scholarly journals Experimental Study of Utilizing Recycled Fine Aggregate for the Preparation of High Ductility Cementitious Composites

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 679
Author(s):  
Dan Ying Gao ◽  
Mingyan Lv ◽  
Lin Yang ◽  
Jiyu Tang ◽  
Gang Chen ◽  
...  
Keyword(s):  
Prediction Models ◽  
Volume Fraction ◽  
Fine Aggregate ◽  
Peak Strain ◽  
High Ductility ◽  
Test Results ◽  
Cementitious Composite ◽  
Fiber Volume ◽  
Recycled Fine Aggregate ◽  
Good Agreement

Waste concrete was recycled and crushed into fine aggregate to prepare a high ductility cementitious composite (HDCC) in this study, for helping dispose the massive amount of construction waste and for reserving natural resources. Firstly, the features of recycled fine aggregate (RFA) were analyzed in detail and compared with natural fine aggregate (NFA). After that, the mechanical properties, including compression, flexure, bending and tension, and the microstructure of high ductility cementitious composite (HDCC) prepared with RFA were systematically investigated and compared with that of HDCC prepared with NFA. The results show that, since RFA has a higher water absorption rate and contains 4.86 times as much crush dust as NFA, HDCC with RFA forms a denser matrix and a higher bond between fiber and matrix than HDCC with NFA. Thus, HDCC with RFA has higher compressive, flexural, bending and tensile strength. Meanwhile, the higher bond between the fiber and matrix of HDCC with RFA and the finer particle sizes of RFA can greatly promote the development of multiple cracking. As a result, HDCC with RFA exhibits more remarkable stain hardening, and presents 182.73% higher peak deflection in bending and 183.33% higher peak strain in tension than HDCC with NFA. Finally, with the consideration of fiber volume fraction, the prediction models for the peak strengths of HDCC with RFA were proposed. The prediction results show a good agreement with the test results.

scholarly journals Effect of Fiber Content on the Mechanical Properties of Engineered Cementitious Composites with Recycled Fine Aggregate from Clay Brick

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3272
Author(s):  
Zhanqi Cheng ◽  
Wenhao Yan ◽  
Zhibo Sui ◽  
Jiyu Tang ◽  
Chengfang Yuan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Size Effect ◽  
Quartz Sand ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Cementitious Composites ◽  
Fine Aggregate ◽  
Fiber Volume ◽  
Engineered Cementitious Composites ◽  
Recycled Fine Aggregate

In this study, recycled fine aggregate (RFA), also known as recycled brick micro-powder (RBM), was used to completely replace quartz sand for the preparation of green, low-cost ecological engineered cementitious composites (ECO-ECC). RFA was used to replace ultrafine silica sand in the range of 0–100%. Firstly, the optimal replacement rate of RFA was determined, and the test results showed that the ECO-ECC prepared by fully replacing quartz sand with RFA as fine aggregate had strain hardening and multiple cracks, and the tensile strain of the specimens could reach 3%. Then the effects of fiber volume fraction and size effect on the mechanical properties of ECO-ECC were systematically investigated. The results showed that the fiber volume fraction has some influence on the mechanical properties of ECO-ECC. With the increase of fiber volume fraction, the ultimate deflection of the material keeps increasing up to 44.87 mm and the ultimate strain up to 3.46%, with good ductility and toughness. In addition, the compressive strength of the material has a good size effect, and there is a good linear relationship between different specimen sizes and standard sizes. It provides a good basis for engineering applications. Microscopic experimental results also showed that fibers play an important bridging role in the material, and the fiber pull-out and pull-break damage effects are significant.

scholarly journals Influence of polyvinyl alcohol fiber and fly ash content on compressive creep properties of high ductility cementitious composites

2021 ◽  
Vol 272 ◽  
pp. 02014
Author(s):  
Bo Chen ◽  
Liping Guo ◽  
Lihui Zhang ◽  
Wenxiao Zhang ◽  
Yin Bai ◽  
...  
Keyword(s):  
Fly Ash ◽  
Polyvinyl Alcohol ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Ash Content ◽  
Creep Model ◽  
High Ductility ◽  
Fiber Volume ◽  
Leading Role ◽  
Pva Fiber

The influence of polyvinyl alcohol (PVA) fiber volume fraction and fly ash content on the creep behavior of high ductility cementitious composites (HDCC) under compression was investigated. For this investigation, the creep behavior of four HDCC groups with cube compressive strength of 30–50 MPa, PVA fiber volume fraction of 1.5% and 2.0%, and fly ash content of 60% and 80% at 7 d and 28 d loading periods, respectively, were evaluated. A compressive creep model, which reflects the loading age and holding time, was established. The results revealed that when the load was applied at 7 d and 28 d, and then maintained for 245 d, the specific creep of HDCC ranged from 95×10-6/ MPa to 165×10-6/ MPa and from 59×10-6/ MPa to 135 × 10−6/ MPa, respectively. The corresponding creep coefficients ranged from 1.48 to 2.25 and from 1.10 to 1.94, respectively. The PVA fiber volume fraction and fly ash content were the main factors affecting the specific creep of HDCC, which increased with increasing fiber fraction and fly ash content. Under short-term loading, the fiber volume fraction played a leading role in the specific creep, and the fly ash content played the leading role during long-term loading. Furthermore, the specific creep and creep coefficient decreased significantly with increasing loading age. The classical creep model described by a power exponent function is suitable for HDCC.

