Addition Of Polypropylene Fibers Research Articles

Талшықтардың бетонның беріктік сипаттамаларына әсерін бағалау

The article presents the results of research of different fibers on the effect of strength characteristics of fine-grained concrete. The basic characteristics of the types of fibers used for the manufacture of fiber concrete are given. The results of laboratory research of polypropylene and basalt fibers for dispersion reinforcement of concrete are given. To estimate the strength changes the samples were made and tested in compression at the age of 3, 14 and 28 days of normal-moist hardening. The results of determining the compressive strength of fine-grained fiber concrete without adding fiber (control composition) and with the addition of polypropylene fiber 0.1, 0.5, 1.5, 2.5% of the mass of cement and basalt fiber 0.05, 0.1, 0.2, 0.5% of the mass of cement are given. It is shown that the most optimal limits of the introduction of polypropylene fiber in the mixture can be considered 0.5% of the weight of cement, which leads to an increase in compressive strength up to 9.09%, compared with the control composition. The introduction of basalt fiber in the mixture of fine-grained concrete in an amount of 0.1% of the weight of cement can increase the compressive strength by 11.4%.

Mechanical properties of short polypropylene fiber enhanced recycled concrete under cyclic compression

AbstractThis study investigated the mechanical properties and stress–strain relationship of polypropylene fiber recycled aggregate concrete (PFRAC) subjected to uniaxial cyclic compression. A total of 78 cylindrical specimens were designed for uniaxial cyclic compression test with coarse aggregate replacement rate, polypropylene fiber volume fraction, and loading rate as variation parameters. The failure process of the specimens under cyclic loading was observed and recorded. The stress–strain curve of PFRAC was summarized. The important mechanical properties of PFRAC were obtained, such as plastic strain, accumulated energy dissipation. The microstructure of PFRAC was analyzed by scanning electron microscopy, and the crack resistance mechanism of PFRAC under cyclic loading was revealed. The results show that the PFRAC under cyclic loading appeared oblique splitting failure. The compressive stress–strain curve envelope of PFRAC subjected to cyclic loading exhibited similarity to the monotonic counterpart. The addition of polypropylene fibers can improve the peak stress, peak strain, residual stress, post‐peak ductility, and accumulated energy dissipation of the recycled concrete. In addition, a constitutive relation formula for the PFRAC stress–strain curve under cyclic loading is proposed, and the fitting result is good.

Prediction of chloride ion concentration distribution in basalt-polypropylene fiber reinforced concrete based on optimized machine learning algorithm

The distribution characteristics of chloride ion concentration in basalt-polypropylene fiber reinforced concrete (BPFRC-CC) are important for assessing the durability of concrete structures under marine environment. This study collected the distribution data of BPFRC-CC in three different environments: tidal, submersible, and salt spray. Several optimized machine learning models were developed to predict the distribution of BPFRC-CC. The performance of these models was evaluated based on a comparison between actual and predicted values, residual distribution histograms, and performance indicators. The research results of this article showed that the particle swarm optimization support vector regression (PSO-SVR) model exhibits significant accuracy and generalization ability, with closer proximity to the actual values in both the training and testing sets. The residual distribution histogram of the PSO-SVR model approximated a normal distribution with a smaller mean and standard deviation. Evaluation indicators, including R2, MSE, RMSE, MAE, and MAPE, for the PSO-SVR model were 0.994, 6.92e-5, 0.0083, 0.0062, and 0.0453, respectively. The SHAP values revealed that depth and age were the most critical influencing factors. The decrease in age, water-cement ratio, and water-binder ratio, the addition of basalt fibers and polypropylene fibers, and the increase in depth reduced the BPFRC-CC. In addition, BPFRC-CC in tidal, salt spray, and submersible areas decreased in that order. Finally, a graphical user interface for BPFRC-CC was developed, providing researchers and production personnel with an intuitive, efficient, and visual production experience. This study has important implications for the optimization of BPFRC formulations and the prediction and assessment of the life of BPFRC structures.

