Reinforcement mechanisms

lateral restraint of the base and/or subgrade through geotextile—soil interface shear resistance 

increase in the system-hearing capacity by forcing the potential-bearing capacity failure 

The mechanisms identified for roads are equally applicable to railroads. Whereas the early use of geotextiles in railroads was primarily for separation and initially used heavy nonwoven geotextiles, it was apparent from measured improved performance that the geotextiles also tended to confine and correspondingly reduce deformation in the supporting ballast beneath load-bearing members of the track. 

Geotextiles have been used for reinforcement in roadway systems since the early 1970s, although they are best known for their application as a separator (which is always a primary function, even with reinforcement benefits). An early project in North America was the construction of a paved roadway section over a peat bog in southern Wisconsin in 1972 (Soil Testing Services, 1972). In this project, anonwoven geotextile was used to facilitate the construction of the roadway by providing improved support over a very soft subgrade. 

Much of the research on the mechanism of geotextiles has identified limits for which the reinforcement mechanisms are considered to be effective. The influence of each mechanism tends to diminish with stronger subgrade conditions and as each additional 

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In order to understand the effect of discontinuous fibres in a polymer matrix it is important to understand the reinforcing mechanism of fibres. Fibres exert their effect by restraining the deformation of the matrix as shown in Fig. 3.28. The external loading applied through the matrix is transferred to the fibres by shear at the fibre/matrix interface. The resultant stress distributions in the fibre and matrix are complex. In short fibres the tensile stress increases from zero at the ends to a value ([Pg.226]

Reinforcement of polymer matrices using various types of nanofillers is being extensively studied nowadays. The reinforcement mechanisms as well as enhancement of properties are different with different types of fillers. This field is quite green and many more developments are yet to come to enrich our science and technology in the near future. 

V.M. Litvinov and P.A.M. Steeman, EPDM-Carbon black interactions and the reinforcement mechanisms, as studied by low resolution NMR, Macromolecules, 32(25), 8476-8490, 1999. 

Considers physics and engineering topics, including reinforcement mechanisms viscoelasticity abrasion, fatigue, adhesion rheology, mixing, and processing and the effects of time, temperature, and fluids... 

Zarevics P, Seller PE (1979) Simultaneous rate-independent and rate-dependent assessment of intracranial self-stimulation evidence for the direct involvement of dopamine in brain reinforcement mechanisms. Brain Res 169 499-512. 

Sato N., Kurauchi T., Sato, S. and Kamigaito O. (1988). Reinforcing mechanism by small diameter fiber in short fiber composite. J. Composites Mater. 22, 850-873. 

The effect of polymer-filler interaction on solvent swelling and dynamic mechanical properties of the sol-gel-derived acrylic rubber (ACM)/silica, epoxi-dized natural rubber (ENR)/silica, and polyvinyl alcohol (PVA)/silica hybrid nanocomposites was described by Bandyopadhyay et al. [27]. Theoretical delineation of the reinforcing mechanism of polymer-layered silicate nanocomposites has been attempted by some authors while studying the micromechanics of the intercalated or exfoliated PNCs [28-31]. Wu et al. [32] verified the modulus reinforcement of rubber/clay nanocomposites using composite theories based on Guth, Halpin-Tsai, and the modified Halpin-Tsai equations. On introduction of a modulus reduction factor (MRF) for the platelet-like fillers, the predicted moduli were found to be closer to the experimental measurements. 

Xue, G. et al. The Reinforcement Mechanism of Polyester Fiber-Reinforced Rubber, J. Appl. Polym. Sci., submitted... 

In spite of their long history, reinforcement mechanisms and elastic properties of elastomers remain the subject of numerous experimental investigations 111 116>, but... 

Fillers serve numerous functions but common to all events is their effect brought about by increasing the viscosity of the formulation. There is the strong possibility of a vigorous attack by the operating environment on what is basically the reinforcing mechanism of the elastomer in highly loaded compounds. The function of cross links requires no elaboration. How they are created and how they subsequently perform is another story told in chapter 10. 

Very recently, Xia et al.43 reported microstructural investigations on MWCNTs which had been formed within the regular and well-aligned pores of an alumina membrane. The material was too thin (20-90 pm) to permit mechanical measurements, but different possible reinforcement mechanisms induced by the CNTs were evidenced on stressed and damaged materials,... 

In addition to the commercial rubber grades, model polymers with variable molar mass and narrow molecular weight distribution are often used for studying reinforcement mechanisms. (In Sect. 4.3 we consider a special S-SBR type with 29 vol.% vinyl and 25 vol.% styrene units Mw/Mn=l.l). 

McBride WJ, Murphy JM, Ikemoto S (1999) Localization of brain reinforcement mechanisms intracranial selfadministration and intracranial place-conditioning studies. Behav Brain Res 101. 129-152. 

Keywords elastomers, filler dispersion, interfacial adhesion, reinforcement, mechanical properties, thermal stability. 

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