Strength Retention Capacity Research Articles

Evaluation of mechanical properties of carbon HDPE composites

Use of carbon in its nano/micro dimension state holds a great potential to evolve unique properties of carbon-based polymer composites. In this study, activated carbon and carbon black reinforced composites have been tested for their strength retention capacity and other mechanical properties. Homogeneous blending of naturally available micro dimension carbon black along with high density polyethylene polymer matrix was achieved to produce a composite as a replacement to the expensive nanoscale carbon composites. High density polyethylene is a wonder material and is known for its large strength to density ratio. These high-density polyethylene/ carbon composites find applications in diversified areas like food racks, water pipes, insulation, vehicle fuel tanks, protective helmets, etc. The activated carbon and carbon black reinforced polymer composite samples were fabricated using varying filler loadings and were further subjected to mechanical testing. The major property elevation of strength and durability was observed after loading 2 wt% carbon black in the polymer composite. Henceforth, the obtained carbon black loaded polymer composite showed better mechanical behavior compared to its pristine as well as activated carbon loaded configuration.

Seismic performance of steel plate reinforced high toughness concrete coupling beams with different steel plate ratios

Embedded steel plate reinforced concrete (PRC) coupling beams are newly introduced into the family of coupling beams to improve the seismic behavior of reinforced concrete (RC) coupling beams. However, the brittle crush and spalling of concrete in these composite members noticeably reduce their deformation performance and energy-dissipating capacity which largely deteriorate the efficiency of this combination. Considering this noteworthy shortcoming, in this paper the authors propose a novel type of composite coupling beams, which is entitled steel plate reinforced high toughness concrete (PRHTC) coupling beam. This novel member replaces the conventional reinforced concrete with the high toughness concrete (HTC) which is a sort of pseudo strain-hardening cementitious composites exhibiting quasi-ductile behaviors. This study mainly investigates the seismic performance of PRHTC deep coupling beams (span-to-depth ratio, l/h = 1.5) with various steel plate reinforcement ratios. The test results indicate that the PRHTC coupling beams exhibit a ductile flexural failure mechanism with excellent energy dissipation capability. The high toughness concrete in this composite member displays multiple cracking pattern and maintains desirable integrity. All specimens attained high-level ductility factors exceeding 5.5, survived large rotations ranging from 0.064 to 0.078 rad, manifested superior stiffness retention capacity and strength retention capacity. The steel plate ratio ranging from 4.31% to 6.47% is proven to be appropriate and effective for maintaining high ductility and rotation deformability of the PRHTC coupling beams in this paper.

Effect of addition of Cr2O3 on the properties of reaction sintered MgO–Al2O3 spinels

Abstract Effect of addition of Cr2O3 up to 4 wt.% was studied on three different spinel compositions with MgO:Al2O3 molar ratios 2:1, 1:1 and 1:2. Attritor mill was used to reduce the particle size of the starting materials and a single stage sintering technique was employed in the temperature range of 1550–1650 °C for all the compositions. Final sintered products were then characterised in terms of densification and shrinkage studies, phase analysis, strength evaluation both at the ambient temperature and at 1300 °C, strength retention capacity after different cycles of thermal shock at 1000 °C, quantitative elemental analysis and microstructural studies.