scholarly journals Experimental Analysis of Demolished Concrete by Using its Coarse Aggregate as Recycling Material

Author(s):  
Sagar M Pawar ◽  
Anil T Babar

Concrete is most widely used in construction material all over the world in view of its compressive strength, Moulding ability, structural ability and economic consideration. Recycling of Demolished concrete aggregate means the process of collection and reusing it in their original form. Use recycled aggregate (RCA) in concrete is helpful for protection of environment and economic point of view. Recycled aggregate are the material for future, as it is used up to 20 % of replacement by natural aggregate available from quarries. This paper gives application of coarse aggregate from recycled demolished concrete when used in M20 mix proportion with different percentage of recycled aggregate replaced with natural one and its result analysed at 7,14, and 28 days of compressive strength.

2020 ◽  
Vol 15 (2) ◽  
pp. 49-54
Author(s):  
Jozef Junák ◽  
Natália Junáková

AbstractThe introductory part of the paper is devoted to the classification of aggregates according to various criteria, one of them is the geographical origin of aggregates. From the point of view of the circular economy, the use of recycled aggregates comes to the fore, mainly from the ecological point of view but also from the economic point of view.The paper summarizes the results of research focused on the variation of the amount of 2 Recycled concrete aggregate fractions in concrete, followed by an evaluation of the effect of the presence of recycled material in the mixture on the selected property, specifically compressive strength. The highest compressive strength 34.7 MPa after 28 days hardening reached sample containing 100% recycled fraction 4/8 mm, and 60% recycled fraction 8/16 mm. This value is only slightly different from the compressive strength of the reference sample (34.4 MPa).


2009 ◽  
Vol 1 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Yong P.C. ◽  
Teo D.C.L

In this rapid industrialised world, recycling construction material plays an important role to preserve the natural resources. In this research, recycled concrete aggregates (RCA) from site-tested concrete specimens were used. These consist of 28-days concrete cubes after compression test obtained from a local construction site. These concrete cubes are crushed to suitable size and reused as recycled coarse aggregate. The amount of recycled concrete aggregate used in this research is approximately 200 kg. Many researchers state that recycled aggregates are only suitable for non-structural concrete application. This research, however, shows that the recycled aggregates that are obtained from site-tested concrete specimen make good quality concrete. The compressive strength of recycled aggregate concrete (RAC) is found to be higher than the compressive strength of normal concrete. Recycled aggregate concrete is in close proximity to normal concrete in terms of split tensile strength, flexural strength and wet density. The slump of recycled aggregate concrete is low and that can be improved by using saturated surface dry (SSD) coarse aggregate.


Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 556
Author(s):  
Muhammad Faisal Javed ◽  
Afaq Ahmad Durrani ◽  
Sardar Kashif Ur Rehman ◽  
Fahid Aslam ◽  
Hisham Alabduljabbar ◽  
...  

Numerous research studies have been conducted to improve the weak properties of recycled aggregate as a construction material over the last few decades. In two-stage concrete (TSC), coarse aggregates are placed in formwork, and then grout is injected with high pressure to fill up the voids between the coarse aggregates. In this experimental research, TSC was made with 100% recycled coarse aggregate (RCA). Ten percent and twenty percent bagasse ash was used as a fractional substitution of cement along with the RCA. Conventional concrete with 100% natural coarse aggregate (NCA) and 100% RCA was made to determine compressive strength only. Compressive strength reduction in the TSC was 14.36% when 100% RCA was used. Tensile strength in the TSC decreased when 100% RCA was used. The increase in compressive strength was 8.47% when 20% bagasse ash was used compared to the TSC mix that had 100% RCA. The compressive strength of the TSC at 250 °C was also determined to find the reduction in strength at high temperature. Moreover, the compressive and tensile strength of the TSC that had RCA was improved by the addition of bagasse ash.


