Papers by Keyword: Polypropylene Fiber Reinforced Concrete

Abstract: The long-term durability of concrete hydraulic structures can be improved by controlling their rate of water absorption and linear shrinkage. Incorporation of fibers in concrete composites has the potential to improve these properties of concrete. Artificial fibers are commonly used in concrete due to its durable nature for long serviceable life. So, the overall aim of this research program is to study the effectiveness of artificial fibers for improvement of long-term durability of concrete hydraulic structures. To start with, polypropylene fibers are considered. The polypropylene fibers (PPF) have the unique properties of chemically inertness and low cost raw materials. The pilot study presents the experimental evaluation of water absorption and linear shrinkage of polypropylene fiber reinforced concrete (PPFRC) in comparison to that of plain concrete (PC). The mix design proportion of 1:3:1.5:0.7 (cement:sand:aggregates:water) is used in preparation of PC and PPFRC. For PPFRC, the fiber length of 50 mm and content of 5% by mass of cement are added. All tests are performed as per ASTM standard. Discussions on the considered properties of PC and PPFRC are made. As per expected outcomes PPFRC showed less water absorption and less linear shrinkage as compared to that of PC. Because of this possible attribute, the PPFRC can be used in hydraulic structures.

Abstract: concrete materials with low tensile strength, easy to crack, and the brittleness of the shortcomings in the polypropylene fiber concrete can improve performance. The compressive strength and flexural strength of the mechanical properties of polypropylene fiber reinforced concrete pilot study shows that the fiber content and curing age a great influence on the mechanical properties of polypropylene fiber reinforced concrete, the polypropylene fibers affordable dosage take1.5 percent is appropriate.

Abstract: Through a series of laboratory experiments, we find that: Polypropylene fiber mesh, which is added to the concrete, can improve the performance of the road. But the use of polypropylene fiber mesh is not the higher the better. The recommended content is 0.9 Kg/m3.

Abstract: An analytical model for compressive stress-strain curve of polypropylene fiber reinforced concrete (PPFRC) was proposed. The polypropylene fiber used was 60-mm long twisted fiber with aspect ratio of 120. The fiber was added in three volume fractions 0.2%, 0.4% and 0.6%. Tow concrete mixtures with varying water-cement ratio were used. The accuracy of the proposed model was evaluated by comparing the area under stress-strain curves for experimental and analytical model. The results showed good agreement between the experimental and analytical curves. In addition; empirical equations were proposed to quantify the effect of polypropylene fiber on compressive strength, strain at peak stress, and toughness of concrete in terms of fiber volume fraction.

Abstract: The effect of adding polypropylene fibers; with different shapes and volume fractions; on the compressive strength, modulus of rupture, load-deflection curve and flexural toughness (equivalent flexural strength ratio) of concrete was investigated. Crimped and twisted polypropylene fibers were used with 0.0%, 0.2%, 0.4% and 0.6% volume fractions. It was found that the compressive strength, flexural strength and the equivalent flexural strength ratio of concrete increased about 11%, 25% and 40% respectively by adding 0.6% volume fraction of twisted polypropylene fiber. In addition; it was found that the contribution of polypropylene fiber to the flexural strength and flexural toughness was more effective when twisted polypropylene fiber was added comparing to crimped polypropylene fibers. The experimental results were used in numerical example using FAARFIELD program to explore the airfield pavement thickness reduction resulted from polypropylene fiber incorporation.

Abstract: In order to meet the running needs of the first-stage construction in the middle line of South-to-North Water Transfer Project, the canal lining of both sides of Yellow River Tunnels Project need the use of mechanized equipment construction in order to improve the quality and efficiency of lining construction, there is a need to study the feasibility of the use of polypropylene fiber concrete instead of reinforced concrete in canal lining. This paper analyzes the effect of polypropylene fiber on concrete shrinkage and crack resistance. The results show that all three polypropylene fibers have properties of a low density and high elongation, the dispersivity test results show that dispersivity is better when stirring fiber A after a certain period of time. After the incorporation of polypropylene fibers, the concrete splitting tensile strength is significantly increased, altogether with ultimate tensile value and frost resistance. The incorporation of polypropylene fibers increases the tensile strength of concrete and improve the toughness of it. Compared with standard concrete, the early shrinkage of polypropylene fiber concrete is significantly lower, the incorporation of polypropylene fibers can take the place of steel mesh in concrete cracking, especially in the early control of concrete cracks, it can effectively prevent and suppress the cracks formation and development. This paper recommends the concrete proportioning parameters meeting the requirements of canal lining concrete technology and construction.

Abstract: The wet sprayed concrete technique has good virtue of improving the working condition within the tunnel, fewer reflective concrete loss and higher sprayed concrete quality. The concrete mixed with polypropylene fiber could improve the concrete inner structure, the flexural strength, tensile strength and anti-penetrating ability. The application of the wet sprayed polypropylene fiber reinforced concrete in the construction of tunnel lining structure could improve the stability of tunnel rock mass. The nonlinear finite element analysis is performed on rock mass stability of the railway tunnel lining structure and the rock mass stability is analyzed both for the un-lining tunnel and the lining tunnel. The computation result shows that the rock mass plasticity zone distribution with the lining structure is fewer than that without lining structure. To measure the deformation behavior, tunnel deformation measurement sensors are installed in the railway tunnel transverse section. The measured railway tunnel deformation result also shows that the lining structure deforms little and the rockmass is in stable state.

Abstract: The fracture toughness and the fracture energy are obtained on the notched beams in three-point bending according to the RILEM draft recommendation. An experiment is designed to obtain the law on the alteration of the PPFRC’s (Polypropylene Fiber Reinforced Concrete) fatigue life and fatigue strength caused by the fibers. S-lgN curve is plotted according to the experimental data and fatigue is obtained through the Linear Regression. Theoretical analysis of the PPFRC’s bending fatigue characteristic is carried out. The fiber’s influence on the PPFRC’s fatigue behavior is stated and the fiber reinforcement mechanism is discussed. The result shows that the fiber can improve the PPFRC’s fatigue life and fatigue strength. The composition and development of the fatigue strain under the cyclic load are analyzed using experimental data. The law of the fatigue damage accumulation and evolution under cyclic load is studied. A fatigue damage mode, which can be used to predict the fatigue life of the PPFRC, is established.