Effect Of Polypropylene Fibers Research Articles

Effect of polypropylene fibers on the bond-slip performance of HSS bars in HPC and UHPC

To control the structural performance of reinforced concrete (RC) members, enough bonding between rebars and concrete should be provided. Different parameters affect the bond interaction between rebars and concrete. This investigation tends to assess the bonding resistance behaviour of high-strength steel (HSS) bars in concrete considering the effect of two types of concrete: high-performance concrete (HPC) and ultra-high-performance concrete (UHPC). In addition to the type of concrete, the effect of fibers incorporation is measured. For this aim, a total of thirty-six specimens were cast and evaluated. Two diameters (12 mm and 16 mm) and three embedded lengths (1, 2, and 3 times the diameter of rebars) were also used, and the impact of the rebar’s diameter and embedded length on the load-bearing capacity, stress and slip of rebars were examined. To boost the bonding characteristics of reinforcements, three various polypropylene fibres (PF) contents were added: 0%, 0.5% and 1%. A pull-out test was carried out on samples. In addition, the obtained results and previous models proposed by literature have been employed to generate new models to predict the bond-slip characteristics of HSS bars in HPC and UHPC when different PF contents are incorporated. The results showed that the maximum peak of slip between the HSS bars and concrete deteriorated with the utilisation of PF, and this peak declined more for UHPC. Additionally, the load capability of specimens was significantly enhanced when PF were added. Finally, the model suggested in this paper may be used to forecast the ultimate stress and bond-slip characteristics of HSS bars in conventional and PF-reinforced HPC and UHPC, with a good level of correctness with the experimental results.

Effect of Polypropylene Fibre on Self- Compacting High-performance Concrete

This study conducted tests on the design mixture of Polypropylene Fibre Reinforced Self-Compacting High-performance Concrete (PFRSCHPC) and Self-Compacting high-performance concrete (SCHPC) to determine the mechanical properties of the concrete, and the beams behaviour under bending loads. The composition of the mixtures of PFRSCHPC and SCHPC refer to Oesman, et al. (2022), which conducted research on UHPC (ultra-high-performance concrete) using natural sand and crushed stone through a 4.75mm sieve. PFRSCHPC and SCHPC compositions using Portland Slag Cement (PSC); 1% superplasticizer and 30% silica fume of the total binder; 1% Polypropylene fibre (PP); the ratio of� sand to crushed stone 45%: 55%; and the w/b was 0.23. However, SCHPC as the control concrete mixture does not contain PP. The testing results of the PFRSCHPC showed compressive strength, tensile strength, flexural strength, and modulus of elasticity were 42.73 MPa; 4.33 MPa; 8.98 MPa; 45.51 GPa, respectively. When compared to SCHPC, PP has an influence in increasing tensile strength by 2.38 MPa (122.05%), flexural strength by 2.67 MPa (42.77%), and concrete elasticity modulus by 6.67 GPa (17.32%). However, 1% PP decreased compressive strength of PFRSCHPC, lower by 4.93 MPa (10.34%) compared to SCHPC. PFRSCHPC beam reached a peak load of 27.5 kN; initial stiffness of 5.32 kN/mm; ductility of 5.6; and toughness of 1606.08 kNm. PFRSCHPC beam with PP fibre content of 1% are able to increase 17.02% of peak load; 14.75% of ductility, and 113.91% of toughness.

Effect of polypropylene fiber and nano-silica on the compressive strength and frost resistance of recycled brick aggregate concrete

Abstracts Wasted clay bricks as coarse aggregate of recycled concrete is an effective solution to save energy and reduce CO2 emissions in the construction industry. However, the mechanical properties and frost resistance of recycled brick aggregate (RBA) concrete are inferior to those of ordinary concrete, which limits its widespread application. In this research, the effects of RBA, polypropylene fiber (PPF) and nano-silica (NS) on the mechanical properties and frost resistance of concrete were investigated. The effect of RBA, PPF, and NS on the compressive strength was quantitatively analyzed, and microstructural analysis and fractal dimension calculation of the concrete were performed. The results show that the concrete compressive strength decreased with the increase in RBA replacement rate, and it was effectively improved by adding PPF and NS (PPF-NS). The compressive strength first increased and then decreased with the increase in PPF and NS. The improvement effect of 0.12% PPF and 2% NS on the compressive strength of 50% replacement rate of RBA concrete was most effective. The gray relational degrees between the compressive strength and RBA, PPF, and NS were 0.6578, 0.8297, and 0.5941, respectively. The frost resistance of PPF-NS modified concrete was better than that of ordinary concrete, mainly manifested in its superior apparent phenomena, mass loss, and strength loss. Compared with normal concrete, the microstructure was denser and the fractal dimension of the cross-section was higher for RBA concrete modified with PPF-NS before and after freeze–thaw cycles.

