STUDY ON THE FUNCTION OF REINFORCED RUBBER OF MODIFIED POWDERED COAL ASH

The powdered coal ash (PCA) was classified, then the ash particle (- 45μm) was modified by a surface active agent and obtained modified powder coal ash (MPCA). The character of the MPC was investigated, when it was used as a new type reinforced filler of rubber.The results show that MPCA can replace or party replace carbon black or silica as reinforced fillers of rubbers.

Experimental Study and Failure Criterion Analysis of Rubber Fibre Reinforced Concrete under Biaxial Compression-Compression

In order to examine the biaxial compression-compression properties of rubber fibre reinforced concrete(RFRC),an experimental study on RFRC under different lateral compressive stresses was carried out by considering different rubber replacement rates and polypropylene fibre contents.The failure modes and mechanical property parameters of different RFRC working conditions were obtained from the experiment to explore the effects of rubber replacement rate and polypropylene fibre content on the biaxial compression-compression properties of RFRC.The following conclusions were drawn.Under the influence of lateral compressive stress,the biaxial compression-compression failure mode gradually developed from a columnar pattern to a flaky pattern,suggesting that the incorporation of rubber and polypropylene fibres into the concrete resulted in a significant change in the development of cracks.For different rubber replacement rates and polypropylene fibre contents,the vertical compressive stress exhibited the same developing trend under the influence of lateral compressive stress.Specifically,the lateral compressive stress imposed the minimum effect on the vertical compressive stress when the rubber replacement rate and polypropylene fibre content were 20%and 0.4%,respectively,and imposed the maximum effect when the rubber replacement rate and polypropylene fibre content were 20%and 0%,respectively.With the increase of rubber replacement rate,the vertical peak stress was significantly reduced,which implies that an appropriate amount of polypropylene fibres can increase the vertical peak stress to a certain extent.Then,the biaxial compression-compression mechanism of RFRC was analysed from the microscopic level by using scanning electron microscope(SEM).Meanwhile,based on Kupfer’s biaxial compression-compression failure criterion and the octahedral stress space,a biaxial compression-compression failure criterion for RFRC was proposed,which was proven to have good applicability.The research results of this study provide important theoretical basis for the engineering application and development of RFRC.

Mechanical Response of Steel Wire Wound Reinforced Rubber Flexible Pipe under Internal Pressure

Steel wire wound reinforced flexible pipe in this study mainly consists of multiple anisotropic steel wire wound reinforcement layers and multiple isotropic rubber layers.Based on 3D anisotropic elastic theory,the analytic solutions of stresses and elastic deformations of steel wire wound reinforced rubber flexible pipe under internal pressure are presented.As the adjacent reinforcement layers with wound angle have different radii,the single reinforcement layer shows the effect of tensile-shear coupling.Moreover,the static loading test results of steel wire wound reinforced rubber flexible pipe under internal pressure are basically coincided with the calculated values by present method.

Surface Modification of Rice Husk Ash by Ethanol-assisted Milling to Reinforce the Properties of Natural Rubber/Butadiene Rubber Composites

Rice husk ash(RHA),obtained by pyrolysis of rice husks,can be used as a potential reinforcing filler for rubber composites.In this work,ball milling in ethanol(ethanol-assisted milling)was used to hydroxylate the surface of RHA,promoting the graft modification of bis-(γ-triethoxysilylpropyl)-tetrasulfide(Si69).The obtained modified RHA(RHA-EM-Si69)was filled into the natural rubber/butadiene rubber(NR/BR)composites,and the filler-rubber interactions were enhanced.In consequence,RHA-EM-Si69 filled NR/BR composites showed overall improvement in the mechanical properties compared with RHA filled NR/BR composites.The tear strength increased from 13.37 kN/m to 34.71 kN/m,and the tensile strength increased from 1.84 MPa to 7.75 MPa.Carbon black(N774)was also used for comparison under the same conditions.This method provides a potential for promoting the value of RHA in rubber industry.