2018 ◽  
Vol 162 ◽  
pp. 02020 ◽  
Author(s):  
Nisreen Mohammed ◽  
Kaiss Sarsam ◽  
Mazin Hussien

Use of Recycled Coarse Aggregate (RCA) in concrete can be described in terms of environmental protection and economy. This paper deals with the mechanical properties of concrete compressive strength, splitting tensile strength, modulus of elasticity, and modulus of rupture. Three kinds of concrete mixtures were tested, concrete made with Natural Coarse Aggregate (NCA) as a control concrete and two types of concrete made with recycled coarse aggregate (50% and 100% replacement level of coarse recycled aggregate). These kinds of concrete were made with different targets of compressive strength of concrete f ’c (35MPa) and (70 MPa). Fifty specimens were tested of the fresh and hardened properties of concrete. The waste concrete from laboratory test cubes was crushed to produce the Recycled Coarse Aggregate used in recycled concrete. A comparative between the experimental results of the properties for fresh and hardened concrete is presented in the paper. Recycled aggregate concrete (RCA) had a satisfactory performance despite the replacement ratios. It was found using the size of Recycled Coarse Aggregate (RCA) of (5-14) mm has quite similar in performance with the same size of Natural Coarse Aggregate (NCA), it is necessary to use high quality of recycled concrete (with low levels of impurities). Recycled aggregate as an alternative to natural aggregates -seems quite successful.


2012 ◽  
Vol 598 ◽  
pp. 635-639
Author(s):  
Zhao Hua Du ◽  
Jie Wang

In this paper, the mixture ratio of recycled concrete and its fundamental mechanics properties have been researched by experiments, which include the mechanical properties of recycled aggregate, the optimum mix design of the recycled concrete, compressive strength tests on concrete specimens using the broken abandoned concrete rubbles as recycled coarse aggregate, the replacement ratios of recycled coarse aggregate by mass to the natural coarse aggregate are 0, 0.3, 0.5, 0.70 and 1.0 respectively. The influences of the replacement ratio of recycled coarse aggregate by mass to the fundamental properties of the recycled concrete such as the compressive strength,and the elastic modulus are discussed and analyzed.and the optimum replacement ratio of recycled coarse aggregate by mass is suggested. These may be references to the applications of recycled concrete in engineering.


2008 ◽  
Vol 385-387 ◽  
pp. 381-384 ◽  
Author(s):  
Wei Wang ◽  
Hua Ling ◽  
Xiao Ni Wang ◽  
Tian Xia ◽  
Da Zhi Wang ◽  
...  

With the increase in the use of recycled aggregate concrete (RAC), it is necessary to clearly understand its behavior and characteristics. In this paper, experimental study on compressive strength of RAC with same water/cement ratio is conducted. Firstly, influence of recycled coarse aggregate contents on cube compressive strength of RAC is studied. Secondly, experiment on time-dependent strength developing process of RAC is conducted with different solidification ages. Finally, based on above experimental investigations, empirical formula for compress strengths of RAC with different ages is presented. The result of this paper is helpful to theoretical analysis and practical engineering design of RAC structures.


2014 ◽  
Vol 605 ◽  
pp. 147-150
Author(s):  
Seong Uk Hong ◽  
Seung Hun Kim ◽  
Yong Taeg Lee

This study used the ultrasonic pulse velocity method, one of the non-destructive test methods that does not damage the building for maintenance of to-be-constructed concrete structures using recycled aggregates in order to estimate the compressive strength of high strength concrete structure using recycled coarse aggregate and provide elementary resources for technological establishment of ultrasonic pulse velocity method. 200 test pieces of high strength concrete 40, 50MPa using recycled coarse aggregate were manufactured by replacement rates (0, 30, 50, 100%) and age (1, 7, 28, 180days), and air curing was executed to measure compressive strength and wave velocity. As the result of compressive strength measurement, the one with age of 180day and design strength of 40MPa was 43.69MPa, recycled coarse aggregate replacement rate of 30% 50% 100% were 42.82, 41.22, 37.35MPa, and 50MPa was 52.50MPa, recycled coarse aggregate replacement rate of 30% 50% 100% were 49.02, 46.66, 45.30MPa, and while it could be seen that the test piece substituted with recycled aggregate was found to have lower strength than the test piece with natural aggregate only, but it still reached the design strength to a degree. The correlation of compressive strength and ultrasonic pulse velocity was found and regression analysis was conducted. The estimation formula for compressive strength of high strength concrete using recycled coarse aggregate was found to be Fc=0.069Vp4.05, R2=0.66