Combined Effect of Colemanite and Polypropylene Fiber on Properties of Cement Mortar

Turkey is one of the richest countries in the world in terms of boron mineral reserves. The most commercially used boron mineral in Turkey is colemanite. Although there are some studies on the use of colemanite in concrete, there is still a gap in the literature. In this study, first of all, the use of colemanite in mortar samples was investigated by substituting different ratios of colemanite for cement. In addition, polypropylene fiber was added in different ratios by volume, and an evaluation was made on the combine effect of colemanite and fibers on mortar samples. For this purpose, colemanite was substituted for cement in mortar samples at 5% and 10% cement by weight. Polypropylene fibers were added to the mortars produced with colemanite at a rate of 0.4% and 1.2% by volume. In the study, flow tests, capillarity, water absorption, flexural, compressive, and ultrasonic velocity tests were performed on mortar samples, respectively. According to the test results, it was observed that the flow values of the mortar samples produced with colemanite increased compared to the control mixture. It was found that the addition of 10% colemanite instead of cement negatively affected the capillarity, water absorption, flexural and compressive strength, and UPV values of the mortar specimens. 5% colemanite addition had a lower negative effect. 0.4% polypropylene fiber addition resulted in a positive change in the compressive strength and capillarity values compared to the non-fiber specimens.

Mechanical Properties of Cement Mortars Reinforced with Polypropylene Fibers Subjected to High Temperatures and Different Cooling Regimes

This study experimentally investigated the mechanical properties of cement mortars that were reinforced with polypropylene (PP) fibers after being exposed to high temperatures and cooled under different regimes. PP fibers were added in amounts of 2, 3 and 4 kg/m3, the residual strengths of the mortars exposed to various temperatures up to 500 °C and cooled under different regimes were determined. It was found that the addition of PP fiber at the level of 2 kg/m3 improves the residual flexural and compressive strengths up to 300 °C. The residual flexural strength was approximately 75%, which is 15% higher than that observed in the simple mortar, and the same happens with the residual compressive strength which was approximately 85%, which is 17% higher than that observed in the simple mortar, regardless of the types of cooling used on the specimens. It was determined by means of a statistical analysis that there are no significant differences in the mechanical properties of the mortar according to the cooling regimes used, after having been exposed to high temperatures. The correlation of the residual flexural and compressive strengths was achieved with a coefficient of determination, R2 = 0.82, and the relationships between the variables were considered acceptable regardless of the types of cooling used.

Production Economical Reinforced Concrete Slabs using Eco-Friendly Material

Concrete is a material that is strong in compression but weak in tension. To overcome this issue, reinforcement must be used to improve the tensile strength of the concrete. However, it is acknowledged that steel has its drawbacks, such as the fact that it has a high cost and corrosion potential, and the rebar is heavy, non-renewable, and non-environmentally friendly. Thus, this experimental study investigates the potential product of economical reinforced concrete slabs using eco-friendly materials. Firstly, to enhance the concrete properties, a compressive, tensile, and flexural test, also a concrete with the addition of polypropylene fiber outlasted the control mix design in terms of strength and durability. The results included the control mix (CM), F1 0.25%, F2 0.50%, F3 0.75%, and F4 1%. The specimen with the highest compression and tensile strength was 24.28 MPa and 3.15 MPa, respectively, for the F1 specimen with 0.25% short fibers. Secondly, the bending test was carried out on ten slabs to check the structural behavior of these slabs reinforced with reed rods as the eco-friendly material. The good results of the bearing capacity of a partially reinforced concrete slab with a reed have been obtained at 23.8 kN. Meanwhile, to obtain better results, this research has enhanced the behavior of the concrete slab by improving the concrete's properties by adding polypropylene synthetic microfiber to the mixed concrete. In addition, giant reeds treated with epoxy increase the bonding strength with concrete, improve tensile strength properties, and reduce the absorption of reeds. Therefore, the bearing capacity results of the reed-reinforced concrete slab became the best, which were 35.83 kN. Thus, reinforcement of one-way slabs by reed partially with appropriate diameters could be substituted to obtain good performance in the reconstruction of low-cost buildings. As a result, economical reinforced concrete slabs have been produced using eco-friendly materials. Doi: 10.28991/CEJ-2023-09-06-010 Full Text: PDF

The Impact of Polypropylene Fibre Addition on the CBR Value

The Impact of Polypropylene Fibre Addition on the CBR Value

The effects of steel, polypropylene, and high-performance macro polypropylene fibers on mechanical properties and durability of high-strength concrete

Present study aimed to compare the properties of high-strength and ordinary concrete containing polypropylene fibers (PPFs), high-performance synthetic macro polypropylene (HPP) fibers, and steel fibers (SF) under standard and sulfate curing conditions. The high-strength concrete with water-to-cement ratios of 0.38, 0.33, and 0.28 were tested. The addition of PPF and SF reduced the workability of these mixtures containing supplementary cementitious material. The highest compressive strength belongs to the mixture containing 1% of SF and 0.2% of PPF. The highest tensile strength belongs to the mixture containing 0.5% of HPP fibers with 1% of SF and 0.2% of PPF. The highest flexural strength of the mixture containing 0.5% of HPP fibers with 1% of SF. Fiber- reinforced concretes have less 30-minute water absorption than non-fiber samples. The minimum absorption belongs to the sample containing 0.5% of PPF with 20% of silica fume in the amount of 0.53%.

