Bond, durability and microstructural characteristics of ground granulated blast furnace slag based recycled aggregate concrete

2019 ◽  
Vol 212 ◽  
pp. 578-595 ◽  
Author(s):  
R.K. Majhi ◽  
A.N. Nayak
Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 596
Author(s):  
Yasuhiro Dosho

To improve the application of low-quality aggregates in structural concrete, this study investigated the effect of multi-purpose mineral admixtures, such as fly ash and ground granulated blast-furnace slag, on the performance of concrete. Accordingly, the primary performance of low-quality recycled aggregate concrete could be improved by varying the replacement ratio of the recycled aggregate and using appropriate mineral admixtures such as fly ash and ground granulated blast-furnace slag. The results show the potential for the use of low-quality aggregate in structural concrete.


Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 843
Author(s):  
Yuji Miyazaki ◽  
Takeshi Watanabe ◽  
Yuji Yamada ◽  
Chikanori Hashimoto

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.


Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7497
Author(s):  
Jawad Ahmad ◽  
Rebeca Martínez-García ◽  
Maciej Szelag ◽  
Jesús de-Prado-Gil ◽  
Riadh Marzouki ◽  
...  

Recycled aggregate is a good option to be used in concrete production as a coarse aggregate that results in environmental benefits as well as sustainable development. However, recycled aggregate causes a reduction in the mechanical and durability performance of concrete. On the other hand, the removal of industrial waste would be considerably decreased if it could be incorporated into concrete production. One of these possibilities is the substitution of the cement by slag, which enhances the concrete poor properties of recycled aggregate concrete as well as provides a decrease in cement consumption, reducing carbon dioxide production, while resolving a waste management challenge. Furthermore, steel fiber was also added to enhance the tensile capacity of recycled aggregate concrete. The main goal of this study was to investigate the characteristics of concrete using ground granulated blast-furnace slag (GGBS) as a binding material on recycled aggregate fibers reinforced concrete (RAFRC). Mechanical performance was assessed through compressive strength and split tensile strength, while durability aspects were studied through water absorption, acid resistance, and dry shrinkage. The results detected from the different experiments depict that, at an optimum dose (40% RCA, 20%GGBS, and 2.0%), compressive and split tensile strength were 39% and 120% more than the reference concrete, respectively. Furthermore, acid resistance at the optimum dose was 36% more than the reference concrete. Furthermore, decreased water absorption and dry shrinkage cracks were observed with the substitution of GGBS into RAFRC.


2018 ◽  
Vol 12 (1) ◽  
pp. 430-440 ◽  
Author(s):  
Hongzhu Quan ◽  
Hideo Kasami

Introduction:Although hundreds million tons of concrete wastes have been generated annually in China, the use of recycled aggregate for concrete is limited because of low density and high absorption due to adhered cement paste and mortar.Methods:A new method to produce high quality recycled aggregate by heating and grinding concrete rubbles to separate cement portions adhering to aggregate was developed recently. In this process by-product powder with the fineness of 400m2/kg is generated. By-product recycled fine powder consists of fine particles of hydrated cement and crushed aggregate. To use the recycled fine powder as concrete additives two series of experiments were performed to make clear of the effect of recycled fine powder.Results and Conclusion:Self-compacting concrete with recycled fine powder, granulated blast furnace slag and granulated limestone were tested for slump flow, compressive strength, modulus of elasticity and drying shrinkage. Reduction in super plasticizing effect of high range water reducer was found for concrete with recycled powder. Compressive strength of concrete with recycled fine powder was the same as those with granulated limestone, and lower than those with granulated blast furnace slag. Concrete with recycled fine powder showed lower elastic modulus and higher drying shrinkage than those with granulated blast furnace slag and granulated limestone. The recycled fine powder is usable for self-compacting concrete without further processing, despite the possible increase in dosage of high range water reducer for a given slump flow and in drying shrinkage. The addition of granulated blast furnace slag together with recycled powder to self-compacting concrete improved super plasticizing effect of high range water reducer and properties of concrete.


2020 ◽  
Vol 10 (13) ◽  
pp. 4441 ◽  
Author(s):  
Anna M. Grabiec ◽  
Daniel Zawal ◽  
Waheed Adewale Rasaq

The paper presents the influence of different curing conditions—wet, dry, and protection against water evaporation (PEV)—on selected properties of concretes with different amounts of recycled concrete aggregate (RCA) previously subjected to atmospheric CO2 sequestration. Two types of cement were used, Portland cement and blast-furnace slag cement. The study was performed in laboratory conditions (at the temperature of 20 ± 1 °C and relative humidity of about 60%), according to currently applicable test procedures for most of the measured characteristics of concrete. Additionally, the eco-efficiency indexes (bi and ci) as well as the eco-durability S-CO2 index were calculated. It was found that dry conditions cause the properties of concrete to deteriorate, especially concrete made of blast-furnace slag cement, while PEV allows the achievement of results comparable to wet conditions. Moreover, for series with the highest amounts of coarse recycled aggregate and after longer periods of curing, the difference between the effects of wet curing and protection against water evaporation disappears. The eco-efficiency and eco-durability indexes approach confirms the beneficial effect of blast-furnace slag cement used as a binder, but on the condition of using a proper way of curing.


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