The effects of waste concrete properties on recycled aggregate concrete properties

2013 ◽  
Vol 65 (14) ◽  
pp. 844-854 ◽  
Author(s):  
H. Süleyman Gökçe ◽  
Osman Şimşek
2009 ◽  
Vol 620-622 ◽  
pp. 255-258 ◽  
Author(s):  
Cheol Woo Park

As the amount of waste concrete has been increased and recycling technique advances, this study investigates the applicability of recycled concrete aggregate for concrete structures. In addition fly ash, the industrial by-product, was considered in the concrete mix. Experimental program performed compressive strength and chloride penetration resistance tests with various replacement levels of fine recycled concrete aggregate and fly ash. In most case, the design strength, 40MPa, was obtained. It was known that the replacement of the fine aggregate with fine RCA may have greater influence on the strength development rather than the addition of fly ash. It is recommended that when complete coarse aggregate is replaced with RCA the fine RCA replacement should be less than 60%. The recycled aggregate concrete can achieve sufficient resistance to the chloride ion penetration and the resistance can be more effectively controlled by adding fly ash. It I finally conclude that the recycled concrete aggregate can be successfully used in the construction field and the recycling rate of waste concrete and flay ash should be increased without causing significant engineering problems.


2011 ◽  
Vol 261-263 ◽  
pp. 19-23 ◽  
Author(s):  
Da Xing Qian ◽  
Ying Wei Yun ◽  
Ii Young Jang ◽  
Jong Hoe Kim

Recently reutilization of waste concrete becomes one of the hottest issues in civil engineering field throughout the world. However, most of the concerned research focuses on the RCA (recycled coarse aggregate) by simply crushing waste concrete. In this paper shucking technique is developed to secondary process the simply crushing waste concrete for improving the performance of RCA concrete. Test has been done to demonstrate that performances such as strength, elastic modulus et al. of shucking RCA concrete is better than those of common recycled concrete. Simultaneously, beam specimens are made to test the flexural behavior of shucking RCA concrete. Results showed that the deflection of shucking RCA concrete beam is approximately same with that of natural coarse aggregate concrete beam, which solves current problem that recycled aggregate concrete beam has bigger deflection than common concrete beam. The new shucking technique developed in this paper has many advantages to be applied in practical engineering and it has obvious economic benefits and social effect.


2015 ◽  
Vol 776 ◽  
pp. 53-58 ◽  
Author(s):  
Ni Nyoman Kencanawati ◽  
Jauhar Fajrin ◽  
Buan Anshari ◽  
Akmaluddin ◽  
Mitsuhiro Shigeishi

A large amount of waste concrete generates an environmental problem due to demolition of old concrete structures. To solve this problem, it is necessary to collect recycled aggregate from waste concrete. The conventional recycling technique of recycled aggregate from waste concrete does not indicate a significant quality to be re-used for making a new concrete. We proposed new techniques to produce high grade recycled aggregate by heating-grinding (H-G) method and heating-grinding-acid (H-G-A) method. To ensure the quality of the concrete made from recycled coarse aggregate concrete, the non-destructive evaluation was conducted in this research. High grade recycled aggregate concrete were prepared in advanced using two methods mentioned earlier. Then, new concrete specimens were produced using those types of recycled aggregate concrete. After 28 days curing time, rebound hammer test and ultrasonic pulse velocity test were performed on recycled coarse aggregate concrete to examine the surface hardness and ultrasonic wave velocity of the concrete. Almost similar quality to natural coarse aggregate in terms of density, water absorption, sieve analysis achieved by both H-G recycled coarse aggregate and H-G-A recycled coarse aggregate. However, the surface hardness and ultrasonic wave velocity of H-G-A recycled coarse aggregate concrete is better than those of H-G recycled coarse aggregate concrete. That acid solvent enables to dismantle the cement paste from aggregate surface more effectively, so this types of recycled aggregate shows a better performance than the other one. Continued delamination reduces pores in the interfacial transition zone resulting better bonding mechanism between new cement paste and recycled aggregate surface.


2021 ◽  
Vol 42 ◽  
pp. 2785-2788
Author(s):  
Sameh B. Tobeia ◽  
Mustafa M. Khattab ◽  
Hasanain H. Khlaif ◽  
Mohammed S. Ahmed

2018 ◽  
Vol 760 ◽  
pp. 176-183 ◽  
Author(s):  
Tereza Pavlů

The main aim of this contribution is comparison the properties of fine aggregate concrete with partial replacement of sand by fine recycled aggregate. The fine recycled aggregate originated from two different sources. The main topic of this article is the study of influence of the origin of FRA to fine aggregate concrete properties. The compressive strength, flexural strength and freeze-thaw resistance were tested. The mechanical properties and weight were examined after 28 and 60 days and after 25, 50, 75 and 100 cycles of freeze-thaw. Partial replacement of sand was 25 and 50 % for all these tests. The properties were investigated by using prismatic specimens.


2013 ◽  
Vol 671-674 ◽  
pp. 1852-1855
Author(s):  
Zuo Shan Li ◽  
Li Hui Xie ◽  
Jun Ya Luo ◽  
Xiang Chao Zhang

The experimental investigation of the preparation process of recycled aggregate concrete (RAC) using the waste concrete as recycled aggregate concrete (RCA) was reported. By conducting a series of laboratory experiments, the crushing and sieving procedure of wasted concrete to produce RCA were studied, the RACs with different strengths were designed, the strengths of hardened concrete were investigated. The results indicated that the representative strength for designing C10, C15 and C25 grade RAC using RCA were 11.3, 16.2 and 27.3 Mpa, respectively. The results gained in this study prove to be a valuable building materials using RCA for doveloping the RAC. Recycling and reuse of building wastes have been found to be an appropriate solution to the problems of dumping hundred of thousands tons of debris accompanied with shortage of natural aggregates.


2005 ◽  
Vol 2 (2) ◽  
pp. 49
Author(s):  
Ahmad Ruslan Mohd Ridzuan ◽  
Azmi Ibrahim ◽  
Abdul Manaff Mohd Ismail

The effects of using crushed waste concrete as course aggregates upon compressive strength and carbonation were investigated. Waste concrete cubes, which had been tested for compressive strength in compliance with construction specification, were crushed and utilized as coarse recycled aggregates in new concrete. It is important to mention that, in order to simulate the real life conditions, waste concrete with very minimal information about its originality was used in its natural moisture condition. Tests on the aggregates showed that the recycled concrete aggregates have lower specific gravity and bulk density but have higher water absorption capacity than the natural aggregates. The resistance to mechanical actions such as impact and crushing for recycled concrete aggregates is also lower. Concrete mixes with design strength of 30 N/mm2, 35 N/mm2 and 40 N/mm2 were prepared using this recycled aggregates as coarse aggregates and tested. From the strength point of view the recycled aggregate concrete compared well with natural aggregate concrete. Therefore, it could be considered for various potential applications. With respect to resistance to carbonation the recycled aggregate concrete shows comparable performance.


2014 ◽  
Vol 665 ◽  
pp. 155-158
Author(s):  
Yan Rong Gao ◽  
Qun Xia ◽  
Jin Cai Feng

Experimental research on carbonation resistance of recycled aggregate concrete was conducted. Two kinds of recycled aggregates were considered, which were from road waste concrete blocks and waste concrete specimens in lab. The test results showed that the carbonation depth of RAC using the aggregates above increased by 11%, 17% at 28d compared with ordinary concrete. On the earning data of tests, the relationship between aggregate replacement rate and carbonation depth could be accounted as cubic parabola curve.


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