scholarly journals Experimental Investigation on Self Compacting Concrete Using Recycled Aggregate

Author(s):  
N. Uday Kiran ◽  
S. Hanmanthu ◽  
C. Govardhan

In the present work, an experimental investigation was carried out on self-compacting concrete made with various replacement levels of recycled coarse aggregate. The main aim of the experimental work is to know the suitability and effects of recycled aggregates in SCC. Self-Compacting Concrete is a type of concrete which does not need any kind of vibration or compaction. In the present experimental work, the behaviour of concrete made with recycled aggregates is evaluated and compared with the traditional concrete in which the coarse aggregate is replaced with recycled aggregate by 0%, 50%, and 100% respectively. Mechanical properties of the concrete were evaluated in its fresh and hardened conditions.

Construction is the one the fast growing field in the worldwide. There are many environmental issues connected with the manufacture of OPC, at the same time availability of natural coarse aggregate is getting reduced. Geopolymer binder and recycled aggregates are promising alternatives for OPC and natural coarse aggregates. It is produced by the chemical action of inorganic molecules and made up of Fly Ash, GGBS, fine aggregate, coarse aggregate and an alkaline solution of sodium hydroxide and sodium silicate. 10 M sodium hydroxide and sodium silicate alkali activators are used to synthesis the geopolymer in this study. Recycled aggregates are obtained from the construction demolished waste. The main focus of this work is to find out the mechanical properties of geopolymer concrete of grade G40 when natural coarse aggregate(NCA) is replaced by recycled coarse aggregate in various proportions such as 0%, 10%, 20%, 30%,40% and 50% and also to compare the results of geopolymer concrete made with recycled coarse aggregates(RAGPC) with geopolymer concrete of natural coarse aggregate(GPC) and controlled concrete manufactured with recycled aggregates(RAC) and controlled concrete of natural coarse aggregates(CC) of respective grade. It has been observed that the mechanical properties are enhanced in geopolymer concrete, both in natural coarse aggregate and recycled coarse aggregate up to 30% replacement when it is compared with the same grade of controlled concrete.


2011 ◽  
Vol 477 ◽  
pp. 280-289 ◽  
Author(s):  
Shao Wei Yao ◽  
Zhen Guo Gao ◽  
Chang Rui Wang

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.


This article mainly focused on the influence of recycle coarse aggregate and manufactured sand on the properties of self compacting concrete (SCC). The main purpose of this research is reuse of recycled aggregate in SCC and also to reduce use of fine aggregate by replacing manufactured sand. The SCC mixtures were prepared with 0, 25, 50, 75 and 100% replacement of recycle coarse aggregate in natural coarse aggregate and M-Sand in fine aggregate with a Water/Binder ratio of 0.36. Different test covering fresh properties of these SCC mixtures were executed the results were compared with EFNARC guidelines and IS 10262:2019. The feasibility of utilizing recycled aggregate and M-Sand in self compacting concrete has been examined and found that it is suitable for concrete.


Author(s):  
Suhas Vijay Patil ◽  
Balakrishna Rao K. ◽  
Gopinatha Nayak

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.


2021 ◽  
Vol 11 (13) ◽  
pp. 6028
Author(s):  
P. Jagadesh ◽  
Andrés Juan-Valdés ◽  
M. Ignacio Guerra-Romero ◽  
Julia M. Morán-del Morán-del Pozo ◽  
Julia García-González ◽  
...  

One of the prime objectives of this review is to understand the role of design parameters on the mechanical properties (Compressive and split tensile strength) of Self-Compacting Concrete (SCC) with recycled aggregates (Recycled Coarse Aggregates (RCA) and Recycled Fine Aggregates (RFA)). The design parameters considered for review are Water to Cement (W/C) ratio, Water to Binder (W/B) ratio, Total Aggregates to Cement (TA/C) ratio, Fine Aggregate to Coarse Aggregate (FA/CA) ratio, Water to Solid (W/S) ratio in percentage, superplasticizer (SP) content (kg/cu.m), replacement percentage of RCA, and replacement percentage of RFA. It is observed that with respect to different grades of SCC, designed parameters affect the mechanical properties of SCC with recycled aggregates.