scholarly journals Investigation on the Mechanical Properties of Fiber Reinforced Recycled Concrete

2016 ◽  
Vol 2 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Hasan Jalilifar ◽  
Fatholla Sajedi ◽  
Sadegh Kazemi
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Experimental Test ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Fiber Content ◽  
Recycled Concrete ◽  
Test Results ◽  
Fiber Volume ◽  
Flexural Toughness

The flexural strength of conventional concrete material is known to be enhanced by incorporating a moderate volume-fraction of randomly distributed fibers. However, there is limited information on describing the influence of fiber volume-fraction on the compressive and flexural strength of recycled coarse aggregate concrete (RCA-C) material. This paper reports on experimental test results of the RCA-C material replaced with 0, 30, 50 and 100% recycled aggregate and 0, 0.5, 1 and 1.5% steel fiber volume fraction. Three-point flexural tests of notched prism specimens were completed. The mechanical properties in compression were characterized using cube specimens. Significant improvement in compressive and flexural strength of RCA-C was found as fiber content increased from 0 to 1.5%. The experimental test results of RCA-C were further evaluated to investigate the influence of fiber content on flexural toughness. According to test results, the addition of steel fibers to RCA-C material appreciably increased the flexural toughness.

Feasibility Studies on Demolition Recycled Fine Aggregate and Sea Sand as Partial Preplacement to Natural Fine Aggregate in Concrete

2021 ◽  
Vol 7 (3) ◽  
Author(s):  
Kishor Kumar B. R ◽  
Kishor Kumar B. R ◽  
Kishor Kumar B. R ◽  
Kishor Kumar B. R
Keyword(s):  
Research Work ◽  
Feasibility Studies ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Test Results ◽  
Split Tensile Strength ◽  
The Sustainable Development ◽  
Recycled Fine Aggregate ◽  
Mix Proportion ◽  
Sea Sand

In this research work, an attempt is being made to partially replace the natural fine aggregate with sea sand and recycled fine aggregate obtained from demolished concrete waste in varied proportions to concrete mix and subject the specimens to mechanical strength tests for short and long durations of 7, 28, 56 and 90 days curing. The compressive strength, split tensile strength and flexural strength results of 30% mix proportion (15% Sea sand + 15% demolished waste sand) were found to be 58.3 N/mm2, 3.53 N/mm2 and 4.71N/mm2 respectively. All the three strength test results obtained were found to yield 15% higher strength than the control specimens. Finally, it can be concluded that partial replacement of natural fine aggregate by sea sand and demolition recycled fine aggregate in construction industry, not only eliminates the waste management problems and impacts on environment, but also leads to the sustainable development by reducing the consumption of natural resources.

scholarly journals Compressive Behavior Characteristics of High-Performance Slurry-Infiltrated Fiber-Reinforced Cementitious Composites (SIFRCCs) under Uniaxial Compressive Stress

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 159 ◽  
Author(s):  
Seungwon Kim ◽  
Seungyeon Han ◽  
Cheolwoo Park ◽  
Kyong-Ku Yun
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Compressive Stress ◽  
High Performance ◽  
Volume Fraction ◽  
Fiber Reinforced Concrete ◽  
Cementitious Composite ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Behavior Characteristics

The compressive stress of concrete is used as a design variable for reinforced concrete structures in design standards. However, as the performance-based design is being used with increasing varieties and strengths of concrete and reinforcement bars, mechanical properties other than the compressive stress of concrete are sometimes used as major design variables. In particular, the evaluation of the mechanical properties of concrete is crucial when using fiber-reinforced concrete. Studies of high volume fractions in established compressive behavior prediction equations are insufficient compared to studies of conventional fiber-reinforced concrete. Furthermore, existing prediction equations for the mechanical properties of high-performance fiber-reinforced cementitious composite and high-strength concrete have limitations in terms of the strength and characteristics of contained fibers (diameter, length, volume fraction) even though the stress-strain relationship is determined by these factors. Therefore, this study developed a high-performance slurry-infiltrated fiber-reinforced cementitious composite that could prevent the fiber ball phenomenon, a disadvantage of conventional fiber-reinforced concrete, and maximize the fiber volume fraction. Then, the behavior characteristics under compressive stress were analyzed for fiber volume fractions of 4%, 5%, and 6%.

