scholarly journals The Effect of the Type and Amount of Synthetic Fibers on the Effectiveness of Dispersed Reinforcement in Soil-Cements

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3917
Author(s):  
Krystian Brasse ◽  
Tomasz Tracz ◽  
Tomasz Zdeb
Keyword(s):  
Cohesive Soil ◽  
Modulus Of Rupture ◽  
Polypropylene Fibers ◽  
Cement Composites ◽  
Test Results ◽  
Bending Tests ◽  
Synthetic Fibers ◽  
Flexural Tensile Strength ◽  
Soil Cement ◽  
The Matrix

The paper deals with mechanical properties of soil-cement composites made with non-cohesive soil and reinforced with dispersed fibers. The research was carried out on the basis of three soil-cement matrices whose compositions varied in terms of the volumetric fraction of cement paste and the water-cement ratio. Two types of polypropylene fibers were used as dispersed reinforcement: single fibrillated-tapes polypropylene fibers (SFPF) and bundles of coiled fibrillated-tapes polypropylene fibers (BCFPF). The fibers varied in terms of their length and mass fraction. The objective of the study was to assess the effect of the addition of fibers to soil-cement composites on their flexural tensile strength and on their behavior in the post-critical state. The studies were carried out after 28 days of curing. Bending tests were carried out to determine post-critical stress values σCMODi, stress values at which the matrix is destroyed (limit of proportionality) σLOP, maximum stress values transferred by the fibers σMOR (modulus of rupture), and total fracture energy Gf,tot as well as compressive strength. The test results obtained, and their analysis, indicate the significant impact of the dispersed reinforcement used on the performance of such composites during bending.

scholarly journals A Study of the Flexural Behavior of Fiber-Reinforced Concretes Exposed to Moderate Temperatures

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3522
Author(s):  
Marta Caballero-Jorna ◽  
Marta Roig-Flores ◽  
Pedro Serna
Keyword(s):  
Steel Fiber ◽  
Flexural Behavior ◽  
Polypropylene Fibers ◽  
Fiber Reinforced ◽  
Insulation System ◽  
Bending Tests ◽  
Synthetic Fibers ◽  
Three Point Bending ◽  
Lower Performance ◽  
Cracked Specimens

The use of synthetic fibers in fiber-reinforced concretes (FRCs) is often avoided due to the mistrust of lower performance at changing temperatures. This work examines the effect of moderate temperatures on the flexural strengths of FRCs. Two types of polypropylene fibers were tested, and one steel fiber was employed as a reference. Three-point bending tests were carried out following an adapted methodology based on the standard EN 14651. This adapted procedure included an insulation system that allowed the assessment of FRC flexural behavior after being exposed for two months at temperatures of 5, 20, 35 and 50 °C. In addition, the interaction of temperature with a pre-cracked state was also analyzed. To do this, several specimens were pre-cracked to 0.5 mm after 28 days and conditioned in their respective temperature until testing. The findings suggest that this range of moderate temperatures did not degrade the behavior of FRCs to a great extent since the analysis of variances showed that temperature is not always a significant factor; however, it did have an influence on the pre-cracked specimens at 35 and 50 °C.

Potential Use of Colloidal Silica in Cement Based Composites: Evaluation of the Mechanical Properties

2012 ◽  
Vol 517 ◽  
pp. 382-391 ◽  
Author(s):  
S.F. Santos ◽  
J.A. Rodrigues ◽  
G.H.D. Tonoli ◽  
A.E.F.S. Almeida ◽  
Holmer Savastano
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
Transition Zone ◽  
Colloidal Silica ◽  
Fiber Reinforcement ◽  
Modulus Of Rupture ◽  
Cement Composites ◽  
Silica Suspension ◽  
The Matrix ◽  
Potential Use