The Effect of Polypropylene Fiber and Glass Fiber on the Frost Resistance of Desert Sand Concrete

The Effect of Polypropylene Fiber and Glass Fiber on the Frost Resistance of Desert Sand Concrete

Effects of polypropylene fibers and aggregate contents on the impact performance of coral aggregate concrete

The paper aims to study the effect of polypropylene (PP) fibers and aggregate contents on the impact compression mechanical performance of coral aggregate concrete (CASC). 5 PP fiber contents (0 kg/m3, 1 kg/m3, 2 kg/m3 3 kg/m3, 4 kg/m3), 3 natural gravel replacement ratios (0 %, 40 %,70 %), and 3 impact pressures (0.10 MPa, 0.12 MPa, 0.14 MPa) were designed for the split Hopkinson pressure bar (SHPB) test herein. The PP fiber contents and gravel replacement ratios effects on the impact compressive properties of CASC were assessed in term of the stress-strain curve, the strain rate effects and the toughness. The results showed that the dynamic compressive strength enhanced obviously with the increasing PP fiber contents and gravel replacement ratio, while the excessive fiber can degrade its properties instead. There exists the apparent strain rate effect of dynamic compressive strength and dynamic increase factor. The addition of PP fiber and the gravel can also improve the toughness of CASC and weaken the strain rate sensitivity. Eventually, the dynamic constitutive model based on ZWT constitutive model was established by considering the material damage, which can excellently forecast the dynamic stress-strain curve of CASC and the dynamic mechanical properties.

The Effect of Polypropylene Fibers on the Behavior of Fiber Self-Compacting Concrete

Fiber self-compacting concrete (FSCC), is a concrete that has been combined with fiber in its mix design. Extensive benefits of self-compacting concrete (SCC) in full fill the mold and achieving full compaction without vibration, with good behavior after concrete cracking, raise the idea of self-compacting concrete production. The fundamental challenge in this area is the unsatisfactory performance of concrete with fibers; In other words, using fibers in concrete will reduce concrete fluidity. Therefore, determining the appropriate percentage of fibers in SCC can be a precursor to extending the use of FSCC. In this study, polypropylene fibers with 0.5, 1, 0.1, and 2% of concrete mix design have been added to the self-compacting concrete mix design. Its impact on the performance of concrete has been evaluated using time and diameter of slump-flow, L-Box, J-ring, and V-funnel flow time tests. Based on the criteria defined by EFNARC standard, it was indicated that the FSCC containing 0.5% polypropylene fibers has an acceptable performance. Additionally, the effect of polypropylene fiber on the mechanical properties of hardened concrete has been studied using compressive strength and tensile tests and shown that changes in FSCC compressive strength and tensile with 0.5% polypropylene fiber are negligible.

Effect of polypropylene fibres on strength and durability performance of M-sand self compacting concrete

Effect of polypropylene fibres on strength and durability performance of M-sand self compacting concrete

Experimental study on bonding performance of polypropylene fiber modified rubber concrete and deformed steel bar

In order to study the binding properties of deformed steel rods and rubber concrete modified with polypropylene fiber, four groups of bonding specimens were designed with polypropylene fiber volume ratio as a variable. The effect of polypropylene fiber on bond strength and bond slip curve was investigated by drawing test. It was found that the bond strength increased with the increase of polypropylene fiber volume fraction in the range of 0 ~ 1.5 %. Based on the experimental data, the constitutive relationship between deformed steel bar and polypropylene fiber modified rubber concrete was established. It provides a theoretical basis for further research on polypropylene fiber modified rubber concrete.

