Blends of nitrile rubber and reclaimed rubber containing different levels of a
coupling agent, Si 69 (bis(3- triethoxysilyl propyl)(tetrasulphide) were prepared
and the cure characteristic's and mechanical properties were studied. Optimum
loading of Si-69 was found to be a function of blend ratio. 3 phi- of Si 69 in a
70:30. Blend was found to be the optimum combination with respect to the
mechanical properties. The rate and state of cure were also affected bv the
conp/ing agent. Tensile strength, tear strength and abrasion resistance were
improved in the presence of coupling agent. While the state of cure improved,
the cure rate and scorch time decreased with increasing silane content. Ageing
studies showed that the blends containing the coupling agent were inferior to
the unmodified blends.
Job, Thomas; Ananth, Ramaswamy(American Society of Civil Engineers, May , 2007)
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Abstract:
This paper presents the results from an experimental program and an analytical assessment of the influence of addition of
fibers on mechanical properties of concrete. Models derived based on the regression analysis of 60 test data for various mechanical
properties of steel fiber-reinforced concrete have been presented. The various strength properties studied are cube and cylinder compressive
strength, split tensile strength, modulus of rupture and postcracking performance, modulus of elasticity, Poisson’s ratio, and strain
corresponding to peak compressive stress. The variables considered are grade of concrete, namely, normal strength 35 MPa , moderately
high strength 65 MPa , and high-strength concrete 85 MPa , and the volume fraction of the fiber Vf =0.0, 0.5, 1.0, and 1.5% . The
strength of steel fiber-reinforced concrete predicted using the proposed models have been compared with the test data from the present
study and with various other test data reported in the literature. The proposed model predicted the test data quite accurately. The study
indicates that the fiber matrix interaction contributes significantly to enhancement of mechanical properties caused by the introduction of
fibers, which is at variance with both existing models and formulations based on the law of mixtures
Description:
Journal of
Materials in Civil Engineering, Vol. 19, No. 5, May 1, 2007.
Mechanical properties and thermal degradation characteristics of natural rubber compounds
captaining coconut oil were compared with that of a control compound containing naphthenic oil.
Cure time was marginally lower in the case of coconut oil mixes, probably due to the presence of
free fatty acids. Tensile strength , tear strength, resilience and abrasion resistance were better than
the naphthenic oil-based compounds . Compression set and hardness were marginally inferior
The coconut oil mixes had a crosslink density comparable to that of the reference compound.
Thermal studies showed that the temperature of initiation of degradation was increased by 10°C
and the temperature at which the peak rate of degradation occured was increased by 7°C. The
peak rate of degradation was compa rable to the control compound.