The properties of cement based composites depend not only on the properties of their individual components but also on their interfacial characteristics and transition zone between fiber and matrix. There has been a renewed interest in the use of cellulosic pulp as micro-fiber reinforcement in cement based composites. The addition of nanoparticles, such as colloidal silica, to fiber-cement could allow a better control of its microstructure and the enhancement of the matrix/fiber interface. The objective of this work is to evaluate the effects of colloidal silica on the microstructure and mechanical performance of cementitious matrices and fiber-cement composites. These cementitious materials were prepared with 0%, 1.5%, 3%, 5% and 10% w/w colloidal silica suspension content. Cementitious matrices without fibers were produced by vibration. Fiber-cement composites with unbleached Eucalyptus kraft pulp as a micro-fiber reinforcement were produced by the slurry dewatering technique followed by pressing. All composite materials were cured by water immersion. A splitting (Brazilian) test was carried out to determine the tensile strength of cementitious matrices. Mechanical behavior of the fiber-cement composites was evaluated via modulus of rupture and fracture toughness based on load-displacement curves (L-d curves) under continuous loading and 3-point bending arrangement. The energy of fracture was measured through a stable crack propagation test with SENB (single-edge notched bending) configuration also under a 3-point bending arrangement. The matrix with highest content of colloidal silica suspension (10% w/w) presented high values of water absorption and consequently presented the lowest splitting tensile strength. The average values of modulus of rupture and fracture toughness of fiber-cement tend to decrease with increasing colloidal silica content. However, the pullout mechanism increased significantly in the fiber-cement composites with additions between 3% and 10% w/w of colloidal silica suspension as compared to that without any addition, noted by degree of improvement in the energy of fracture and by scanning electron microscopy micrographs (SEM). These findings show the potential use of colloidal silica to improve the transition zone between the cellulosic fiber and the cementitious matrix. The results of this study show an important way to engineer and control the fracture process of the composites.

scholarly journals Fiber Surface Modification; Characterization of Rattan Fiber Reinforced Composite

2018 ◽  
Vol 7 (3.7) ◽  
pp. 113 ◽  
Author(s):  
Flora Elvistia Firdaus ◽  
M Dachyar
Keyword(s):  
Alkali Treatment ◽  
Fiber Surface ◽  
Crystalline Polymer ◽  
Test Results ◽  
Flexural Tensile Strength ◽  
Reinforced Composite ◽  
Petroleum Resources ◽  
The Matrix ◽  
Matrix Yielding

Increasing the awareness of global warming and the depletion of petroleum resources had made many researchers focuses on using natural materials such as rattan. Its an edible fibers  are prepared to reinforce matrix yielding composite products within the aid of epoxy based resin  and hardener which also perform  as catalyst. The fibres are previously conducted an alkali treatment, this was considered to enhance the cohessiveness of fibers to matrix. Silane and dimethylethanolamine (DMEA) as an adhesives booster is respectively added to the composite formula. The specific purpose of this research is to know the influence of addition of Silane and  DMEA to the final properties of composite; flexural, tensile strength, elongation at break, hardness, and thermal. From the test results it is found that Silane keeps the matrix amorphous, while the addition of DMEA formed crystalline polymer. The ultimate property of the composites are found also depends on fiber woven pattern. 

Mechanical Properties of 91% Tungsten Alloy

2007 ◽  
Vol 345-346 ◽  
pp. 1625-1628 ◽  
Author(s):  
Wei Dong Song ◽  
Hai Yan Liu ◽  
Jian Guo Ning
Keyword(s):  
Crack Initiation ◽  
Tensile Tests ◽  
Tungsten Alloy ◽  
Test Results ◽  
Bending Tests ◽  
Three Point Bending ◽  
Grain Sizes ◽  
Initiation And Propagation ◽  
Fracture Behaviors ◽  
The Matrix

The tensile tests and the three-point bending tests have been conducted to investigate the crack initiation and propagation and the fracture behavior of 91W-6.3Ni-2.7Fe with three kinds grain sizes of 1~3μm, 10~15μm and 30~40μm. SEM was introduced to analyze the grain sizes, the micro-defects, the deformations and the fracture behaviors of tungsten alloys. The test results show that under the same loading conditions, the crack initiation and the crack propagation are not only related to grain size, but also related to the contiguity of tungsten grains and the interface between the tungsten grains and the matrix.