2011 ◽  
Vol 147 ◽  
pp. 288-292 ◽  
Author(s):  
Yong Taeg Lee ◽  
Seong Uk Hong ◽  
Hyun Suk Jang ◽  
Sang Ki Baek ◽  
Young Sang Cho

National effort to recycle construction waste as structural concrete usage of high economic value is ongoing, but performance rate of recycling is a low-level due to a lack of awareness on the recycled aggregates. Accordingly, the goal of this study was to verify the structural applicability of recycled aggregates. This study compared a compressive strength based on the replacement ratio of natural aggregate and recycled aggregate, and analyzed a correlation of wave velocity due to the increase in compressive strength under the same condition. The 『design standard strength – replacement ratio of recycled coarse aggregate』 was set to total 12 combinations by applying 0, 30, 50, 100[%] replacement ratio of recycled coarse aggregate to 21, 27, 35[MPa] to the design standard strength. During the experiment of fracture strength, strength degradation due to the replacement rate of recycled coarse aggregate did not occur, and it was found that the wave velocity also increased along with an increase in strength due to the age of recycled coarse aggregate concrete.


2011 ◽  
Vol 368-373 ◽  
pp. 2185-2188
Author(s):  
Ping Hua Zhu ◽  
Xin Jie Wang ◽  
Jin Cai Feng

The properties of recycled coarsee aggregates from repeatedly recycling waste concrete were determined. In this study, five series of concrete mixtures using coarse and fine natural aggregates were prepared, which have the same objective slump value from 35mm to 50mm and different compressive strengths ranging from 25MPa to 60 MPa. These five concretes were crushed, sieved, washed with water, hot treatmented at 300°C before they were used as recycled aggregates. After that, recycled aggregate concrete (RAC) was produced with an objectively compressive strength of 30MPa, in which the recycled coarse aggregate was used as 30%, 70% and 90% replacements of natural coarse aggregate and recycled fine aggregate as 10%, 20%, and 30% replacements of natural fine aggregate. After that, these recycled concretes were used as second recycled aggregates to produce RAC with the same objectively compressive strength of 30MPa. The physical properties of coarse aggregates including apparent density, water absorption, attached mortar content and crushing value were tested and their mineral characteristics were analyzed. The results showed that the quality of recycled coarse aggregates from twicely recycling waste concrete reached the requirements from structural concrete.


2019 ◽  
Vol 28 ◽  
pp. 096369351988512 ◽  
Author(s):  
Yunyang Wang ◽  
Bingchen Zhao ◽  
Guang Yang ◽  
Yandong Jia ◽  
Lijun Yang ◽  
...  

The effect of recycled coarse aggregate (RCA) on the fresh and hardened properties of C40 self-compacting concrete (SCC) was investigated in this paper. The slump, T 500 (the time needed for SCC to spread into a round configuration with a nominal diameter of 500 mm), the slump flow and the flow time of fresh C40 SCC as well as the compressive strength and modulus of elasticity of hardened C40 SCC were studied. The modulus of elasticity of C40 SCC was calculated by theoretical formula, and the calculated values were compared with the experimental values. Mechanisms that effect on the C40 SCC properties at fresh and hardened states were also explored. The experimental results showed that the slump values of the C40 SCC are beyond 250 mm. The C40 SCC with RCA replacement content of 50% showed the highest slump value of 275 mm. All T 500 values of the C40 SCC are within 5 s. The slump flow of the C40 SCC slightly increases with the increase of replacement content of the RCA. In contrast, the compressive strength and modulus of elasticity of the C40 SCC slightly decrease with the increase of replacement content. The experimental values of modulus of elasticity are lower than that of the calculated values. Submerged in water before mixing of RCA leading to the slump flow of the C40 SCC increases with the increasing replacement content of the RCA. The old cement mortar attached to the RCA surface is the main reason that weakens the mechanical properties. The lower amount of coarse aggregate and the higher amount of cement paste attribute to the lower values of modulus of elasticity. This study implied that RCA can be effectively used in the production of C40 SCC without any significant sacrifice on workability and mechanical properties.


2013 ◽  
Vol 639-640 ◽  
pp. 399-403
Author(s):  
Ai Guo Zhou ◽  
Jian Yin ◽  
Wei Min Song ◽  
Yi Chi

It is studied the effect of binder quantity, water binder ratio on properties of self-compacting concrete made with recycled coarse aggregates. It can be prepared C50 self-compacting concrete made with recycled coarse aggregate by adjusting send proportion, binder quantity, and mixing mineral additive. For example, when the binder quantity is 600 kg/m3, water binder ratio is 0.28, the flexural strength and compressive strength at 28 days of self-compacting concrete made with recycled coarse aggregates are 9.07 MPa and 68.47 MPa respectively.


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