scholarly journals Tensile Strength and Density Evaluation of Composites from Waste Cotton Fabrics and High-Density Polyethylene (HDPE): Contributions to the Composite Industry and a Cleaner Environment

2021 ◽  
Vol 1 (1) ◽  
pp. 41-47
Author(s):  
Sri Mulyo Bondan Respati ◽  
Helmy Purwanto ◽  
Ilham Fakhrudin ◽  
Pungkas Prayitno
Keyword(s):  
Tensile Strength ◽  
Textile Industry ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Cotton Fabrics ◽  
Test Results ◽  
Fiber Volume ◽  
Waste Cotton Fabrics ◽  
Density Evaluation ◽  
Straight Fiber

The growth of the textile industry and the massive use of plastic-based materials create economic growth, but it produces waste from post-use, such as clothing waste from cotton fabrics and HDPE that can be recycled and combined as composite materials. Therefore, an experiment was carried out to investigate and analyze the effect of the fiber volume fraction of waste cotton fabric (1.5%, 3.5%, 4.5%, 6%, and 7.5%) with straight fiber arrangement on the tensile strength and density. From the test results, a tensile strength of 178.4 MPa and 182.6 MPa was obtained for yield and max stress, respectively at a fiber volume fraction of 7.5%. Meanwhile, the highest density of 0.95 g/cm3 was obtained at 1.5% fiber volume fraction. The fracture macroscopic view of the specimen shows a resilience fracture (uneven and appears stringy). Although the strength of this composite cannot yet compete with the new composite material, it has a decent environmental contribution. Considering the availability of waste cotton fabrics and HDPE, it promises to be produced as a low-strength composite for construction, ornamentation, or coatings.

scholarly journals ANALISA KEKUATAN BENDING KOMPOSIT EPOXY DENGAN PENGUATAN SERAT NILON

2011 ◽  
Vol 1 (1) ◽  
Author(s):  
Nasmi Herlina Sari ◽  
S. Sinarep
Keyword(s):  
Modulus Of Elasticity ◽  
Bending Strength ◽  
Volume Fraction ◽  
Fiber Composite ◽  
Standard Test ◽  
Bending Test ◽  
Test Machine ◽  
Test Results ◽  
Fiber Volume ◽  
Nylon Fiber

The development of composite materials in the field of engineering is increasingly being used. This is because of its properties are superior compared to conventional materials, as the ratio between strength and density are quite high, stiff, the manufacturing process is very simple and resistant to corrosion and fatigue loads. The purpose of this study was to determine the effect the addition of nylon fibers with Epoxy Matrix on the increase in bending strength of epoxy composites.  The objected of this study was the composite of nylon fiber, which is cut 12 mm nylon fiber with epoxy resin as a fastening material. Before performing an experiment testing the tensile fibers has done and known to the stress of 461.22 MPa. There are 3 variations of volume fraction In this experiment, those are volume fraction of 40%, 50%  and  60%, with 3 variation each.  Method in the manufacture of specimens with the way the mould press. Tools to test the specimen is bending test machine (servopulser). Specimens using a standard test of ASTM C 393-94. Bending test results showed that the nylon fiber composite with fiber volume fraction 40% stress of 787.16 MPa, modulus of elasticity of 1.06 GPa, volume fraction of 50% the stress of 902.01 MPa, modulus of elasticity of 1.08 GPa, and for 60% volume fraction of the stress of 950.02 MPa, modulus of elasticity of 0.99 GPa.

scholarly journals Effects of Shrinkage-Compensation on Mechanical Properties and Repair Performance of Strain-Hardening Cement Composite Materials

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Seok-Joon Jang ◽  
Sun-Woo Kim ◽  
Wan-Shin Park ◽  
Koichi Kobayashi ◽  
Hyun-Do Yun
Keyword(s):  
Mechanical Properties ◽  
Strain Hardening ◽  
Volume Fraction ◽  
Cement Composite ◽  
Structural Performance ◽  
Rc Beam ◽  
Test Results ◽  
Fiber Volume ◽  
Study Results ◽  
Shrinkage Compensation

This paper describes the effects of expansive admixture on the mechanical properties of strain-hardening cement-based composite (SHCC) mixtures. Also, this study investigates structural performance of reinforced concrete (RC) beam specimens repaired with SHCC and Ex-SHCC (SHCC with expansive admixture). In this study, SHCC and Ex-SHCC mixtures with two specified compressive strength values of 30 MPa and 60 MPa and the fiber volume fraction of 1.5% were investigated. The expansive admixture replacement ratio of 10% by cement weight was used in this study. The test results indicate that the compressive, tensile, and flexural strength values of the SHCC mixtures increased when expansive admixture was included in the mix; however, their toughness and ductility decreased. The study results also show that the application of both SHCC and Ex-SHCC mixtures to repair damaged RC beam specimens can lead to significant structural performance improvement by mitigating crack damage and increasing ductility.

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