scholarly journals The Effect of Fine and Coarse Recycled Aggregates on Fresh and Mechanical Properties of Self-Compacting Concrete

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1120 ◽  
Author(s):  
Mahmoud Nili ◽  
Hossein Sasanipour ◽  
Farhad Aslani
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Energy Absorption ◽  
Silica Fume ◽  
The Self ◽  
Recycled Aggregates ◽  
Self Compacting Concrete ◽  
Concrete Mixtures ◽  
Natural Aggregates ◽  
Recycled Material

Today, the use of recycled aggregates as a substitute for a part of the natural aggregates in concrete production is increasing. This approach is essential because the resources for natural aggregates are decreasing in the world. In the present study, the effects of recycled concrete aggregates as a partial replacement for fine (by 50%) and coarse aggregates (by 100%) were examined in the self-compacting concrete mixtures which contain air-entraining agents and silica fumes. Two series of self-compacting concrete mixes have been prepared. In the first series, fine and coarse recycled mixtures respectively with 50% and 100% replacement with air entraining agent were used. In the second series, fine recycled (with 50% replacement) and coarse recycled (with 100% replacement) were used with silica fume. The rheological properties of the self-compacting concrete (SCC) were determined using slump-flow and J-ring tests. The tests of compressive strength, tensile strength, and compressive stress-strain behavior were performed on both series. The results indicated that air-entraining agent and silica fume have an important role in stabilization of fresh properties of the mixtures. The results of tests indicated a decrease in compressive strength, modulus of elasticity, and energy absorption of concrete mixtures containing air entrained agent. Also, the results showed that complete replacement (100%) with coarse recycled material had no significant effect on mechanical strength, while replacement with 50% fine recycled material has reduced compressive strength, tensile strength, and energy absorption.

scholarly journals Performance of Recycled Aggregate Concrete for M25 Grade Concrete

2019 ◽  
Vol 9 (2) ◽  
pp. 4694-4700
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Aggregate Concrete ◽  
Inorganic Particles ◽  
Natural Aggregates

Recycled aggregates (RCA) are the aggregates which are made up of crushed, inorganic particles that are obtained from the construction demolition debris. Now a day’s protection of environment is the ultimate challenge to the society. So the usage of RCA’s is the best alternative for the aggregates which are obtained naturally in the construction activity. The scope of using these recycled concrete aggregates is increasing day by day. It reduces the cost effectively as we are using waste concrete as recycled aggregates. The main focus of this paper is to use find the strength qualities of recycled aggregates so as to use it as an alternative for the natural aggregates in high strength concrete for various construction activities. Comparison of workability, compressive strength, tensile strength, elastic modulus and flexural strength of recycled aggregate concrete is made with natural aggregate concrete. Here M25 grade concrete is taken and the natural aggregates were replaced with recycled aggregates in various percentages of 0%, 25%, 50%, 75% and 100%. The mix design for these replacement ratios are done by using code of IS 10262-2009. In order to determine the properties which were mentioned above a total of 60 cubes, 10 beams and 40 cylinders were casted. The compressive strength and tensile strength of RCA concrete have been determined for 7 days and 28 days where as the modulus of elasticity and the flexural strength of RCA concrete are determined after curing for the period of 28 days. The tests done on RCA concrete are compared with concrete which is obtained by natural aggregates As per IS codification the parameters which were determined are reducing moderately as the amount of aggregates which are recycled is being raised

The Influence of Fiber Reinforcement on the Properties of the Self-Compacting Concrete Mix and Concrete

2020 ◽  
Vol 299 ◽  
pp. 112-117
Author(s):  
Margarita A. Goncharova ◽  
Vladimir V. Krokhotin ◽  
Alexander N. Ivashkin
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Fiber Reinforcement ◽  
The Self ◽  
Rheological Characteristics ◽  
Self Compacting Concrete ◽  
Stress Strain ◽  
Concrete Mix ◽  
Technological Effectiveness

