Authors:S. Ľalíková, M. Pajtášová, M. Chromčíková, M. Liška, V. Šutinská, M. Olšovský, D. Ondrušová, and S. C. Mojumdar
the conventional filler. The effect of montmorillonite fillers (Ca-MMT, Co-MMT, Cu-MMT) on the vulcanizing characteristics, physico-mechanicalproperties, and dynamic-mechanical thermal behaviour was investigated at 2 phr filler loading. The
This study was carried out to evaluate some physical and mechanical properties of three Hungarian rice varieties named Dáma, Janka and M488 under different moisture levels to be a useful data for modelling the moisture changes in rough rice storage bins. Rough rice grains were conditioned to moisture contents of 12, 18, 24, and 30% (w.b.). Five mechanical expressions named rupture force (Fr), maximum stress (σmax), grain deformation (D), energy (E) and toughness (T) were extracted from stress–strain curve for all tested varieties as a function of moisture content. Also, some physical properties such as bulk density, true density, porosity and some morphological features of grain were determined as a function of moisture content for tested rough rice grain. The results revealed that the measured physical and mechanical properties are significantly effected by moisture contents for the three tested rice varieties. In general, when the moisture content increased, the rupture force and maximum stress decreased for all investigated grains. However, the deformation, energy and toughness firstly decreased with moisture content increase and after that increased with further increase of moisture content for all rice varieties. On the other hand, the bulk density, true density and porosity do not have a specific trend with increasing moisture content. Moreover, there was a significant difference among the selected rice varieties in terms of their bulk density and porosity at the same moisture content range.
Authors:Lucia Kidalova, Nadezda Stevulova, and Eva Terpakova
All composites based on natural fibers absorb moisture in humid atmosphere and when immersed in water or capillary action. Therefore, one of the major drawbacks of polymer fibers is their high availability to moisture sorption and their heterogeneity, which leads to a weak interface between the fibers and matrix and a poor transfer of the applied stress between the materials, resulting to reduction of physico-mechanical properties. An experimental investigation was conducted to testing the water absorption of hemp composites with MgO-cement binder and its influence on the physico-mechanical and thermal characteristics of composites. The achieved results of composites indicate that water absorption test has deteriorative influence on observed properties due to the degradation of the fibre-matrix interface.
Authors:Ivana Schwarzova, Nadezda Stevulova, Eva Singovszka, Eva Terpakova, and Jozef Junak
This article concerning natural cellulose fibers as reinforcement in composite materials in civil engineering. In this paper, the attention is given to industrial hemp specifically to the woody part of hemp plant called hemp hurds. The properties of natural fibers are mainly determined by the chemical and physical composition, such as structure of fibers.
The objective of presented research is to characterize raw and physically treated hemp fibers using Fourier transform infrared spectroscopy method. These natural fibers were used as filler into biocomposites and MgO-cement was used as alternative binder. Physico — mechanical properties (compressive strength, thermal conductivity, absorbability) of prepared composites were determined.
Authors:Julia Cigasova, Nadezda Stevulova, and Jozef Junak
Islam M. S., Pickering K. L., Foreman N. J. Influence of alkali treatment on the interfacial and physico-mechanicalproperties of industrial hemp fiber reinforced polylactic acid composites, Composites: Part A , Vol. 41, 2010 pp. 596
-Baldúz L. J. , Sáez-Hostaled J. L. , Ramis J. , Olivares D.
Physico-mechanicalproperties of multi-recycled concrete from precast concrete industry , Journal of Cleaner Production , Vol. 141 , 2017 , pp. 248 – 255
Authors:N. Obradović, A. Terzić, Lj. Pavlović, S. Filipović, and V. Pavlović
cement grains, gel porosity has a major effect on hydration rates, the contributions of each of the remaining types of porosity should not be neglected either.
Physico-mechanicalproperties of refractory concrete
Authors:Ivan V. Abramov, Pavel V. Lekomtsev, Аlexander V. Romanov, Аndrey V. Buchkin, Zarina S. Saidova, and Zoltan Orban
primarily due to the different physico-mechanicalproperties (mainly of the working surface hardness) of the steel collet and FRP, low crack resistance of the polymer composite matrix material, relatively low shear strength of FRP due to the absence of