scholarly journals A Study on the Properties of Recycled Aggregate Concrete and Its Production Facilities

2019 ◽  
Vol 9 (9) ◽  
pp. 1935 ◽  
Author(s):  
Jung-Ho Kim ◽  
Jong-Hyun Sung ◽  
Chan-Soo Jeon ◽  
Sae-Hyun Lee ◽  
Han-Soo Kim
Keyword(s):  
Drying Shrinkage ◽  
Quality Standards ◽  
Poor Quality ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Freezing And Thawing ◽  
Construction Waste ◽  
Aggregate Concrete ◽  
Air Volume

In recent years, the amount of construction waste and recycled aggregate has been increasing every year in Korea. However, as the recycled aggregate is poor quality, it is not used for concrete, and the Korean government has strengthened the quality standards for recycled aggregate for concrete. In this study, research was conducted on the mechanical and durability characteristics of concrete using recycled aggregate, after developing equipment to improve the quality of recycled aggregate to increase the use of recycled aggregate for environmental improvements. The results illustrated improvements in the air volume, slump, compressive strength, freezing and thawing resistance, and drying shrinkage. Furthermore, this study is expected to contribute to the increased use of recycled aggregate in the future.

A Review of the Durability of Recycle Aggregate Concrete

2015 ◽  
Vol 744-746 ◽  
pp. 1357-1360 ◽  
Author(s):  
Hong Bo Liu ◽  
Jing Sun ◽  
Xiao Hong Cong
Keyword(s):  
Drying Shrinkage ◽  
Present Situation ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycle Aggregate ◽  
Freezing And Thawing ◽  
Chloride Permeability ◽  
Technical Problems ◽  
Aggregate Concrete ◽  
Related Literature

Analyzing the related literature at home and abroad, this paper summarized the results and shared them with reasearchers involved in the field on the recycled aggregate concrete (RAC). In this paper, the durability of RAC will be described from the following several aspects: absorption, chloride permeability, freezing and thawing resistance, carbonation, the sulfate corrosion resistance, drying shrinkage, creep and abrasion resistance. This paper expounded the present situation and progress in the study of the durability of recycled aggregate concrete.Then, some key technical problems needed to be studied were pointed out and many suggestions were put forward.

Quality Improvement of Recycled Aggregate Concrete

2006 ◽  
Vol 302-303 ◽  
pp. 308-313 ◽  
Author(s):  
Vivian W.Y. Tam ◽  
X.F. Gao ◽  
C.M. Tam
Keyword(s):  
Compressive Strength ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Two Stage ◽  
New Approach ◽  
Aggregate Concrete ◽  
Strength Based ◽  
Mixing Method ◽  
Strength Variability

The developments of recycled aggregate concrete pressing hard in construction activities; however, the limitations on their applications had never being ended. The focus of this paper is: i) investigating the waste management strategy in construction; ii) proposing the two-stage mixing approach (TSMA) to improve the quality of RAC; and iii) experimenting the TSMA and assessing the benefits possibly gained. It proposes a new approach in mixing concrete, namely, the two-stage mixing method, to improve compressive strength of RAC and lower its strength variability. The replacement ratio from zero to thirty is under experiment on their compressive strength. Based upon the experimental results, improvements of 31 % in strength at 28 days with 30 % RA substitute was achieved. The effect can be attributably to the porous nature of the RA and the pre-mix process which can make some pores filled up resulting in a denser concrete and thus leading to higher strength when compared with the traditional mixing approach. Therefore, two-stage mixing approach can open up a wider application of recycled aggregate concrete.

scholarly journals Properties of Concrete Using Treated Low-Class Recycled Coarse Aggregate and Blast Furnace Slag Sand

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 843
Author(s):  
Yuji Miyazaki ◽  
Takeshi Watanabe ◽  
Yuji Yamada ◽  
Chikanori Hashimoto
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Coarse Aggregate ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Hardened Concrete ◽  
Freezing And Thawing ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Furnace Slag

Since high quality natural aggregates are becoming scarce, it is important that industrial recycled products and by-products are used as aggregates for concrete. In Japan, the use of recycled aggregate (RG) is encouraged. Since, strength and durability of recycled aggregate concrete is lower than that of normal aggregate concrete, the use of recycled aggregate has not been significant. In order to improve physical properties of concrete using recycled coarse aggregate, blast furnace slag sand has been proposed. Recently, blast furnace slag sand is expected to improve durability, freezing, and thawing damage of concrete in Japan. Properties of fresh and hardened concrete bleeding, compressive strength, and resistance to freezing and thawing which are caused by the rapid freezing and thawing test using liquid nitrogen is a high loader than the JIS A 1148 A method that were investigated. As a result, concrete using treated low-class recycled coarse aggregate and 50% or 30% replacement of crushed sand with blast furnace slag sand showed the best results, in terms of bleeding, resistance to freezing and thawing.

