Performance Of Polypropylene Fiber Research Articles

RETRACTED: Biaxial mechanical behaviour of polypropylene fibres reinforced self-compacting concrete

This study intends to assess the biaxial performance of polypropylene fibres (PPF) reinforced self-compacting concrete (SCC) under various stress levels. For this purpose, PPF were added at five contents: 0%, 0.5%, 1%, 1.5% and 2%, and the three zones of failure were measured including compression-compression, tension-tension and compression-tension. Therefore, lateral compressive and tensile stresses were applied at four different levels. Finally, new models were developed to predict the structural performance of PPF reinforced SCC under different stress conditions and for various PPF contents. According to the results, in both SCC and PPF reinforced SCC under biaxial compression, cracks were stopped when the minimum principal stress (f2) was applied. Therefore, f2 could avoid the tensile stress creation resulting from the maximum principal stress (f1). Therefore, in a biaxial and uniaxial stress state, failure occurred in shear and tensile modes, respectively. In addition, PPF had a substantial influence on the angle of cracking (ranging from 15° to 45°).

Mechanical performance of concrete reinforced with polypropylene fibers (PPFs)

Fibers are one of the most prevalent methods to enhance the tensile capacity of concrete. Most researchers focus on steel fiber reinforced concrete which is costly and easily corroded. This study aims to examine the performance of polypropylene fiber reinforced concrete through different tests. PPFs were added into concrete blends in a percentage of 1.0%, 2.0%, 3.0%, and 4.0% by weight of cement to offset its objectionable brittle nature and improve its tensile capacity. The fresh property was evaluated through slump cone test and while mechanical strength was evaluated through compressive strength, split tensile strength flexure strength, and flexure cracking behaviors after 7-, 14-, and 28-days curing. Results indicate that slump decrease with the addition of PPFs while fresh density increase up to 2.0% in addition to PPFs and then decreases. Similarly, strength (compressive strength; split tensile strength, and flexure strength) was increased up to 2.0% addition of PPFs and then decrease gradually. It also suggests that Ductility; first crack load, maximum crack width, and load-deflection inter-relations were considerably improved due to incorporations of PPFs.

An Experimental Study on the Compressive Dynamic Performance of Polypropylene Fiber Reinforced Concrete for Retaining Structure under Automobile Collision Magnitude

In order to examine the compressive dynamic performance of polypropylene fiber reinforced concrete to be used for the retaining structure under the automobile collision magnitude, an experimental study was carried out by using hydraulic servo on concrete specimens with 4 different polypropylene fiber contents under 6 loading strain rates. The failure modes and stress‐strain curves of concrete under different loading conditions were obtained. Then, by comparatively analyzing the mechanical characteristic parameters of polypropylene fiber reinforced concrete under different loading conditions, the following conclusions are drawn: with the increase of the polypropylene fiber content, the integrity of concrete upon compressive failure is gradually improved. When the polypropylene fiber content is relatively high, the static and dynamic failure modes are basically similar. With the increase of the loading strain rate, the peak compressive stress and elastic modulus of the polypropylene fiber reinforced concrete gradually increase. The increase in the polypropylene fiber content gradually intensifies the effect of loading strain rate on the peak compressive stress dynamic improvement coefficient. The peak strain of polypropylene fiber reinforced concrete is gradually increased with the increase of polypropylene fiber content, while the effect of the loading strain rate on the peak strain shows an obvious discreteness characteristic. Meanwhile, we proposed a relationship equation for describing the peak compressive stress dynamic improvement coefficient based on the coupling effect of the polypropylene fiber content and loading strain rate and further discussed the underlying stress mechanism in detail. Our research findings are of important research significance for the application and promotion of polypropylene fiber reinforced concrete in the engineering practice of retaining structures.

Effects of Temperature and Stress on Creep Behavior of PP and Hybrid Fiber Reinforced Reactive Powder Concrete

Reactive powder concrete (RPC) is an advanced cementitious material with ultra-high strength, remarkable durability and excellent toughness. However, temperature dependent creep is a major concern as very little work has been reported in the literature. Therefore, systematic investigations are still missing in state of the art. This paper focuses on the impact of Polypropylene (PP) and hybrid (steel and PP) fibers on creep behavior of RPC at elevated temperature. Temperature-dependent creep is further characterized into free thermal strain (FTS), short-term creep (STC) and transient strain (TS), based on different thermo-mechanical regimes. Varying heating and loading schemes were considered such as steady-state and transient thermo-mechanical conditions. The target temperatures considered for steady-state thermal conditions and transient case are 120, 300, 500, 700 and 900 °C. Compressive strength was considered up to 60% load ratio of ambient and temperature dependency. The result shows that STC increases with increasing stress level and higher target temperature. The increase in STC becomes obvious above the transition stage of quartz aggregate. Furthermore, HRPC have significantly higher STC than PRPC and other traditional types of concretes. The evolution of FTS and TS was quite slow below 250 °C. However, at high temperature significant increase in FTS and TS were observed. Furthermore, increasing stress level and the addition of steel fibers results in high TS. Overall, the performance of PP fiber was better than the hybrid fibers on the creep behaviour of RPC. Finally, constitutive relationships were proposed for FTS, STC and TS, which will be used as input data in numerical models of fire resistance calculations.

Dynamic behaviour of saturated sandy soil reinforced with non-woven polypropylene fibre

This research presents results of shaking table tests which were carried out on the soil reinforcement with randomly distributed synthetic fibres. The main scope of the study is to investigate the reliability and performance of polypropylene fibres in improving liquefaction resistance of loose sand prone to liquefaction. Dynamic properties of reinforced sand such as shear modulus and damping ratio were obtained, analysed and compared to those of unreinforced sand. The results indicated that shear modulus and damping ratio are increased by adding fibrous materials as a reinforcement to the host sandy soil. However, no meaningful improvement was achieved by reducing pore water generated during shaking. Outcomes also demonstrated that liquefaction-induced settlement is slightly higher in reinforced soil when compared to unreinforced soil.

