The impact resistance and mechanical properties of reinforced self-compacting concrete with recycled glass fibre reinforced polymers

Variations in the mechanical properties of the glass fibre reinforced polymers were seen when exploring nano fillers such as Multi Walled Carbon Nano Tubes (MWCNTs) and graphene powders for reinforcement. GFRP composites when fabricated with increase in percentage weights of MWCNTs and graphene get better interfacial bonding with the matrix. Nano fillers improve the performance of the composites. This paper deals with the examination and experimental investigations carried out for the prediction of the enhancement of mechanical properties on GFRP reinforced with MWCNTs and graphene powders. GFRP composites were fabricated with variations in the amount of nano fillers in percentage weights of 2%, 4%, 6%, 8% and 10% wt. MWCNTs and graphene powders. The method used for reinforcement of resin with nano fillers was ultrasonication method meant for avoiding voids. A tendency for the mechanical properties to deteriorate was observed when nano fillers added were beyond certain weights of MWCNTs and graphene powders. This could be due to the agglomeration of nano fillers that change the fibre/matrix interface. Graphene nano fillers opts to be better compared to MWCNTs since the fabricated graphene reinforced glass fibre specimens have a better performance than GFRP specimens reinforced with MWCNTs.

Download Full-text

Effect of combined drink cans and steel fibers on the impact resistance and mechanical properties of concrete

JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES ◽

10.15282/jmes.14.2.2020.15.0527 ◽

2020 ◽

Vol 14 (2) ◽

pp. 6734-6742

Author(s):

A. Syamsir ◽

S. M. Mubin ◽

N. M. Nor ◽

V. Anggraini ◽

S. Nagappan ◽

...

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Compressive Strength ◽

Reinforced Concrete ◽

Impact Resistance ◽

Fiber Reinforced Concrete ◽

Steel Fibers ◽

Fiber Reinforced ◽

Indirect Tensile ◽

The Impact

This study investigated the combine effect of 0.2 % drink cans and steel fibers with volume fractions of 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% to the mechanical properties and impact resistance of concrete. Hooked-end steel fiber with 30 mm and 0.75 mm length and diameter, respectively was selected for this study. The drinks cans fiber were twisted manually in order to increase friction between fiber and concrete. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the strength performance of concrete, especially the compressive strength, flexural strength and indirect tensile strength. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the compressive strength, flexural strength and indirect tensile strength by 2.3, 7, and 2 times as compare to batch 1, respectively. Moreover, the impact resistance of fiber reinforced concrete has increase by 7 times as compared to non-fiber concretes. Moreover, the impact resistance of fiber reinforced concrete consistently gave better results as compared to non-fiber concretes. The fiber reinforced concrete turned more ductile as the dosage of fibers was increased and ductility started to decrease slightly after optimum fiber dosage was reached. It was found that concrete with combination of 2% steel and 0.2% drink cans fibers showed the highest compressive, split tensile, flexural as well as impact strength.

Download Full-text

Effect of SWCNT-Tuball Paper on the Lightning Strike Protection of CFRPs and Their Selected Mechanical Properties

Materials ◽

10.3390/ma14113140 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3140

Author(s):

Kamil Dydek ◽

Anna Boczkowska ◽

Rafał Kozera ◽

Paweł Durałek ◽

Łukasz Sarniak ◽

...

Keyword(s):

Mechanical Properties ◽

Carbon Nanotubes ◽

Electrical Conductivity ◽

Copper Foil ◽

Impact Resistance ◽

Mechanical Analysis ◽

Lightning Strike ◽

Single Wall Carbon Nanotubes ◽

Carbon Fibre Reinforced Polymer ◽

The Impact

The main aim of this work was the investigation of the possibility of replacing the heavy metallic meshes applied onto the composite structure in airplanes for lightning strike protection with a thin film of Tuball single-wall carbon nanotubes in the form of ultra-light, conductive paper. The Tuball paper studied contained 75 wt% or 90 wt% of carbon nanotubes and was applied on the top of carbon fibre reinforced polymer before fabrication of flat panels. First, the electrical conductivity, impact resistance and thermo-mechanical properties of modified laminates were measured and compared with the reference values. Then, flat panels with selected Tuball paper, expanded copper foil and reference panels were fabricated for lightning strike tests. The effectiveness of lightning strike protection was evaluated by using the ultrasonic phased-array technique. It was found that the introduction of Tuball paper on the laminates surface improved both the surface and the volume electrical conductivity by 8800% and 300%, respectively. The impact resistance was tested in two directions, perpendicular and parallel to the carbon fibres, and the values increased by 9.8% and 44%, respectively. The dynamic thermo-mechanical analysis showed higher stiffness and a slight increase in glass transition temperature of the modified laminates. Ultrasonic investigation after lightning strike tests showed that the effectiveness of Tuball paper is comparable to expanded copper foil.

Download Full-text