The Effect of Polypropylene Fibers on the Fracture Characteristics of Lightweight Aggregate Crumb Rubber Concrete Composites

The increasing use of rubber tires and their low recycling ratio have made them a serious environmental problem. This work aims to develop and investigate enhanced lightweight aggregate crumb rubber concrete (PFLWACRC) composites regarding the fracture properties of concrete. Polypropylene (PP) fibers are commonly familiar with increased crack growth endurance of concrete. On the other hand, the reuse of waste rubber in concrete plays a major role in the mitigation of the effects of climate change. Various concrete mixtures were designed with conventional Portland cement and common lightweight coarse aggregates. The variables considered in this study are PP fibers in different percentages (0.2%, 0.4%, and 0.6% volume fraction), and crumb rubber with various substitution proportions (0%, 5%, 10%, 15%, 20%, and 25% of fine aggregates). Cement with 450kg/m3 density with 10% silica fume was used. The fracture characteristics, which involve fracture toughness (KIC) and fracture energy generation (GF), of all concrete mixtures were evaluated by testing two types of samples, i.e. 54 notched concrete beams with dimensions of 10×10×52cm and 54 cylinders with diameter×height equal to 15×30cm. The results showed that the fracture toughness generation addresses the energy scattering limit of concrete mixtures. The findings showed that the existence of PP fibers increased the fracture energy and critical Crack Mouth Opening Displacement (CMOD)c. The PP fibers had a limited effect on the compressive strength and may even reduce it, but a remarkable enhancement of the energy absorption was observed.

The effect of polypropylene fiber on the mechanical properties between hybrid fiber geopolymer concrete and geopolymer concrete in elevated temperature

This paper has influence on discovering the behavior of hybrid polypropylene fiber reinforced geopolymer concrete under constant and elevated temperature with the purpose to determine the mechanical properties of the material. While the expertise and acquaintance with concrete behavior under constant temperature are well known, the behaviour under elevated temperature has to be seriously explored. This study objectives is to match between the mechanical properties of unburnt and burnt fiber reinforced geopolymer concrete. This study uses experimental investigation. Compression and splitting tensile tests were conducted on the 150 mm cilinder mold. Meanwhile, flexural tension test was conducted on 100 mm x 100 mm x 450 mm rectangular mold. The result of both materials, without set fire to and with set fire to, are analyzed. The gained findings for burnt material are the compression test value cut down, otherwise, the splitting tensile test and flexural tensile strength grade increase.

Effect of polypropylene fibers on internal erosional behavior of poorly graded sandy soil stabilized with the binary mixtures of clay and polyvinyl acetate

Effect of polypropylene fibers on internal erosional behavior of poorly graded sandy soil stabilized with the binary mixtures of clay and polyvinyl acetate

The Effects of Polypropylene Fibers on the Mechanical and Durability Performance of a Roller Compacted Concrete for Pavement

The Effects of Polypropylene Fibers on the Mechanical and Durability Performance of a Roller Compacted Concrete for Pavement

The Effect of Polypropylene Fiber and Steel Fiber on Geopolymer Concrete

One of the environmentally friendly concrete as an alternative to cement concrete in the future is geopolymer concrete which used a cement substitute in the form of fly ash. To prevent premature cracking of the concrete, this study added fiber types such as polypropylene fiber, and steel fiber (dramix), this experiment with 3 variables namely the addition of polypropylene fiber by 0%, 0.40%, 0.80%, 1.2%, steel fiber of 0.25%, 0.50%, 0.75%, 1.00%, as well as a combination of polypropylene fiber and steel fiber (0.4%P;0.50%D), (0.8%P;0.75%D), (1.2%P;1.00%D) of the weight of the concrete. In this study, using a beam specimen measuring 10x10x50 cm, for each percentage of fiber usage there are 2 beam trials. Geopolymer concrete in this study uses a ratio of NaOH and Na2SiO3 is 2:1 and a constant concentration of 10 Molar, to test the Flexural Strength Test of Concrete at the age of 28 days of concrete. The results of the highest average flexural strength of geopolymer concrete without fiber σl = 78.77 kg/cm2, using polypropylene 0.80% σl =50.50 kg/cm2, and 0.25% steel fiber σl =68.87 kg/cm2, the combination of both fibers (P0.4%; D0.25%) σl =65.34 kg/cm2. These results do not produce good workability, thus affecting the decrease in flexural strength. By increasing the ratio A = 0.35 to 0.45, the geopolymer concrete mix produces better workability with the highest average flexural strength of geopolymer concrete with polypropylene fiber 0.8% σl = 80.107 kg/cm2.

