No abstract

The effect of multi-wall carbon nanotubes and nanosilica (nano SiO2) content on physico-mechanical properties of glass microspheres-epoxy resin composite, designed for blast energy absorbing applications, was evaluated experimentally. Specific porous lightweight foam with high volume fraction of microspheres (70 vol.%) was prepared and modified by 1 to 5 vol.% of multi-wall carbon nanotubes and nanosilica. Compressive and flexural strength tests were conducted at quasi-static load. Split Hopkinson Pressure Bar apparatus was used to obtain high velocity characteristics of the materials. The relative absorbed energy was calculated to assess the relation between the composition of the material and its shock wave attenuation capacity. The mixtures containing nanosilica exhibited an increasing trend in the energy absorption capacity with increasing nanoparticle content up to 4 vol.%. The addition of carbon nanotubes also increased absorbed energy (again up to 4 vol.%, a significant drop was observed at higher concentrations). Comparing the values of the relative absorbed energy, the carbon nanotubes composites prevail over the nanosilica modified ones.

No abstract

No abstract

The effect of fibre type and fibre amount on physico-mechanical properties of slurry infiltrated fibre concrete (SIFCON) at both quasi-static and dynamic load was evaluated experimentally. SIFCON is a special type of cement-based composite with high fibre volume fraction, extremely strong and ductile. Test specimens were prepared with 7 types of steel fibres (with different shape and mechanical parameters) in four volume fractions (7.5-15 vol. %). High performance fibre-reinforced concrete (HPFRC) has also been cast and tested for comparison purposes. The impact test has been carried out by using an in-house manufactured impact testing machine based on drop test principle. The test results revealed that SIFCON slab with 15 vol. % fibre content exhibits superior energy-absorption characteristics when compared to other slab specimens. Diameter of the fibres plays an important role for both strength and energy absorption capacity of SIFCON - using of low-diameter fibres with higher aspect ratio leads to the best results.