Cement Composite Reinforced with Synthetic Fibers: Comparison of Three-Point and Four-Point Bending Test Results

2016 ◽  
Vol 827 ◽  
pp. 332-335 ◽  
Author(s):  
Jaroslav Topič ◽  
Jan Bartoš ◽  
Lubomír Kopecký ◽  
Karel Šeps ◽  
Zdeněk Prošek ◽  
...  
Keyword(s):  
Bending Strength ◽  
Cement Composite ◽  
Bending Test ◽  
Test Results ◽  
Recycled Pet ◽  
Bending Tests ◽  
Synthetic Fibers ◽  
Four Point Bending ◽  
Pet Fibers ◽  
Four Point Bending Test

Presented article deals with the influence of PET fiber production on the bending strength of cement-based composite when incorporated into the fresh mortar, and comparison of results of 3-point and 4-point bending test. Cement paste samples were reinforced with 2 wt. % of primary or recycled PET fibers. The bending test was performed on prismatic samples with dimension of 40 × 40 × 160 mm. It was found that samples with recycled PET fibers, compared to primary ones, exhibit a decrease in bending strength. In the case of 4-point bending tests, the samples with recycled PET fibers exhibited higher bending strength than reference samples without any fibers. However, in the case of 3-point bending tests, the samples with recycled PET fibers had lower bending strength than the reference ones. The results suggest that recycled PET fibers could be used as an alternative to reinforce cement-based composites.

Mechanical Behavior of Self-Compacting Soil-Cement-Sisal Fiber Composites

2014 ◽  
Vol 634 ◽  
pp. 421-432 ◽  
Author(s):  
A.P.S. Martins ◽  
F.A. Silva ◽  
R.D. Toledo Filho
Keyword(s):  
Raw Materials ◽  
Low Cost ◽  
Sisal Fiber ◽  
Fracture Mechanisms ◽  
Residual Soil ◽  
Cement Composites ◽  
Uniaxial Compression Strength ◽  
Soil Cement ◽  
The Matrix ◽  
Sisal Fibers

The aim of this research is the development and mechanical characterization of self-compacting soil cement composites with the incorporation of fly ash, metakaolin and sisal fibers. The mentioned composites, based on natural raw materials (raw earth and vegetable fibers), which are abundant in nature and have low cost and low environmental impact could be used as a more sustainable alternative than conventional industrialized materials for applications that don ́t require high structural performance (minimum strength equals to 2 MPa). A residual soil, constituted by 35% of fines and 65% of granular material was selected and the matrix was designed using a computational routine, based on the compressible packing model (CPM). The rheology of the matrix was adjusted by the slump flow test having as a target the spreading value of 600 mm. The matrix presented uniaxial compression strength of about 3.3 MPa after 28 days of curing. After 240 days of curing it was noticed an increase in the compressive strength to 7.5 MPa. This can be traced back to the pozzolanic reactions that takes place in the system. The soil cement composites were produced with three different sisal fiber contents: 0.5, 1.0 and 1.5% (in relation to the weight of dry soil) and a fiber length (Le) of 20 mm. Under compression, the incorporation of fibers has significantly influenced the post-peak behavior, increasing the toughness and the strain capacity. Under four point bending loading, the presence of fibers have contributed to increase the peak strength and the residual strength with expressive gains of toughness. The composites presented strength values as high as 1.8 MPa (1.0% of fibers) when they were subjected to bending loads. The use of sisal fibers as reinforcement modified the fracture mechanisms of the composites, changing it from a brittle to a ductile behavior.

Numerical-Experimental Assessment of the Arumã Fiber as Reinforcement to the Cementitious Matrix

2014 ◽  
Vol 600 ◽  
pp. 460-468
Author(s):  
Maria Gorett dos Santos Marques ◽  
João de Almeida Melo Filho ◽  
Julio Cesar Molina ◽  
Romildo Dias Toledo Filho ◽  
Raimundo Pereira de Vasconcelos ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Mechanical Performance ◽  
Experimental Tests ◽  
Cement Composite ◽  
Cement Matrix ◽  
Cement Composites ◽  
Experimental Assessment ◽  
Bending Tests ◽  
The Family ◽  
The Matrix

Composites of high mechanical performance reinforced by fibers need a well set arrangement of them in the matrix so that under reinforcement which they can be submitted, a desirable performance can be shown. Thus, the cement composite studied has a cement matrix which received a reinforcement made by arumã fibers, shaped in bidirectional frames distributed in three layers. Arumã is a typical plant from the Amazon, species from the genus Ischnosiphon polyphyllus, part of the family Marantaceae. This study had the purpose of assessing the cement composites mechanical behaviour from the bending tests in four points and puncture tests in sheets which were supported by the four edges. Having presented mechanical results, a numerical simulation was made through the SAP2000 NonLinear® software, with the aim to obtain a numerical computational model able to represent the composites behaviour up to the point where the loading reaches the greatest amount. The numerical results present a good correlation with those obtained in the experimental tests.