Effect of Polypropylene Fibers on Swelling Potential and Shear Strength of Clay

Expansive clays can cause major problems for urban development (roads, railways, infrastructure, etc.); therefore, reducing the swelling potential of clays has always been a concern in the geotechnical field. The presented paper investigates the effect of polypropylene reinforcement fibers on the swelling potential and shear strength of clay. The samples studied were taken from the clayey region of Mila, located in the northern east of Algeria. The experimental procedure adopted in this research consists first of the assessment of the physical, mechanical, and mineralogical characteristics of the soil samples without reinforcement. Then, swelling pressure, swelling rate, and swelling index are used to assess the swelling potential of these samples. After the reinforcement using a variety of polypropylene fiber concentrations (2 to 6% of the weight of the dry clay), the free swelling is clearly reduced. The optimum reinforcement rate in this case is 4%, in which the swelling was reduced by 90.7%. Finally, to offer more insights regarding the impact of clay reinforcement using polypropylene fibers, the effect of this later on the mechanical properties of the studied clay was also analyzed through the tangential shear strength. It was found that the polypropylene fibers increased the tangential shear resistance of Mila’s clay. Doi: 10.28991/CEJ-2023-09-03-04 Full Text: PDF

Effect of polypropylene fiber on early-age properties and stress relaxation of ultra-high-performance concrete under different degrees of restraint

This paper aimed to investigate the effect of polypropylene (PP) fibers on mechanical properties, shrinkages, cracking potential, and stress relaxation of ultra-high-performance concrete (UHPC) at early age. The proportion of PP fibers was 0%, 1%, 2%, and 3% by the volume of concrete. Two types of restrained ring specimen (DR-1 and DR-2) were also employed to consider the effect of degrees of restraint. The results indicated that the cracking age of UHPC with PP fiber proportion from 0% to 2% was postponed, but further incorporation of PP fibers showed the inconspicuous benefits. Relaxed stress decreased with the incorporation of PP fibers. Moreover, the difference of stress relaxation was less pronounced between UHPC with 1% and 2% PP fibers. The influential factors for stress relaxation were analyzed. Both DR-1 and DR-2 demonstrated a high degree of restraint. This was attributed to the dominant role of autogenous shrinkage in total free shrinkage of UHPC, which eclipsed the effect of volume-to-surface ratio of specimen.

Experimental Study on Impact Behavior of Concrete Panel with and without Polypropylene Macrofibers

Macrofibers have often been used to increase the tensile strength, durability, crack resistance, spalling, impact resistance, and toughness of concrete. However, the impact behavior of fiber-reinforced concrete (FRC) structures is quite different from their static behavior, and the effectiveness of macrofibers in improving impact resistance should be carefully evaluated. In this study, the impact behavior of FRC with polypropylene (PP) macrofibers was studied through a series of drop-weight impact tests. First, the material characteristics of the FRC with PP fibers under static conditions were evaluated. Test specimens were constructed and drop-weight impact tests were performed. The main parameters were the presence or absence of PP fibers and the drop height, which is related to the magnitude of the impact energy. From the results, it can be found that the crack width of the FRC specimen was smaller than the normal concrete specimen for a similar residual deflection after the impact test due to the bridging effect of the macrofibers. However, the effect of PP fibers on the impact resistance was not significant, even though there was a considerable increase in tensile and flexural performance under static conditions, since the hardening effect after the sharp reduction in strength shown in the static test of FRC is not effective in the impact test.