Study on the Dynamic Performance of Polypropylene Fiber Reinforced Concrete

The dynamic performance of polypropylene fiber reinforced concrete is studied with the SHPB experiment. The relationship of the strain-stress curves are all obtained in the experiment. The crack characteristics of polypropylene reinforced concrete and plain concrete are also investigated. Analyzed the relation between the character on the crack surface of concrete and material properties and the impact pressure. Also the multi-fractal characteristics are given on the crack surface of concrete. The crack distributions of plain concrete and polypropylene concrete are investigated. The crack resistance effects of polypropylene fiber are analyzed from the degree of closeness and uniformity.

Earthquake-Resistant Performance of Polypropylene Fiber Reinforced Concrete Beam

The cyclic behavior of polypropylene fiber reinforced, plain concrete beams was studied in this research work. The reinforcement and volume ratio of polypropylene fiber were kept constant for all the beams. The beams were same dimensions, and the beams were tested under positive cyclic loading and the results were evaluated with respect to crack strength, ductility, energy absorption capacity, and stiffness behavior. The results showed that polypropylene fiber concrete beams had only slight effect on the stiffness, cracking moment, and ultimate moment. From the test results it was observed that polypropylene fibers were effective in reducing the crack width and crack propagation. Furthermore, it was observed that introduction of polypropylene fiber significantly improves the cracking behavior in terms of a formation of large number of finer cracks. Combining polypropylene fibers and reinforcement improved the behavior of reinforced concrete beams and changed its failure mode. Addition of polypropylene fiber to RCC imported ductility to structural members which is essential for seismic force-resisting structure.

Study on Freeze-Thaw Performance of Polypropylene Fiber Reinforced Cement-Stabilized Aggregate

Study on Freeze-Thaw Performance of Polypropylene Fiber Reinforced Cement-Stabilized Aggregate

Study on Freeze-Thaw Performance of Polypropylene Fiber Reinforced Cement-Stabilized Aggregate

In this paper, the authors study the anti-freeze-thaw performance of a new type of semi-rigid base material named polypropylene fiber reinforced cement-stabilized aggregate, and freeze-thaw mass loss rate, freeze-thaw compressive strength, freeze-thaw splitting strength are used to evaluate the effect of polypropylene fiber on the anti-freeze-thaw performance, and the relationship of polypropylene fiber content, polypropylene fiber length with the anti-freeze-thaw performance are analyzed. The test after 10 freeze-thaw cycle shows that the mix of polypropylene fiber increase the freeze-thaw compressive strength and freeze-thaw splitting strength, and decrease the mass loss rate greatly. At the same time, the paper also determine the reasonable fiber content and fiber length, under this mix proportion, the mass loss rate reduce by 80%, the freeze-thaw compressive strength increase more than 12.1% and freeze-thaw splitting strength increase more than 13.4%. This research has laid an important foundation for the follow-up research and practice.

Research on Anti-Cracking Performance of Polypropylene Fiber Reinforced Cement Mortar

Adding suitable quantity of polypropylene fiber is very effective for controlling plastic crack of cement mortar. During the experience stage, adding quantity of polypropylene fiber is 1.5 kg/m3, and crack rate of mortar is only 7.7%. Theoretical analysis is made for plastic crack mechanism of cement mortar, the results indicate that adding polypropylene fiber improves critical stress of crack expansion in mortar and notably reduces crack of cement mortar.

Study on the Toughness Performance of Polypropylene Fiber and SBR Polymer Latex Modified Cement Mortar

In this paper, polypropylene fiber and SBR polymer latex are added into cement mortar to improve the toughness. Using two flexural toughness test methods of ASTM-C1018 and JSCE-SF4, the ratio of compressive strength to flexural strength (σC/σF for short) and flexural toughness index are used to evaluate the toughness of the cement mortar. The experimental results show that, comparing to the control cement mortar sample, when the SBR polymer mass percent of 20% and the polypropylene fiber volume percent of 1.0%, the σC/σF is 2.17, reduced by 59.2%, the ASTM toughness index I5, I10, I30 is 2.86, 2.95, 3.16 respectively, increased by 63.4%, 58.6%, 68.1% respectively, the JCI toughness index is 13.1, increased by 258%. Based on the SEM, adding SBR-polymer into cement mortar can form the polymer transition layer between the interfaces of polypropylene fibers and cement matrix, from XRD test, SBR polymer latex has no significant influence on the cement hydration after 7d curing. This research provides some useful references for the application of this new material.

Performance of Polypropylene Fiber and Rubber Powder Improved High Strength Concrete

Based on high strength concrete (HSC), the improved HSC concrete was produced by adding different contents of fine grain rubber particles and polypropylene fibers. The grain size of the rubber particle is 420 m and the rubber content is 1%, 2%, and 3% of the mass of cementitious material respectively. The volume fraction of polypropylene fiber is 0.1%.The performance of HSC, rubber particle improved high strength concrete (RHSC), polypropylene fiber improved high strength concrete (PHSC) and polypropylene fiber hybrid rubber particle improved high strength concrete (PRHSC) before and after high temperature are studied. The investigation methods used are the external surface inspection, weight loss and residual strength testing. The experimental results show that rubber particles can improve the workability of HSC and PHSC under normal temperature. Polypropylene fiber can significantly improve the spalling failure resistance property of HSC and RHSC.