Experimental Study on the Fundamental Characteristics of Different Parent Recycled Concrete Fine Aggregates

2013 ◽  
Vol 368-370 ◽  
pp. 1080-1085 ◽  
Author(s):  
Yong Jun Qin ◽  
Lei Li ◽  
Aihemaiti Yibulayin ◽  
Guang Tai Zhang ◽  
Rui Liang
Keyword(s):  
Concrete Strength ◽  
High Strength ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Fine Aggregate ◽  
Strength Concrete ◽  
Recycled Fine Aggregate ◽  
Fine Aggregates ◽  
Different Types ◽  
Overall Performance

Recycled aggregate performance vary with different native concrete strength and use environment. Recycled fine aggregate was obtained after the primary concrete was broken and screened. According to Recycled coarse aggregate for concrete and mortar (GB/T 25176-2010), the physical properties of the different types of recycled fine aggregate were analyzed, in addition, determine the classification. The results shows that the properties of recycled fine aggregate all meet the level and they are vary by strengths of its maternal primary concrete and using environments. The overall performance of fine aggregate of high strength primary concrete is the best, followed by the low strength concrete and the moderate strength concrete.

The Study on the Impact of Recycled Fine Aggregate and Powder on the Mechanics and Thermal Performance of Recycled Concrete Hollow Blocks

2012 ◽  
Vol 509 ◽  
pp. 119-122
Author(s):  
Wei Zhou ◽  
Ling Huan Lu ◽  
Zhen Li
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Thermal Performance ◽  
High Strength ◽  
Recycled Concrete ◽  
Fine Aggregate ◽  
Ordinary Concrete ◽  
Recycled Fine Aggregate ◽  
The Impact ◽  
The Heat Transfer Coefficient

The impact of recycled fine aggregate and powder on the mechanics and thermal performance of recycled concrete hollow blocks was discussed in this paper. The results showed that 30% recycled fine aggregate and powder have slight affect on the strength of recycled concrete hollow blocks. But the strength reduced significantly when the replacement is above 50%. The impact of recycled fine aggregate and powder on the performance of concrete hollow blocks with high strength grade is notable . The heat transfer coefficient of recycled concrete hollow blocks with 30% recycled fine aggregate and powder was equivalently to ordinary concrete hollow blocks.

scholarly journals Durability and Shrinkage Characteristics of Self-Compacting Concretes Containing Recycled Coarse and/or Fine Aggregates

2015 ◽  
Vol 2015 ◽  
pp. 1-18 ◽  
Author(s):  
Mehmet Gesoglu ◽  
Erhan Güneyisi ◽  
Hatice Öznur Öz ◽  
Mehmet Taner Yasemin ◽  
Ihsan Taha
Keyword(s):  
Coarse Aggregate ◽  
Gas Permeability ◽  
Drying Shrinkage ◽  
Recycled Aggregate ◽  
Fine Aggregate ◽  
Restrained Shrinkage ◽  
Durability Properties ◽  
Recycled Fine Aggregate ◽  
Restrained Shrinkage Cracking ◽  
Fine Aggregates

This paper addresses durability and shrinkage performance of the self-compacting concretes (SCCs) in which natural coarse aggregate (NCA) and/or natural fine aggregate (NFA) were replaced by recycled coarse aggregate (RCA) and/or recycled fine aggregate (RFA), respectively. A total of 16 SCCs were produced and classified into four series, each of which included four mixes designed with two water to binder (w/b) ratios of 0.3 and 0.43 and two silica fume replacement levels of 0 and 10%. Durability properties of SCCs were tested for rapid chloride penetration, water sorptivity, gas permeability, and water permeability at 56 days. Also, drying shrinkage accompanied by the water loss and restrained shrinkage of SCCs were monitored over 56 days of drying period. Test results revealed that incorporating recycled coarse and/or fine aggregates aggravated the durability properties of SCCs tested in this study. The drying shrinkage and restrained shrinkage cracking of recycled aggregate (RA) concretes had significantly poorer performance than natural aggregate (NA) concretes. The time of cracking greatly prolonged as the RAs were used along with the increase in water/binder ratio.

