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Performance of Polypropylene Fiber Reinforced Concrete Containing Slag

Author: ZhangHuiLi
Tutor: CaiHuanJie
School: Northwest University of Science and Technology
Course: Agricultural Soil and Water Engineering
Keywords: High performance concrete Polypropylene fibers The mill fine-grained blast furnace slag Performance Strengthening mechanism
CLC: TU528.572
Type: PhD thesis
Year: 2010
Downloads: 387
Quote: 0
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Abstract

Polypropylene fibers as a reinforcement material for concrete can improve the brittleness of concrete, concrete tensile properties. Grinding fine blast furnace slag as an industrial waste instead of part of the cement is mixed with polypropylene fiber reinforced concrete, and be able to take full advantage of the solid waste, saving cement, reduce the price of polypropylene fiber reinforced concrete. Polycarboxylate superplasticizer as an environmentally efficient superplasticizer to improve the compatibility of the binder. In this paper, a number of theoretical and technical issues slag polypropylene fiber concrete existence to incorporation of highly dispersed polypropylene fiber concrete and blast furnace slag grinding fine-grained as the object of study, using a combination of laboratory experiments and theoretical analysis, the focus of research performance of the fresh concrete, hardened concrete ultrasonic pulse rate, basic mechanical properties and flexural fatigue performance, draw the following conclusions: of polycarboxylate superplasticizer polypropylene fibers and slag compatibility is better, can significantly reduce slump to loss; polypropylene fiber the collapsed drop-degree barrel time, effectively inhibit the concrete free shrinkage, increase the gas content, reducing the concrete density. Slag incorporation also extend the collapsed drop-degree barrel time, reduce the concrete density, effective suppression of free shrinkage of concrete, but not significantly on the gas content; polycarboxylate superplasticizer gas content, the amount of free shrinkage and saturated surface dry density has a significant impact. Polypropylene fibers reduces the concrete compressive strength and elastic modulus, Poisson ratio; slag improves the compressive strength and modulus of elasticity; polycarboxylate superplasticizer cement better compatibility. Polypropylene fibers, slag and polycarboxylate superplasticizer composite effect is obvious. Based on the experimental data to create the relationship between the modulus of elasticity and compressive strength, adapted the slag polypropylene fiber reinforced concrete. The scanning electron microscope test analysis showed that the ratio of different concrete hydrates of different shape and performance, significantly affect the macroscopic compressive strength of the concrete. Polypropylene fiber volume content of 0.1% to 0.8% to improve the resistance of concrete splitting tensile strength, splitting tensile strength of concrete anti-incorporation of slag cement replacement rate of 35% to 65% increase, of which 0.4% polypropylene fiber and 45% of ground blast furnace slag granulation the highest anti splitting tensile strength, compared with the control group increased by 1.72 times the resistance of concrete splitting tensile strength, polypropylene fibers and slag composite effect significantly. SEM photographs reveal the strengthening mechanism from the microscopic structure. Anti-splitting tensile strength in the range of 10% to 12% of the corresponding compressive strength, compressive strength and resistance to splitting tensile strength between the 1.5075 power of relationship. Polypropylene fibers inhibit the expansion of micro-cracks, delay and inhibit the emergence and development of the macro-crack concrete flexural strength. Polypropylene fibers increase the holding charge deformation capacity, increase the concrete's ability to absorb energy, and improve the toughness of concrete. Slag and its hydrates, increase the density of the microscopic structure of the substrate to improve the flexural strength of concrete. Chemical and physical analysis, 0.1% to 0.6% polypropylene fibers and significantly lower than the 55% of the content of the slag composite effect. 0.4% of polypropylene fibers and 55% slag Admixed get the highest flexural strength and toughness index; 0.6% polypropylene fibers and 45% to obtain the Slag Complex doped with the highest residual strength factor. Cumulative flexural fatigue strength can more accurately assess the concrete flexural fatigue performance. Polypropylene fiber concrete cumulative flexural fatigue strength and fatigue life; electron microscope scan test analysis showed that the concrete structure of dense slag hydrates to improve the interface transition layer ITZ structure, beneficial to the improvement of concrete flexural fatigue performance; bending fatigue performance decreased as the stress level, stress levels and fatigue between the number of SN mathematical model can be used to predict given frequency dynamic fatigue loads slag polypropylene fiber concrete life of the project; 20Hz test the higher the frequency, the worse the bending fatigue behavior between the number of fatigue loading frequency and fatigue FN mathematical model can be used to predict the variable frequency dynamic fatigue loading under slag polypropylene fiber concrete engineering life. Ultrasonic pulse rate decreases with increasing polypropylene fiber content increases with increasing slag content the polycarboxylate superplasticizer dosage of ultrasonic pulse rate; relative error analysis results show that the establishment of ultrasonic pulse velocity prediction model is reliable, and the use of ultrasonic relationship between the rate and the compressive strength of polypropylene fiber concrete practical engineering slag can be used for non-destructive testing and intensity forecasts. The results proved that the slag polypropylene fiber concrete is a higher cost of new building materials, and has broad application prospects in hydraulic engineering and civil construction.

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CLC: > Industrial Technology > Building Science > Building Materials > Non-metallic materials > Concrete and concrete products > Reinforced Concrete > Fiber Reinforced Concrete
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