Performance of polypropylene reinforced self-compacting concrete

The last 10 years have seen tremendous growth in RCC, with both population growth and changes in construction methods playing a significant role. Self-compacting concrete (SCC) selection is largely influenced by the site's features, the construction's type (particularly the choice of columns and beams), and the arrangement of reinforcement. The productivity may be maximised by utilising vibrators to eliminate vibration compaction. While using SCC, concrete's performance, hardened attributes such surface quality, strength, and durability are most significantly impacted. The goal of this research is to look into the effect of Polypropylene (PF) reinforcing on the hardened concrete qualities of M30 grade SCC. In order to create mixtures with different fibre content fractions (0, 0.5, 1.0, 1.5, & 2.0 percent), a fixed amount of fly ash (25 percent) was substituted for cement by weight. The slump flow, V-Funnel, L-Box, and J-Ring tests are used to analyse fresh properties in the laboratory. Investigations are conducted on the hardened characteristics' compressive strength at 7 and 28 days, split tensile strength at 7 and 28 days, flexural strength at 7 and 28 days, resistance to acid attack at 7 and 28 days, and water absorption. Polypropylene fibres were used to achieve the highest compressive strength, which was 11.6 percent. When compared to self-compacting concrete without polypropylene fibres, the split tensile strength improved by up to 17.8 percent. The flexural strength of PF is around 15% greater, and they absorb less water.The addition of polypropylene fibres also impeded the acid attack statistics, but when we look at these results alone, we observe that all mixes acquire self-compacting characteristics utilising PFwith a fibre concentration of up to 1.0 percent. Concrete's mechanical characteristics were enhanced and its excellent endurance was shown by polypropylene fibres.

Study and Microanalysis on the Effect of the Addition of Polypropylene Fibres on the Bending Strength and Carbonization Resistance of Manufactured Sand Concrete.

To popularize the complete replacement of natural sand with manufactured sand, a study was performed to determine the effect of adding polypropylene fibres (PPFs) to increase the bending strength and carbonization resistance of manufactured sand concrete (MSC). A 2 × 3 factorial design with the content and length of PPF as variables was used to establish a carbonization depth prediction model and a response surface model (RSM). The phase composition and microstructure of polypropylene-fibre-reinforced manufactured sand concrete (PPF-MSC) were analysed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show the addition of PPF with different contents and lengths increases the bending strength of PPF-MSC to varying degrees, while reducing the carbonization depth and increasing the dynamic elastic modulus after 28 days of carbonization. The highest bending strength (6.12 MPa) and carbonization resistance of PPF-MSC are obtained by the addition of 1 kg/m3 of 12 mm PPF, while the carbonization depth and an increase in the dynamic elastic modulus after 28 days of carbonization are maintained at a minimum of 2.26% and 1.94 mm, respectively. A prediction model was established to obtain a formula for the PPF-MSC carbonization depth in terms of the content and length of PPF and the carbonization time. The following results were obtained from the RSM: compared to the PPF length, the PPF content has a larger impact on the PPF-MSC bending strength and a smaller impact on the PPF-MSC carbonization resistance; there is no significant interaction between the content and length of PPF; and the predicted and measured values are close, indicating that the model is highly reliable. A comparison of the XRD patterns and SEM micrographs of PPF-MSC and MSC after 28 days of carbonization show a lower peak intensity of CaCO3 in the pattern for the carbonized area for PPF-MSC than for MSC and considerably fewer surface pores and cracks in PPF-MSC than in MSC. These results indicate that the addition of PPF increases the compactness of MSC and creates an effective resistance to the erosion by water molecules and carbon dioxide (CO2), thus enhancing the bending strength and carbonization resistance of MSC.

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.