Influence of Recycled Aggregate on the Rheological Behavior of Cement Mortar

2014 ◽  
Vol 600 ◽  
pp. 297-307 ◽  
Author(s):  
Paulo Roberto Lopes Lima ◽  
Romildo Dias Toledo Filho ◽  
Otávio da Fonseca Martins Gomes
Keyword(s):  
Yield Stress ◽  
Plastic Viscosity ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Fine Aggregate ◽  
Demolition Waste ◽  
Cement Ratio ◽  
Recycled Fine Aggregate ◽  
Fine Aggregates ◽  
Physical Tests

In this work it was studied the influence of recycled fine aggregate obtained from construction and demolition waste (CDW) on the rheological properties of Portland cement mortars. The CDW was initially separate in their main constituents (mortar, ceramic and concrete debris) at the laboratory and then grinded separately to the sand size in order to generate more homogeneous fine aggregates. The characterization of the natural and recycled sands was carried out through physical tests, X-ray diffraction, scanning electron microscopy (SEM), and image analysis (shape and texture description parameters). A conventional mortar and three mortars containing recycled sands were produced with a sand/cement ratio of 4 and consistency index of 255±5 mm. The consistency was kept constant by ranging the water-cement ratio from 0.58 to 1.14. The rheological study was performed using a rotating viscometer to obtain torque-rotation ratio and to calculate the yield stress and plastic viscosity. The results indicate that the presence of recycled aggregate causes a lowering of both yield stress and plastic viscosity with respect to the mortar containing natural aggregate.

scholarly journals Bond Behavior Between Recycled Concrete Containing CDW and Different Types of Steel Bars

2021 ◽  
Vol 4 (2) ◽  
Author(s):  
Carine N. S. Reis ◽  
Paulo R. L. Lima ◽  
Mônica B. Leite
Keyword(s):  
Recycled Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Fine Aggregate ◽  
Demolition Waste ◽  
Conventional Concrete ◽  
Recycled Fine Aggregate ◽  
Steel Bar ◽  
Internal Forces ◽  
Steel Rebars

The operation of reinforced concrete structures is directly associated with the adhesion between the steel bar and the concrete, which allows the internal forces to be transferred to the reinforcement during the process of loading the structural elements. The modification of the concrete composition, with the introduction of recycled aggregate from construction and demolition waste (CDW), affects the steel-concrete interface and can modify the bonding stress, which is also influenced by the type and diameter of the bar used. In this work, the influence of the recycled fine aggregate (RFA) and types of steel bar on the steel-concrete bond was experimentally evaluated using the pullout test. Conventional concrete and recycled concrete, with RFA replacement level of 25%, were produced. Two types of steel rebars (i.e.,plain and deformed) with  diameters of 10.0 and 16.0mm were considered in this paper. The results indicate a reduction in the adhesion stress with the introduction of recycled aggregate, but this trend is influenced by the diameter of the bar used. The use of ribbed bars modifies the stress bon-slip behavior, with an increase in the average bond strength, which is also observed with the reduction of the diameter of the bar.

MECHANICAL PROPERTIES AND SHRINKAGE PROPERTIES OF THE CONCRETE WITH RECYCLED FINE AGGREGATE AND ADMIXTURE

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Yuji Nakata ◽  
Koji Takasu ◽  
Hidehiro Koyamada ◽  
Hiroki Suyama
Keyword(s):  
Compressive Strength ◽  
Pore Volume ◽  
Drying Shrinkage ◽  
High Strength ◽  
Recycled Aggregate ◽  
Fine Aggregate ◽  
Shrinkage Ratio ◽  
Recycled Fine Aggregate ◽  
High Durability ◽  
The Relationship