The paper considers the influence of fiberglass on the rheological and stress-strain properties of self-compacting concretes. The use of fiberglass in self-compacting concrete compositions makes it possible to achieve a sufficient coefficient of grain separation in coarse and fine fillers, which significantly influences the mobility and technological effectiveness of self-compacting mixes. Optimum compositions of self-compacting concretes are obtained, rational volumes of the hyper-plasticizing additive and of fiberglass are determined. The components were selected experimentally, in order to optimize the composition according to rheological characteristics. It is established that the use of fiberglass positively influences the stress-strain characteristics of concrete: it raises the compressive strength, as well as the bending tensile strength without deteriorating the workability and spreadabilityof the self-compacting concrete mix.

scholarly journals Natural aggregate totally replacement by mechanically treated concrete waste

2015 ◽  
Vol 10 (1) ◽  
pp. 83-90
Author(s):  
Jozef Junak ◽  
Nadezda Stevulova
Keyword(s):  
Compressive Strength ◽  
Concrete Strength ◽  
Reference Sample ◽  
Average Density ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Natural Aggregates ◽  
Recycled Material

Abstract This paper presents the results obtained from the research focused on the utilization of crushed concrete waste aggregates as a partial or full replacement of 4/8 and 8/16 mm natural aggregates fraction in concrete strength class C 16/20. Main concrete characteristics such as workability, density and compressive strength were studied. Compressive strength testing intervals for samples with recycled concrete aggregates were 2, 7, 14 and 28 days. The amount of water in the mixtures was indicative. For mixture resulting consistency required slump grade S3 was followed. Average density of all samples is in the range of 2250 kg/m3 to 2350 kg/m3. The highest compressive strength after 28 days of curing, 34.68 MPa, reached sample, which contained 100% of recycled material in 4/8 mm fraction and 60% of recycled aggregates in 8/16 mm fraction. This achieved value was only slightly different from the compressive strength 34.41 MPa of the reference sample.

Effects of different size of fly ash as cement replacement on self-compacting concrete properties

2019 ◽  
Vol 1 (2) ◽  
pp. 180-186
Author(s):  
Dilan Rantung ◽  
Steve W.M. Supit ◽  
Seska Nicolaas
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Building Construction ◽  
Particle Sizes ◽  
Self Compacting Concrete ◽  
Cement Replacement ◽  
Concrete Mixtures ◽  
Water Curing ◽  
Passing Ability

This paper aims to investigate experimentally the influence of replacing cement with different fineness of fly ash based on flowability, passing ability, compressive strength, tensile strength (splitting). Concretes with 15% fly ash (passed a number 100 sieve) and fine fly ash (passed a number 200 sieve) as cement replacement were cast and tested at 7, 14, 28 days after water curing. A superplasticizer in the form of viscocrete 3115 N was constantly used for each concrete mixtures as much as 1% by weight of cement. The results show that the use of fly ash does not significantly increased the compressive strength and tensile strength of SCC mixtures. However, concrete with 15% fine fly ash its self and combined 7.5% fly ash with 7.5% fine fly ash show better flowability and passing ability when compared to concrete with cement only indicating the performance of using smaller particle sizes of fly ash could lead better properties of SCC that can be potentially used for building construction application.

scholarly journals Resistance of Recycled Aggregate Concrete (RAC) Subjected to Drying-Wetting Cycles to Attack of Magnesium and Sodium Sulfates

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Esam Hewayde ◽  
Alireza Pachenari ◽  
Hussin Al-Eleaj
Keyword(s):  
Compressive Strength ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Partial Immersion ◽  
Concrete Mixtures ◽  
Sulfate Solutions ◽  
Mass Losses ◽  
Natural Aggregates ◽  
Sodium Sulfates

Recycled aggregates were widely used in the concrete industry as a replacement of natural aggregates in the last two decades. In this study, the resistance of concrete mixtures having various levels of recycled aggregate as a replacement of natural coarse aggregate to the attack of magnesium and sodium sulfates was investigated. Five mixtures made with 0%, 25%, 50%, 75%, and 100% recycled aggregate were partially immersed in magnesium and sodium sulfate solutions having concentrations of 2.5%, 4.5%, and 6.5% and subjected to drying-wetting cycles for a total of 10 weeks. Mass losses of concrete specimens owing to the attack of sulfate solutions and the effect of drying-wetting cycles were recorded weekly. Results show that the incorporation of recycled aggregate decreased the compressive strength of concrete at ages of 7 and 28 days. The decline in the compressive strength was more significant when the replacement percentage exceeds 50%. Mass losses of concrete specimens were found to be increased as the level of recycled aggregate increased. Mass losses of concrete specimens having 100% recycled aggregate were approximately as twice as those of concrete specimens having 0% recycled aggregate owing to 10 weeks of partial immersion in magnesium sulfate solutions of concentrations of 2.5%, 4.5%, and 6.5%. The attack of sodium sulfates was less aggressive than that of the magnesium sulfates. Results also show that the reduction in the compressive strength is directly proportional to the mass loss following a linear equation of R-squared value of 0.937.