Impact of Addition of Fly Ash (as Sand Replacement) and Polypropylene Fibers on Energy Absorption Characteristics of Foam Concrete

Abstract Foam concrete has recently piqued the interest of defense engineering because of its innovative properties of absorbing energy, softening impact, exhausting oscillation, and lowering stress amplitude behavior. However, only a few investigations on foam concrete’s mechanistic behavior and energy absorption properties have been published. This study examines the effects of adding fly ash (sand replacement) and polypropylene fibers to foam concrete with design densities of 1,000 and 1,500 kg/m3 on fresh state features (stability and consistency), mechanical properties, and energy absorption capacities. The consistency of foam concrete increases with the addition of foam and fly ash, but the inclusion of fibers has a significant impact. Though the addition of fibers reduced the compressive strength of foam concrete, the bonding of fibers with the matrix is strengthened in fly ash–based mixes, resulting in increased strength, showing the synergistic effect. An improvised low-velocity drop-weight impact test is carried out on foam concrete target slabs produced with various mix compositions to investigate the impact mitigation properties of foam concrete under impact loading. The energy absorption capacity of different mixtures of foam concrete specimens is found to vary between 0.3 and 1.18 J using the conservation of energy law and assuming no energy losses. Because of the availability of sufficient bubble space for crushed debris and the better impact resistance provided by the fibers, mixes with more air and fibers displayed relatively more energy absorption. To examine the mixes based on the local area effect of impact loading, observations on both energy absorption and failure mechanism are carried out.

Effect on mechanical properties of geopolymer concrete by addition of polypropylene fibers

Geopolymer Concrete (GPC) is an innovative solution in construction industry which is manufactured to replace ordinary concrete. Ordinary concrete is considered as a major construction material around the globe, but cement involved in its production contributes about 5% of world’s total carbon dioxide emissions. GPC uses alternative materials such as Fly Ash (FLA), GGBS as a replacement for cement. These materials are waste by-products of thermal and coal industries and using those materials results in reduction of overall carbon footprint. However, research shows that overall embodied energy generated by GPC is greater than traditional concrete due to extensive use of elevated curing methodology. Alkaline Binder Solutions are used as a major binder material in the process. The research incorporated addition of Polypropylene Fibers (PF) into GPC because of its high tensile capacity and crack resistance ability. Further, the research investigated mechanical properties of GPC such as Compressive Strength (CS) and Flexural Strength (FS) through varying proportions of PF from 0 to 5%, by weight respectively. Simultaneously, the research also focused on physical properties of GPC like density. CS and FS were tested conforming to the requirements of IS: 516. Moreover, a Compression Testing Machine and an Automatic Flexural Testing Machine having respective capacities of 3000kN and 300kN were used for testing CS and FS. The research findings show the addition of fibers increases FS by 49% in M6 mix which contained 5% of polypropylene fibers. However, the CS of GPC was affected negatively by the addition of PF for M6 mix, it reduced to 46% in comparison to Mix M1 with 0% fibers. Physical properties of concrete such as density also got negatively affected by the inclusion of PF. At the end of the research, Mix M3 which contained 2% PF was found more reliable than other mix proportions.

Influence of various admixtures on energy absorption characteristics of foam concrete measured using one dimensional strain analysis test

Foam concrete (FC) (a light weight cellular concrete) has recently clutched the interest of military engineering due to its special attributes such as cushioning behavior and energy absorption. However, only a very few investigations on the mechanical performance of FC and its energy absorption characteristics are reported in the literature. This study examines the effects of the addition of polypropylene fibres, fly ash (as filler replacement), and silica fume (as binder replacement) on fresh state features (stability and consistency), mechanical properties, and energy absorption characteristics. The individual and combination effects of various admixtures are studied experimentally. Hingot surfactant was used to produce FC mixes of target density 1000 kg/m3 with water to solid ratio of 0.3. Comparative analysis of various mixes showed that the fiber-reinforced fly ash mix showed the highest mechanical strength due to the bonding of fibres with the matrix, thus demonstrating synergistic behavior. Further, one-dimensional compression strain testing methodology was employed to study the energy absorption characteristics of FC. Experimental outcomes showed that the energy absorption values depend on two important components which are resistance against plastic yield, referred to as ductility, and resistance against damage referred to as the strength of the material. The incorporation of fibres enhanced the ductility of the specimen by acting as a toughening agent, whereas fly ash substitution contributed to enhancement of strength of the specimen due to pozzolanic and filler effects. Hence the combination mix with FA and PP (CMFP) showed significant improvement of 34.6% in energy absorption when compared to control mix.