scholarly journals Mechanical Properties and Micro Mechanism of Nano-Clay-Modified Soil Cement Reinforced by Recycled Sand

2021 ◽  
Vol 13 (14) ◽  
pp. 7758
Author(s):  
Biao Qian ◽  
Wenjie Yu ◽  
Beifeng Lv ◽  
Haibo Kang ◽  
Longxin Shu ◽  
...  
Keyword(s):  
Shear Strength ◽  
Void Ratio ◽  
Soil Mass ◽  
Direct Shear ◽  
Test Results ◽  
The Sustainable Development ◽  
Direct Shear Tests ◽  
Soil Cement ◽  
Nano Clay ◽  
New Material

To observe the effect of recycled sand and nano-clay on the improvement of the early strength of soil-cement (7d), 0%, 10%, 15% and 20% recycled sand were added. While maintaining a fixed moisture content of 30%, the ratios of each material are specified in terms of soil mass percentage. The shear strength of CSR (recycled sand blended soil-cement) was investigated by direct shear test and four groups of specimens (CSR-1, CSR-2, CSR-3 and CSR-4) were obtained. In addition, 8% nano-clay was added to four CSR groups to obtain the four groups of CSRN-1, CSRN-2, CSRN-3 and CSRN-4 (soil-cement mixed with recycled sand and nano-clay), which were also subjected to direct shear tests. A detailed analysis of the modification mechanism of soil-cement by recycled sand and nano-clay was carried out in combination with scanning electron microscopy (SEM) and IPP (ImagePro-Plus) software. The test results showed that: (1) CSR-3 has the highest shear strength due to the “concrete-like” effect of the incorporation of recycled sand. With the addition of 8% nano-clay, the overall shear strength of the cement was improved, with CSRN-2 having the best shear strength, thanks to the filling effect of the nano-clay and its high volcanic ash content. (2) When recycled sand and nano-clay were added to soil-cement, the improvement in shear strength was manifested in a more reasonable macroscopic internal structure distribution of soil-cement. (3) SEM test results showed that the shear strength was negatively correlated with the void ratio of its microstructure. The smaller the void ratio, the greater the shear strength. This shows that the use of reclaimed sand can improve the sustainable development of the environment, and at the same time, the new material of nano-clay has potential application value.

scholarly journals Multi-Scale Study of The Small-Strain Damping Ratio of Fiber-Sand Composites

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2476
Author(s):  
Haiwen Li ◽  
Sathwik S. Kasyap ◽  
Kostas Senetakis
Keyword(s):  
Dynamic Properties ◽  
Wide Spectrum ◽  
Damping Ratio ◽  
Polypropylene Fiber ◽  
Small Strain ◽  
Treatment Method ◽  
Fiber Content ◽  
Polypropylene Fibers ◽  
Test Results ◽  
Fiber Reinforced

The use of polypropylene fibers as a geosynthetic in infrastructures is a promising ground treatment method with applications in the enhancement of the bearing capacity of foundations, slope rehabilitation, strengthening of backfills, as well as the improvement of the seismic behavior of geo-systems. Despite the large number of studies published in the literature investigating the properties of fiber-reinforced soils, less attention has been given in the evaluation of the dynamic properties of these composites, especially in examining damping characteristics and the influence of fiber inclusion and content. In the present study, the effect of polypropylene fiber inclusion on the small-strain damping ratio of sands with different gradations and various particle shapes was investigated through resonant column (macroscopic) experiments. The macroscopic test results suggested that the damping ratio of the mixtures tended to increase with increasing fiber content. Accordingly, a new expression was proposed which considers the influence of fiber content in the estimation of the small-strain damping of polypropylene fiber-sand mixtures and it can be complementary of damping modeling from small-to-medium strains based on previously developed expressions in the regime of medium strains. Additional insights were attempted to be obtained on the energy dissipation and contribution of fibers of these composite materials by performing grain-scale tests which further supported the macroscopic experimental test results. It was also attempted to interpret, based on the grain-scale tests results, the influence of fiber inclusion in a wide spectrum of properties for fiber-reinforced sands providing some general inferences on the contribution of polypropylene fibers on the constitutive behavior of granular materials.

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