In Japan, it is forecasted that massive amounts of concrete waste material will be generated in the future as a result of demolition of many buildings, and expansion of the use of recycled aggregate is expected. In this study, it was verified the effect when relatively large amount of admixture is mixed, a combination of recycled fine aggregate of different quality and various admixtures, combination of each admixture in order to realize high strength and high durability by using recycled aggregate. The increase in the drying shrinkage ratio due to the deterioration of the recycled fine aggregate quality was larger than the fluctuation due to the admixture mixing ratio and the drying shrinkage ratio was distributed by forming a group for each quality of recycled fine aggregate. In the relationship between the pore volume and the compressive strength, when evaluated with pore volume of 2 μm or less in both cases, a good linear relationship could be confirmed. The relationship between the pore volume and the drying shrinkage rate was similar. Therefore, it was suggested that compressive strength and drying shrinkage ratio of mortar contained composite recycled fine aggregate and admixture could be predicted by evaluating with the pore volume of 2 μm or less.

Microstructural Features of Recycled Aggregate Concrete: From Non-Structural to High-Performance Concrete

2019 ◽  
Vol 25 (3) ◽  
pp. 601-616 ◽  
Author(s):  
Diogo Pedro ◽  
Mafalda Guedes ◽  
Jorge de Brito ◽  
Luís Evangelista
Keyword(s):  
High Performance ◽  
Mechanical Performance ◽  
High Performance Concrete ◽  
Concrete Strength ◽  
High Strength ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Sequential Approach

AbstractThe use of concrete-recycled aggregates to produce high-performance concrete is limited by insufficient correlation between resulting microstructure and its influence on mechanical performance reproducibility. This work addresses this issue in a sequential approach: concrete microstructure was systematically analyzed and characterized by scanning electron microscopy and results were correlated with concrete compressive strength and water absorption ability. The influence of replacing natural aggregates (NA) with recycled concrete aggregates (RCA), with different source concrete strength levels, of silica fume (SF) addition and of mixing procedure was tested. The results show that the developed microstructure depends on the concrete composition and is conditioned by the distinct nature of NA, recycled aggregates from high-strength source concrete, and recycled aggregates from low-strength source concrete. SF was only effective at concrete densification when a two-stage mixing approach was used. The highest achieved strength in concrete with 100% incorporation of RCA was 97.3 MPa, comparable to that of conventional high-strength concrete with NA. This shows that incorporation of significant amounts of RCA replacing NA in concrete is not only a realistic approach to current environmental goals, but also a viable route for the production of high-performance concrete.

scholarly journals ANÁLISE DAS PROPRIEDADES DO CONCRETO UTILIZANDO RESÍDUOS DA CONSTRUÇÃO CIVIL

2018 ◽  
Vol 10 (Especial) ◽  
pp. 60-64
Author(s):  
Leandro Miranda dos Santos ◽  
Larissa Queiroz Minillo ◽  
Daniele Araujo Altran ◽  
Filipe Bittencourt Figueiredo
Keyword(s):  
Concrete Strength ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Fine Aggregate ◽  
Low Resistance ◽  
Average Resistance ◽  
Cure Time

The impacts caused by RCCs are growing exponentially each year, which is why it is necessary to create measures to mitigate and minimize such an effect. The purpose of this research was to evaluate the physicalmechanical properties of the concrete from the gradual replacement of the natural fine aggregate by the recycled aggregate. The recycled concrete was made with substitutions of 20, 40, 60, 80 and 100% of recycled aggregate, whose water / cement factor was 0.7. Test specimens were produced and after the cure time of 7, 14 and 28 days the specimens were ruptured. It was possible to analyze that with the increase of the recycled aggregate substitution, the concrete strength increased, but did not reach an average resistance of 20 Mpa. Therefore it is possible to conclude that the use of recycled aggregate in the manufacture of low resistance concrete is.

scholarly journals Mechanical Properties of Recycled Aggregate Self-Compacting High Strength Concrete Utilizing Waste Fly Ash, Cellular Concrete and Perlite Powders