scholarly journals Impact Energy Consumption of High-Volume Rubber Concrete with Silica Fume

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Hai-long Li ◽  
Ying Xu ◽  
Pei-yuan Chen ◽  
Jin-jin Ge ◽  
Fan Wu
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Energy Absorption ◽  
Silica Fume ◽  
Impact Energy ◽  
Impact Resistance ◽  
Absorption Capacity ◽  
Rubberized Concrete ◽  
Energy Absorption Capacity ◽  
Fine Aggregates

Adding rubber to concrete aims to solve the environmental pollution problem caused by waste rubber and to improve the energy absorption and impact resistance of concrete. In this paper, recycled rubber particles were used to replace fine aggregates in Portland cement concrete to combine the elasticity of rubber with the compression resistance of concrete. Fine aggregates in the concrete mixes were partially replaced with 0%, 20%, 40%, and 60% rubber by volume, and the cement in the concrete mixes was replaced with 0%, 5%, and 10% of silica fume by mass. The properties of the concrete specimens were examined through compressive strength, splitting tensile strength, flexural loading, and rebound tests. Results show that the compressive strength of concrete and the splitting tensile strength decreased to 11.81 and 1.31 MPa after adding silica fume to enhance the strength 37.8% and 23.7%, respectively, and the dosage of rubber was 60%. With the addition of rubber, the impact energy of rubberized concrete was 2.39 times higher than that of ordinary concrete, while its energy absorption capacity was 9.46% higher. The addition of silica fume increased its impact energy by 3.06 times, but the energy absorption capacity did not change significantly. In summary, the RC60SF10 can be used on non-load-bearing structures with high impact resistance requirements. A scanning electron microscope was used to examine and analyze the microstructural properties of rubberized concrete.

scholarly journals Effect of steel fibers over the Self Compacting Concrete

2019 ◽  
Vol 9 (2S2) ◽  
pp. 38-41 ◽  
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Construction Industry ◽  
Steel Fibers ◽  
The Self ◽  
Engineering Properties ◽  
Self Compacting Concrete ◽  
Split Tensile Strength ◽  
Conventional Concrete ◽  
Good Outcome

The introduction of self-compacting concrete in the construction industry overcomes the flaws caused due to the improper compaction of concrete. Fibers are proved to increase the properties of conventional concrete. This research focuses on the performance of self-compacting concrete after augmenting steel fibers. The steel fibers are added in proportions such as 0.25 percentage, 0.5 percentage, 0.75 percentage and 1 percentage. After casting the self- compacting concrete, the strength was assessed for 7 days and 28 days and its compressive strength and split tensile strength was analyzed. The inclusion of steel fibers yielded good outcome in the tests and it is proved to yield better engineering properties.

scholarly journals Effect of Recycled Coarse Aggregates in Properties of Concrete

2008 ◽  
Vol 3 (4) ◽  
pp. 130-137 ◽  
Author(s):  
R Kumutha ◽  
K Vijai
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Modulus Of Elasticity ◽  
Coarse Aggregate ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Split Tensile Strength ◽  
Coarse Aggregates ◽  
The Cost

The properties of concrete containing coarse recycled aggregates were investigated. Laboratory trials were conducted to investigate the possibility of using recycled aggregates from the demolition wastes available locally as the replacement of natural coarse aggregates in concrete. A series of tests were carried out to determine the density, compressive strength, split tensile strength, flexural strength and modulus of elasticity of concrete with and without recycled aggregates. The water cement ratio was kept constant for all the mixes. The coarse aggregate in concrete was replaced with 0%, 20%, 40%, 60%, 80% and 100% recycled coarse aggregates. The test results indicated that the replacement of natural coarse aggregates by recycled aggregates up to 40% had little effect on the compressive strength, but higher levels of replacement reduced the compressive strength. A replacement level of 100% causes a reduction of 28% in compressive strength, 36% in split tensile strength and 50% in flexural strength. For strength characteristics, the results showed a gradual decrease in compressive strength, split tensile strength, flexural strength and modulus of elasticity as the percentage of recycled aggregate used in the specimens increased. 100% replacement of natural coarse aggregate by recycled aggregate resulted in 43% savings in the cost of coarse aggregates and 9% savings in the cost of concrete.