The effect of polypropylene fiber on the curing time of class G oil well cement and its mechanical, petrophysical, and elastic properties

The cement paste is subjected to various loads throughout a well’s life, which may compromise some of its essential characteristics and impair its performance. When the cement paste is first being formed and the cement’s characteristics have not yet fully matured, these loadings take on greater importance. In this study, the early properties of cement used in oil wells that contains polypropylene fiber are assessed. Five different curing times were used to prepare ten cement samples (6, 12, 24, 48, and 72 h). Five samples contained polypropylene fiber, while the remaining five samples were without polypropylene fibers. After the samples were prepared, the examination of several early cement properties took place. Nuclear magnetic resonance (NMR) was used to describe each sample in order to determine how the curing times affected the cement’s porosity. The findings demonstrated that both cement systems’ compressive and tensile strengths increased with curing time, and that adding polypropylene fiber enhanced the cement’s strength. The porosity and permeability of the cement specimens were significantly reduced with the incorporation of polypropylene fibers, as well as with time during the curing process for both cement samples. The reduction of Young’s modulus and the increase in Poisson’s ratio show that the addition of polypropylene fibers also makes the cement more elastic. To express variations in porosity as well as compressive and tensile strengths, logarithmic relationships were constructed. While the Poisson’s ratio, Young’s modulus, density variations, and permeability were precisely modeled by power-law equations.

Effect of polypropylene fibre on cementitious mortar early shrinkage cracking using the eccentric-ring test

The effects of polypropylene fibres on mortar and cement-paste cracking were investigated using different amounts of fibre fractions and eccentric rings under restrained-shrinkage conditions. Eccentric-ring tests were conducted to investigate early-age shrinkage cracks. The characteristics of restricted cementitious materials were described by evaluating the cracking time and using concrete mixtures that are less likely to crack. Different fibre-volume fractions significantly enhanced the width, area, and age of cracking. Increasing the water-cement ratio and sand percentage increased the cracking age. The eccentric-ring test showed a greater susceptibility to cracking in cement-mortar composites. The mechanical strength was assessed, and the impact of polypropylene fibres was investigated.

Effect of polypropylene fiber on workability and strength of fly ash-based geopolymer mortar

Geopolymers do not require Portland cement as a binder; hence, the binder is replaced by a material containing high SiO2 and Al2O3 reacted with an alkaline activator (NaOH and Na2SiO3). In addition, mortar or concrete is highly susceptible to cracking, requiring the addition of polypropylene fiber (PPF). This research belongs to an experimental study examining the addition of PPF with percentages from 0%, 0.25%, 0.5%, 0.75%, and 1% by utilizing coal fly ash (FA) as a precursor. This study also added a superplasticizer (SP) and extra water (EW) to maintain the flowability. The tests were carried out on the workability, strengths, and microstructure of geopolymer mortar. Workability obtained values of 140 - 220 mm. Furthermore, the highest compressive strength of 73.3 MPa and flexural strength of 9.92 MPa were identified in the geopolymer mortar with the addition of 0.5% PPF. In addition, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) tests were applied to investigate the geopolymer microstructure.

Influence of Erosion Induced by NaCl on the Mechanical Performances of Alkali-Activated Mineral Admixtures

In this paper, the influence of NaCl freeze-thaw (F-T) cycles and dry-wet (D-W) alternations on the flexural, compressive and bonding strengths of alkali-activated fly ash (FA) and a blast furnace slag powder (BFS) is investigated. The considered NaCl concentration is 3%. The effect of polypropylene fibers on the mechanical strengths is also examined. Scanning electron microscopy (SEM), thermogravimetry (TG) and X-ray diffraction (XRD) are selected to discern the mechanisms underpinning the NaCl-induced erosion. The obtained results indicate that the best results in terms of material resistance are obtained with admixtures containing 60% BFS and 40% FA in terms of mass ratio and 3% polypropylene fibers in terms of volume ratio. The maximum rates of decrease of the flexural, compressive and bonding strengths after 300 NaCl F-T cycles are 21.5%, 20.3% and 22.6%, respectively. The corresponding rates of decrease due to NaCl D-W alternations are 28.1%, 26.1% and 31.5%, respectively. The TG curves show that the alkali-activating activity of BFS is higher than that of FA. Moreover, in the first case, the microstructure of the hydration products is more compact. The results also show that NaCl F-T cycles lead to increasing cracks in the alkali-activated BFS.