2019 ◽  
Author(s):  
Mohammed Abed ◽  
Rita Nemes
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
High Strength Concrete ◽  
High Strength ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Partial Replacement ◽  
Powder Materials ◽  
Strength Concrete ◽  
Cellular Concrete

The sustainability of engineering products has become a basic requirement instead of a mere choice because the harmony between economic activity and the earth’s ecosystem must be seriously considered. The influence of using three unprocessed waste powder materials as cement replacing materials (CRMs) and/or coarse recycled concrete aggregate (RCA) as a partial replacement of coarse natural aggregate (NA) on fresh and mechanical properties of self-compacting high-strength concrete (SCHSC) is investigated in this study. The activation index of the CRMs on the cement paste is tested as an initial step. The CRMs, namely, waste fly ash (WFA), waste perlite powder (WPP) and waste cellular concrete (WCC), are tested through 21 mixtures allocated by seven different series with three mixes of each. The mechanical properties of the 21 concrete mixes are determined after one, three and nine months of curing. Results of compressive strength, splitting tensile strength, flexural strength and modulus of elasticity are presented. This work shows that the mechanical and environmental performance of SCHSC can be improved by the replacement of NA by RCA of up to 50% and the replacement of cement by WPP or WFA of up to 15%. Using WCC is not recommended to be reached 15% and using WFA is preferable to be with incorporating RCA rather than NA alone. Findings indicate that incorporating waste materials can be valuable in SCHSC, thereby potentially leading to an increasingly green environment and paving the way for advancements in sustainable construction.

Experimental Investigation for the Influence of Recycled Aggregate Replacement Content on Tension-Compression Strength

2015 ◽  
Vol 744-746 ◽  
pp. 1412-1415 ◽  
Author(s):  
Zong Ming Jia ◽  
Qing Han ◽  
Ming Hao Liu
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Splitting Tensile Strength ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Fine Aggregate ◽  
Recycled Fine Aggregate ◽  
Strength Formula

Designing recycled concrete mixture proportion of different recycled coarse and fine aggregate replacement content by pulp content ,then testing compressive strength and splitting tensile strength. The text results show that: With the increasing of recycled aggregate content , the compressive strength and splitting tensile strength of recycled aggregate concrete trended to decrease. Compared to recycled coarse aggregate, recycled fine aggregate impact on the properties of recycled concrete is greater. Establishing the compressive strength and splitting tensile strength formula of recycled concrete based on a lot of experimental results.

scholarly journals Prediction of Corner Columns’ Load Capacity Using Composite Material Analogy

2018 ◽  
Vol 8 (2) ◽  
pp. 2745-2749
Author(s):  
A. Ali ◽  
Z. Soomro ◽  
S. Iqbal ◽  
N. Bhatti ◽  
A. F. Abro
Keyword(s):  
Composite Material ◽  
Load Capacity ◽  
Construction Material ◽  
Concrete Strength ◽  
Axial Loading ◽  
High Strength ◽  
Strength Concrete ◽  
Different Types ◽  
Normal Strength ◽  
The One

There are numerous reasons for which concrete has become the most widely used construction material in buildings, one of them being its availability in different types, such as fiber-reinforced, lightweight, high strength, conventional and self-compacting concrete. This advantage is specially realized in high-rise building construction, where common construction practice is to use concretes of different types or strength classes in slabs and columns. Columns in such structures are generally made from concrete which is higher in compressive strength than the one used in floors or slabs. This raises issue of selection of concrete strength that should be used for estimating column capacity. Current paper tries to address this issue by testing nine (09) sandwich column specimens under axial loading. The floor concrete portion of the sandwich column was made of normal strength concrete, whereas column portions from comparatively higher strength concrete. Test results show that aspect ratio (h/b) influences the effective concrete strength of such columns. A previously adopted methodology of composite material analogy with some modifications has been found to predict well the capacity of columns where variation in floor and concrete strength is significant.

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