to 30%, depending on the proportion of RC utilized to replace natural aggregate and the w/c ratio.
STUDY ON STRENGTH OF CONCRETE BY USING RECYCLED AGGREGATE FROM DEMOLITION WASTE IN CONCRETE
Concrete waste is generated whenever any demolition activities take place. Among various types of demolished waste materials, concrete waste accounts for about 50% of the total waste generated. The current practice of dumping construction waste materials for land filling affects the groundwater recharges and land degradation. Recycling concrete waste as recycled aggregate is one of the methods adopted to reduce the environmental impact. The aim of this study is to know the feasibility of using concrete waste as coarse aggregate for making new concrete. Metal coarse aggregate is replaced by recycled coarse aggregate by weight in M25 grade concrete. The Recycled Aggregate Concrete (RAC) specimens were tested for compressive strength, tensile strength and flexural strength and results obtained are compared with the conventional Concrete.
Physical properties and mechanical behaviour of concrete made with recycled aggregates and fly ash
This paper investigates the behaviour of concrete made with recycled constituents. The synergistic use of recycled concrete aggregates and fly ash is addressed. Twelve different concrete mixes were prepared, sampled and tested. Stable correlations emerged between replacement ratios and concrete properties. The suitability of these concretes for structural applications was clearly proved. a b s t r a c t Enhancing the environmental sustainability of human activities and industrial processes is a common challenge in various branches of modern research and technology. Being characterised by a huge demand of both energy and raw materials and by a significant contribution to the global emissions of greenhouse gases (GHGs), the construction industry is fully concerned by this challenge. Particularly, since concrete is the most widely used construction material, several solutions are nowadays under investigation to reduce the environmental impact of its production processes. They often consist of partially replacing ''natural'' constituents (i.e. aggregates, cement, water, fibres) with recycled ones, in view of the twofold objective of reducing both the demand of raw materials and the amount of waste to be disposed in land-fills. However, the formulation of reliable relationships between the main physical and mechanical properties of concrete produced with the aforementioned recycled constituents is still considered as an open issue. This paper is a contribution to such topic. The results of a wide experimental campaign carried out on concretes made using recycled concrete aggregates (RCAs) and fly-ash (FA) in partial substitution of natural aggregates (NAs) and cement (C) are presented and discussed herein. Particularly, concretes charac-terised by variable water–binder ratios and produced with different percentages of RCA and variable the content of FA have been tested. Test results have allowed estimating the time evolution of the compres-sive strength, as well as the tensile strength at 28 days, along with some relevant physical properties, such as permeability and resistance to chloride ion penetration. The feasibility of producing structural concrete made with even significant amounts of the aforementioned recycled constituents and industrial by-products clearly emerges from the experimental results.
Mechanical Properties of Concrete with Recycled Concrete Aggregate and Fly Ash
Recycling, 2021
Recycled concrete aggregate (RCA) collected from the demolition of old reinforced concrete structures can be reused to prepare structural and non-structural concrete, thereby protecting the environment by preserving natural resources. This study explores RCA’s use, collected from the crushed concrete of different building projects in Riyadh, to manufacture fresh self-compacting concrete (SCC) and investigate its properties in the fresh and hardened state. Four SCC mixes were prepared by replacing natural aggregate (NA) with RCA at 0%, 25%, 50%, and 75% replacement levels. The water-cement (w/c) ratio was maintained constant at 0.38 for all the mixes. Slump Flow, J-ring, and V-funnel tests were performed on the SCC mixes in the fresh state, and the compressive strength of hardened concrete was determined after seven, 14, and 28 days. Water absorption and split tensile tests were also carried out for all the mixes. The findings revealed that it is possible to reach compressive strengt...
Experimental Study on Concrete Made of Recycled Coarse Aggregate for Sustainability
International Journal for Research in Applied Science & Engineering Technology, 2021
In the construction industry, sustainable development has become a major concern over the years mainly due to the waste produced during construction, but more significantly, during demolition or destruction of large concrete structures. Due to the day-by-day increasing amount of demolished concrete waste, the idea of recycling such waste to produce aggregate for reuse in construction has been increasingly encouraged, thereby promoting the use of a recycled coarse aggregate as a substitute for the natural coarse aggregate. Reusing the aggregates obtained from demolished waste concrete not only conserves natural virgin aggregate but also reduces the need for landfills, decreases energy consumption and also lead to cost savings. In this study, experimental investigations were based on recycled coarse aggregate (RCA) obtained from crushing waste concrete found at the B.I.T. Sindri campus, Dhanbad, Jharkhand, India. The major focus of the research was obtaining the 28-day compressive strength for concrete with varying RCA content of 0%, 25%, 50%, 75%, and 100%. A total of five mixes with water-cement ratio of 0.44 were utilized for this purpose. The experimental results show that fresh natural coarse aggregate has the highest slump value, thereafter it starts deceasing with increasing the content of recycled coarse aggregate. There was a trend of decreasing strength of the 28th day compressive strength test with increase in the RCA content. However, the 50% RCA concrete mix produced very similar compressive strength to that of the 100% natural coarse aggregate concrete.