Flexural behaviour of hybrid fibre (steel fiber and silica fume) reinforced self compacting composite concrete members

2014 ◽  
Vol 11 (4) ◽  
pp. 323-330 ◽  
Author(s):  
S. Arivalagan
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
Steel Fiber ◽  
Volume Fraction ◽  
Hardened Concrete ◽  
Flexural Behaviour ◽  
Self Compacting Concrete ◽  
Engineering Structures ◽  
Conventional Concrete ◽  
Concrete Members

The present day world is witnessing the construction of very challenging and difficult civil engineering structures. Self-compacting concrete (SCC) offers several economic and technical benefits; the use of steel fiber extends its possibilities. Steel fiber acts as a bridge to retard their cracks propagation, and improve several characteristics and properties of the concrete. Therefore, an attempt has been made in this investigation to study the Flexural Behaviour of Steel Fiber Reinforced self compacting concrete incorporating silica fume in the structural elements. The self compacting concrete mixtures have a coarse aggregate replacement of 25% and 35% by weight of silica fume. Totally eight mixers are investigated in which cement content, water content, dosage of superplasticers were all constant. Slump flow time and diameter, J-Ring, V-funnel, and L-Box were performed to assess the fresh properties of the concrete. The variable in this study was percentage of volume fraction (1.0, 1.5) of steel fiber. Finally, five beams were to be casted for study, out of which one was made with conventional concrete, one with SCC (25% silica fume) and other were with SCC (25% silica fume + 1% of steel fiber, 25% silica fume + 1.5% of steel fiber) one with SCC (35% silica fume), and other were SCC (35% Silica fume + 1% of steel fiber, 35% Silica fume + 1.5% of steel fiber). Compressive strength, flexural strength of the concrete was determined for hardened concrete for 7 and 28 days. This investigation is also done to determine the increase the compressive strength by addition of silica fume by varying the percentage.

scholarly journals Mechanical Effect of Steel Fiber on the Cement Replacement Materials of Self-Compacting Concrete

Fibers ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 36 ◽  
Author(s):  
Hisham Alabduljabbar ◽  
Rayed Alyousef ◽  
Fahed Alrshoudi ◽  
Abdulaziz Alaskar ◽  
Ahmed Fathi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Silica Fume ◽  
Steel Fiber ◽  
Mechanical Effect ◽  
Splitting Tensile Strength ◽  
Self Compacting Concrete ◽  
Cement Replacement ◽  
Filling Ability ◽  
Concrete Mix

The behaviors of the fresh and mechanical properties of self-compacting concrete (SCC) are different from those of normal concrete mix. Previous research has investigated the benefits of this concrete mix by incorporating different constituent materials. The current research aims to develop a steel fiber reinforcement (SFR)‒SCC mixture and to study the effectiveness of different cement replacement materials (CRMs) on the fresh and mechanical properties of the SFR‒SCC mixtures. CRMs have been used to replace cement content, and the use of different water/cement ratios may lower the cost of CRMs, which include microwave-incinerated rice husk ash, silica fume, and fly ash. Fresh behavior, such as flow and filling ability and capacity segregation, was examined by a special test in SCC on the basis of their specifications. Moreover, compressive and splitting tensile strength tests were determined to simulate the hardened behavior for the concrete specimens. Experimental findings showed that, the V-funnel and L-box were within the accepted range for SCC. Tensile and flexural strength increases upon the use of 10% silica fume were found when compared with other groups; the ideal percentage of steel fiber that should be combined in this hybrid was 2% of the total weight of the binder. Overall, steel fibers generated a heightened compressive and splitting tensile strength in the self-compacting concrete mixes.

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