On Construction Wastes Recycling and its Economy

2013 ◽  
Vol 567 ◽  
pp. 119-122
Author(s):  
Yue Qin Tang
Keyword(s):  
High Performance ◽  
Drying Shrinkage ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Bleeding Rate ◽  
Aggregate Concrete ◽  
Ordinary Concrete ◽  
Easy Bleeding ◽  
Large Water ◽  
Water Absorbability

This paper addresses problems of aggregate concrete of construction wastes, which were featured as large water absorption, quick slump loss, as well as easy bleeding and low strength of concrete. A comparative analysis by experiment between recycled aggregate concrete and ordinary concrete was made on aspects of water absorbability, compressive strength, slump loss, bleeding rate, drying shrinkage and economic efficiency. It has found possible to preparing the recycled aggregate concrete of high performance through the prewetting recycled aggregate. It is concluded that construction wastes can be recycled by obtaining the optimum mole of preparing recycled aggregate concrete of construction wastes and evaluating their reliability on cost-lefficiency and mechanic capability，thus, it also recycled the limited resources and solve some environment problems.

Development and Subjects of Recycled Aggregate Concrete in Japan

2006 ◽  
Vol 302-303 ◽  
pp. 288-300 ◽  
Author(s):  
Yoshio Kasai
Keyword(s):  
Processing Method ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
General Character ◽  
Aggregate Concrete

The quality of RCA is influenced by the processing method and quality of original concrete. The general character of RCA, RCA and TR A 0006-2000(concrete using recycled aggregate) are introduced. The execution of RAC work, examples of real constructions with RAC, recycling of concrete powder originated from production of RAC and barriers of using RAC are discussed.

Influence of Recycled Aggregate on Physical and Mechanical Properties of High Performance Recycled Aggregate Concrete

2011 ◽  
Vol 460-461 ◽  
pp. 764-767 ◽  
Author(s):  
Yi Dong Xu ◽  
Jia Ying Sun
Keyword(s):  
High Performance ◽  
Physical And Mechanical Properties ◽  
Chloride Ion ◽  
Poor Quality ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Ion Permeability ◽  
Negative Effects ◽  
Aggregate Concrete ◽  
Positive Effects

Influence of recycled aggregate on slump, compressive strength and chloride ion permeability of recycled aggregate concrete was investigated. As is shown by the results, although recycled aggregate belongs to the category of poor quality aggregate, the properties of high performance recycled aggregate concrete are not reduced dramatically with the increasing amount of recycled aggregate, for recycled aggregate have both positive effects and negative effects on the properties of recycled aggregate concrete. The high performance recycled aggregate concrete can be developed by double-mixture of ultra fine fly ash and superplasticizer.

scholarly journals Experimental Research on the Wettability of Recycled Aggregate Concrete with Fly Ash

2013 ◽  
Vol 7 (1) ◽  
pp. 232-236
Author(s):  
Yuanchen Guo ◽  
Xue Wang ◽  
Jueshi Qian
Keyword(s):  
Fly Ash ◽  
Moisture Absorption ◽  
Drying Shrinkage ◽  
Absorption Capacity ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Structure Theory ◽  
Replacement Rate ◽  
Aggregate Concrete ◽  
Main Factors

Material adsorption, the reverse process of evaporation diffusion, directly reflects the wettability of materials. Wettability is one of the main factors that affect the drying shrinkage of materials. A device that measures the wettability of recycled aggregate concrete (RAC) with fly ash is proposed in this study based on pore structure theory. The isothermal absorption curve of RAC is examined with different fly ash contents. Results show that as the recycled aggregate replacement rate increases, the moisture absorption capacity of RAC gradually increases. The addition of fly ash improves the porosity of RAC structures and reduces material wettability.

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