2008 ◽  
Vol 3 (4) ◽  
pp. 130-137 ◽  
Author(s):  
R Kumutha ◽  
K Vijai

The properties of concrete containing coarse recycled aggregates were investigated. Laboratory trials were conducted to investigate the possibility of using recycled aggregates from the demolition wastes available locally as the replacement of natural coarse aggregates in concrete. A series of tests were carried out to determine the density, compressive strength, split tensile strength, flexural strength and modulus of elasticity of concrete with and without recycled aggregates. The water cement ratio was kept constant for all the mixes. The coarse aggregate in concrete was replaced with 0%, 20%, 40%, 60%, 80% and 100% recycled coarse aggregates. The test results indicated that the replacement of natural coarse aggregates by recycled aggregates up to 40% had little effect on the compressive strength, but higher levels of replacement reduced the compressive strength. A replacement level of 100% causes a reduction of 28% in compressive strength, 36% in split tensile strength and 50% in flexural strength. For strength characteristics, the results showed a gradual decrease in compressive strength, split tensile strength, flexural strength and modulus of elasticity as the percentage of recycled aggregate used in the specimens increased. 100% replacement of natural coarse aggregate by recycled aggregate resulted in 43% savings in the cost of coarse aggregates and 9% savings in the cost of concrete.


2018 ◽  
Vol 203 ◽  
pp. 06001
Author(s):  
Muhammad Bilal Waris ◽  
Hussain Najwani ◽  
Khalifa Al-Jabri ◽  
Abdullah Al-Saidy

To manage tyre waste and conserve natural aggregate resource, this research investigates the use of waste tyre rubber as partial replacement of fine aggregates in non-structural concrete. The research used Taguchi method to study the influence of mix proportion, water-to-cement ratio and tyre rubber replacement percentage on concrete. Nine mixes were prepared with mix proportion of 1:2:4, 1:5:4 and 1:2.5:3; water-to-cement ratio of 0.25, 0.35 and 0.40 and rubber to fine aggregate replacement of 20%, 30% and 40%. Compressive strength and water absorption tests were carried out on 100 mm cubes. Compressive strength was directly proportional to the amount of coarse aggregate in the mix. Water-to-cement ratio increased the strength within the range used in the study. Strength was found to be more sensitive to the overall rubber content than the replacement ratio. Seven out of the nine mixes satisfied the minimum strength requirement for concrete blocks set by ASTM. Water absorption and density for all mixes satisfied the limits applicable for concrete blocks. The study indicates that mix proportions with fine to coarse aggregate ratio of less than 1.0 and w/c ratio around 0.40 can be used with tyre rubber replacements of up to 30 % to satisfy requirements for non-structural concrete.


2019 ◽  
Vol 258 ◽  
pp. 04011
Author(s):  
Atur P. N. Siregar ◽  
Emma L. Pasaribu ◽  
I Wayan Suarnita

Coarse aggregate is the dominant constituent in concrete. Aggregate hardness is a variable needed to investigate in determining its effect on the critical stress intensity factors (KIC), dissipated fracture energy (Gf) and compressive strength (fc’) of the concrete. The hardness of coarse aggregate based on Los Angeles abrasion values of 16.7%., 22.6%, and 23.1% was used incorporated with Portland Composite Cement (PCC), and superplasticizer to create specimens. Cubes of 150x150x150 mm were employed to determine the fc’, and four beam sizes: 50x100x350 mm, 50x150x500 mm, 50x300x950 mm and 50x450x1250 mm were engaged to determine KIC and Gf. The fc’ and Gf of specimens manufactured by three different hardness of coarse aggregates were 45, 43, 40 MPa and 89.4, 54.0, 56.3 N/m respectively. KIC of specimens was 138.9, 119.4 and 114.1 MPa.mm1/2 for beam size of 50x100x350 mm; 148.2, 115.8 and 108.8 MPa.mm1/2 for beam size of 50x150x500 mm; 230.9, 183.1 and 157.9 MPa.mm1/2 for beam size of 50x300x950 mm; and 293.2, 248.1 and 244.3 MPa.mm1/2 for beam size of 50x450x1250 mm. Experimental results showed that decreasing hardness of coarse aggregate was found to have significant effect on the fracture toughness rather than on the compressive strength of concrete.


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