India is presently generating construction and demolition (C &D) waste to the tune of 23.75 million tones annually and these figures are likely to double fold in the next 7 years. C&D waste and specifically concrete has been seen as a resource in developed countries. Works on recycling have emphasized that if old concrete has to be used in second generation concrete, the product should adhere to the required compressive strength. Literature survey reveals that compressive strength primarily depends upon adhered mortar, water absorption, Los Angeles abrasion, size of aggregates, strength of parent concrete, age of curing and ratio of replacement, interfacial transition zone, moisture state, impurities present and controlled environmental condition. Some of the studies have suggested the mix design procedure for recycled aggregates in concrete, yet a simple and cost effective method of using demolished concrete, taking into account % adhered mortar and thus calculating mix composition needs to be developed. This paper deals with the review of the existing literature work for the use of recycled concrete as aggregates in concrete in respect of mainly the compressive strength and proposes an approach for use of recycled concrete aggregate without compromising the strength.
Analysis of High Strength Concrete processed from Recycled Concrete Aggregates
International Journal for Research in Applied Science & Engineering Technology (IJRASET), 2021
As everyone is aware of the fact that Natural Coarse Aggregate (NCA) is the main constituent of traditional concrete mixes. Whenever an existing concrete structure is demolished, it produces smashed concrete waste in the large amount. Concrete waste give rise to negative effects on the environment. To evade the environmental pollution and mark effective reuse of the concrete waste as Recycled Aggregates in the place of NCA. This operative initiative provides an opportunity to reduce air pollution and soil exploitation to some extent. Such concrete is sustainable in nature and also eco-friendly to the environment. Also, such waste material will lower the usage of naturally occurring stone to produce NCA and thus various natural energy resources will be safeguarded. This study covers the suitability norms for a material to be used for Recycled Aggregate. In this study the natural aggregate is replaced with recycled aggregate in the different percentages (0%, 25%, 50%). When percentage of recycled aggregate mixed in the fixed proportion as percentage replacement to natural aggregates, it imparts improvement in the property of fresh as well as hardened concrete like, compressive strength & split tensile strength. Laboratory results of this research indicates that the value of compressive strength, tensile strength stress-strain curve & NDT of these mixes drives on decreasing, but at the 25% replacement level, it achieves target mean strength. Hence, for the fundamental concrete mix Natural Coarse Aggregate can be efficiently replaced by the Recycled Aggregate to the range of 25%.
Comparative Study of Concrete Using Recycled Coarse Aggregate
International Journal for Research in Applied Science and Engineering Technology
Recycled coarse aggregate (RCA) is produced by crushing the demolition waste from concrete structures. The construction and demolition waste is primarily used for landfill sites which are causing significant damage to the environment and developing serious problems. The use of the RCAs created from the processing of construction and demolition waste in new construction has become more important over the last two decades as it conserves the non-renewable natural resource of virgin aggregates. With a view to the above needs, the present study is aimed to determine the strength properties of RCA concrete depending on the various content of RCA and to compare them to the strength properties of concrete made with natural coarse aggregates (NCA). The fine aggregates of high FM of 3.0 were used for recycled and natural concrete. After performing the compressive strength test, it was found that concrete made with fully replaced RCA has less strength than concrete made with NCA but not much. So, RCA can be used as a replacement for NCA in concrete production. In addition, full replacement of RCA can be used in structures of less importance such as temporary walls, the base of roads, light traffic roads, pavements in college campuses etc.
Effect of Recycled Aggregate and Fly Ash in Concrete
Waste arising from construction and demolition constitutes one of the largest waste streams within the developed and developing nations. The rapid growth in construction and depleting natural resources demands the recycling and reusing technology to be adopted in construction field. The use of recycled coarse aggregate (RCA) and fly ash (FA) is one of theapproaches towards this need.Use of RCA and FA in concrete can be useful for environmental protection and economical terms. In this experimental study the natural coarse aggregate (NCA) is replaced with RCA at different percentage and the mechanical strength of concrete is tested. In addition the FA is introduced as replacement of Cement.The objective of present study is to determine the sustainability of RCA as an alternate material to NCA and to compare the workability, density and compressive strength result using FA. The mix designing is done for water cement ratio 0.5. Cubes are casted by replacing virgin aggregate and cement with 10%, 20%, 30%, 40% RCA and FA and compressive strength is checked. Obtained results are then used to establish an empirical relationship between the strength of concrete by using percentage of RCA and percentage of FA. Results shows that RCA and FA up to 30% can be used for making concrete.
Experimental investigation on the use of recycled aggregates in producing concrete
Structural Engineering and Mechanics, 2013
Disposal of construction wastes poses major challenge to the municipal administration in the developing countries. At the same time new developments in these countries are unscrupulously exploiting the natural resources. The sustainable development requires judicious and careful utilization of natural resources. In this context, reuse of construction and demolition waste can save the global natural resources to greater extent. In this work the bricks and concrete waste from construction sites were crushed to the desired sizes and mixed in various proportions to study its properties in the concrete both in fresh and hardened states. Six mixes of natural and recycled aggregates were used to make the coarse aggregates for the concrete. From each mix nine cylinders were cast, which were tested at 7,14 and 28 days. The properties of concrete with recycled aggregates were compared with the control mix having natural aggregates. The nominal ratio of cement sand and coarse aggregates were kept at 1:2:4 by weight for all mixes. The tests have shown that concrete with recycled aggregates made from old concrete and brick bats provide greater opportunities for reuse of construction wastes in concrete.