Study on flexural behaviour of polypropylene fiber reinforced fly ash concrete beam

The present studies conducted on the use of polypropylene that possess high crystalline, low solidity (0.9 gm/cc), high toughness and outstanding towards chemicals and microorganisms. Polypropylene is widely used in various industrial applications such as industrial riggings, nonwovens, furnishing products, packaging things, etc. Experiments are carried out for M-30 concrete with addition of polypropylene fibers. In addition to this the cement content is interchanged by fly ash. Concrete cylinders and cubes were casted and tested for 7 days and 14 days and the test results are analyzed. The 0.4% of polypropylene fiber addition along with the 30% replacement of cement content with fly ash showed the compressive strength and split tensile strength increasing from initial stages when compared to the conservative concrete. But attained 30.22% and 46.40% for 7 days and 14 days compression test respectively. Beam of size 1 m × 0.15 m × 0.2 m is tested for flexural strength. Fibers added to a definite % of the concrete develop the strain rate as well as crash resistance and flexure power.

STRENGTH CHARACTERISTICS OF CONCRETE MADE WITH RECYCLED CONCRETE AGGREGATE (RCA), MICRO-SILICA AND POLYPROPYLENE FIBRE

Recycled concrete aggregate has been widely researched to be capable of replacing natural coarse aggregate in concrete, however, with some inadequacies in its concrete’s ability to attain the same feat in mechanical properties as normal concrete. This research work attempts to improve the strength characteristics of concrete containing recycled coarse aggregate with the addition of admixtures (Micro-Silica and Superplasticizer) and Polypropylene fibre. Results showed that admixtures significantly improved the workability and mechanical properties of CRCA at all RCA replacement levels. Addition of PPF had significant effect on the flexural and splitting tensile strengths of CRCA, but not much impact on the compressive strength.

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.

Dynamic compressive properties of new metallic hollow sphere concrete composites

The dynamic properties of new metallic hollow sphere concrete composites were investigated experimentally. Metallic hollow spheres (MHSs) at volume fractions of 10 %, 20 % and 30 % were embedded into a concrete matrix to form metallic hollow sphere concrete composites (MHSCCs) under normal temperature conditions. Dynamic compression tests using a split Hopkinson pressure bar were conducted at strain rates in the 15 s−1 ∼ 80 s−1 range on the specimens after 28 d of curing. The conditions of the concrete matrix, with and without polypropylene fibres, were tested for comparison. The failure modes, stress–strain curves, dynamic strengths, and energy absorption capacities were analysed. The results indicated that the damage degree increased with increasing MHS content and strain rate. The composites were more sensitive than plain concrete to the strain rate. Adding a certain amount of MHSs into the concrete matrix improved the dynamic compressive strength and the overall energy absorption by up to 25.4 % and 317 %, respectively, at a strain rate of approximately 70 s−1. The addition of polypropylene fibre further improved the dynamic properties of the composites due to the bridging effect of fibres; however, it had a negative influence on the dynamic increase factor.

Study on properties of SCC mixed with mineral admixtures and fibres subjected to elevated temperature

The concrete is expected to have features like high fluidity, self-compact ability, high strength, high durability, greater serviceability and long service life of concrete structures. rationalised and labour-saving benefits in manufacture and placement of concrete SCC is a highly designed concrete which addresses these needs. In this work the SCC samples with different percentage addition of ggbfs, fly ash and polypropylene fibres cured with Concentrated Sulphuric acid (H 2 SO 4 ) and Sodium hydroxide (NaOH) at the period of 60, 80 and 120 days and it was tested under the temperature of 200 °C and 400 °C and it was tested for the compressive strength. Comparing the results with the samples without addition of polypropylene fibres (1% and 2%) there is a marked improvement in the compressive strength.

Estimation of Stiffness of Non-Cohesive Soil in Natural State and Improved by Fiber and/or Cement Addition under Different Load Conditions

The aim of this study was to compare the stiffness of gravelly sand under various load conditions-static conditions using the CBR test and cyclic conditions using the resilient modulus test. The tests were conducted on natural soil and soil improved by the addition of polypropylene fibers and/or 1.5% cement. The impacts of the compaction and curing time of the stabilized samples were also determined. The soil was sheared during the Mr tests, even after fiber reinforcement, so the resilient modulus value for the unbound sand could not be obtained. The cement addition improved Mr, and the curing time also had an impact on this parameter. The fiber addition increased the value of the resilient modulus. The CBR value of the compacted gravelly sand was relatively high. It increased after adding 0.1% fibers in the case of the standard compacted samples. The greater fiber addition lowered the CBR value. For the modified compacted samples, each addition of fibers reduced the CBR value reduced the CBR value. The addition of cement influenced the CBR increase, which was also affected by the compaction method and the curing time. The addition of fibers to the stabilized sample improved the CBR value. The relationship Mr=f(CBR) obtained for all data sets was statistically significant but characterized by a large error of estimate.