Amount Of Polypropylene Fibers Research Articles

Ultrasonic Test Analysis of Impact Damage of Polypropylene Fiber Mortar

The method recommended by ACI Committee 544 was used in this paper. Drop hammer impact tests based on mortar specimens with different contents of polypropylene fiber were carried out. The Ultrasonic test is done before and after impacting. Under different drop hammer impact times, polypropylene fiber mortar specimens' damage degree was evaluate based on ultrasonic velocity. The results show that the hammering number corresponding to the impact fracture of polypropylene fiber mortar is more than ordinary mortar. The ultrasonic velocity of all specimens decreased gradually during the process of hammering, but adding the right amount of polypropylene fibers can effectively slow down the rate of wave speed decline.

Experiment and Research on Mechanic Behavior of Concrete with Different Addition Amounts of Polypropylene Fibers

The effect of the different addition amounts of polypropylene fibers on the basic mechanical properties of concrete were investigated in this paper. The results show that the flexural tensile strength of concrete changed slightly after adding low-dosage polypropylene fiber(0.04%～0.16%); Axial compressive strength and flexural tension modulus decreased, limiting flexural strain increased gradually with the amounts of fibers rising.

Research on Impact Damage of Polypropylene Fiber Mortar Based on Axial Compressive Strength

The method recommended by ACI Committee 544 was used in this paper. Drop hammer impact tests based on mortar specimens with different contents of polypropylene fiber were carried out. The compressive strength test is done before and after impacting. Under different drop hammer impact time, polypropylene fiber mortar specimens’ damage degree was evaluate based on compressive strength. The results show that the hammering number corresponding to the impact fracture of polypropylene fiber mortar is more than ordinary mortar that without fiber. The axial compressive strength of all specimens decreased gradually during the process of hammering, but adding the right amount of polypropylene fibers can effectively slow down the rate of strength reduction.

PREDICTION OF ELASTIC MODULUS OF POLYPROPYLENE FIBER CONTAINING CONCRETE BY FUZZY LOGIC

In this study, the amount of polypropylene fiber was investigated that effect to physical (unit weight, air content) and mechanical (compressive strength and modulus of elasticity) properties of concrete. The different amounts of polypropylene fiber (0, 300, 600, 900, 1200 gr/m3) to prepared mixtures in three different cement dosage (350, 400 and 450 kg/m³) were added. According to experimental results, unit weight, compressive strength and modulus of elasticity decreases while the air content increases depend on the amount of fiber. Estimation model of the modulus of elasticity from the cement dosage, fiber content and air content is developed by using fuzzy logic. Also, It was investigated that relationships between experimental results with model results or analytical equations that proposed by the standards. As a result, proposed approaches by standards have been inadequate in determining modules of elasticity of the fiber containing concrete, the best results were obtained from fuzzy logic model (R2 = 0,988). It should be developed the new analytic equations for fiber containing concrete and fuzzy logic is used successfully to predict the properties of fiber concrete are usable.

Pore structure and chloride permeability of concrete containing nano-particles for pavement

Pore structure and chloride permeability of concrete containing nano-particles (TiO 2 and SiO 2) for pavement are experimentally studied and compared with that of plain concrete, concrete containing polypropylene (PP) fibers and concrete containing both nano-TiO 2 and PP fibers. The test results indicate that the addition of nano-particles refines the pore structure of concrete and enhances the resistance to chloride penetration of concrete. The refined extent of pore structure and the enhanced extent of the resistance to chloride penetration of concrete are increased with the decreasing content of nano-particles. The pore structure and the resistance to chloride penetration of concrete containing nano-TiO 2 are superior to that of concrete containing the same amount of nano-SiO 2. However, for the concrete containing PP fibers, the pore structure is coarsened and the resistance to chloride penetration is reduced. The larger the content of PP fibers, the coarser the pore structure of concrete, and the lower the resistance to chloride penetration. For the concrete containing both nano-TiO 2 and PP fibers, the pore structure is coarser and the resistance to chloride penetration is lower than that of concrete containing the same amount of PP fibers only. A hyperbolic relationship between chloride permeability and compressive strength of concrete is exhibited. There is an obvious linear relationship between chloride permeability and pore structure of concrete.

A testing method for measuring plastic shrinkage in polypropylene fibre reinforced mortars

The use of concretes reinforced with a low volume of polypropylene fibres added as secondary reinforcement, mainly to control cracking due to plastic shrinkage at early stages is of recent interest. In this paper, a method for measuring plastic shrinkage of mortars is proposed. The influence of the water/cement ratio, cement/sand ratio and amount of polypropylene fibres on the plastic shrinkage of mortars is also studied. The method presented in this paper gives information about the quality of the material studied in terms of plastic shrinkage and potential cracking.

Model for predicting plastic shrinkage of polypropylene reinforced mortars

There is increasing interest in the use of concretes reinforced with a low volume of polypropylene fibres added as secondary reinforcement, mainly to control cracking due to plastic shrinkage at an early age. This paper discusses the influence of water-cement ratio, cement-sand ratio and amount of polypropylene fibres in the plastic shrinkage of mortars. A prediction method, based on a factorial design of experiments, is also proposed.