Laboratory and Statistical Analysis of the Fatigue Response of Self-Healing Asphalt Mixtures Containing Metal By-Products

Fatigue is one of the main forms of deterioration in asphalt mixtures, endangering their service life due to the progressive appearance and expansion of cracks. A sustainable approach to increase the lifetime of asphalt pavement has been found in self-healing technology, especially if boosted with metal by-products due to their economic and environmental interest. Under these circumstances, this research addressed the fatigue behavior of self-healing asphalt mixtures including industrial sand blasting by-products obtained from sieving and aspiration processes. Hence, a uniaxial fatigue test was carried out to determine whether these experimental mixtures can provide a similar response to that of a reference asphalt concrete (AC-16). This analysis was undertaken with the support of descriptive and inferential statistics, whose application proved the absence of significant differences in the fatigue performance of self-healing experimental mixtures with respect to conventional asphalt concrete. These results suggest that designing self-healing mixtures with metal by-products is a sustainable approach to increase the lifetime of asphalt pavements, while contributing to the circular economy through diverse economic and environmental benefits.

BOTTOM FAUNA OF LAKE DONUZLAV UNDER CONDITIONS OF INDUSTRIAL SAND MINING

In 2019, the composition and quantitative representation of the zoobenthos in Donuzlav Lake, in the area of fine sediment discharge after the sand mining, and in the adjacent water area were studied. The accounting of the macrozoobenthos at the species level and of the meiobenthos at the major taxa level indicates the presence of a typical Pontic bottom fauna in the Lake, which has developed over 58 years of it existence. The benthic macrofauna was represented by a biocoenosis of Chara algae with Mytilaster lineatus, existing in a two-tier biotope – of a soft-bottom and of a Chara algaes developing on it. The epiphyton macrofauna quantitatively dominated the benthic macroinfauna. A total of 102 species and 7 superspecies taxa of the macrozoobenthos were registered in the identified biocoenosis. That increases the overall level of the macrozoobenthos representation up to 171 species and 9 superspecies taxa in Donuzlav for the period since 1981. In meiobenthos 11 taxa in the rank of type were recorded. The abundance and biomass of the macrozoobenthos averaged 34.658±1.655 ind./m2 and 316±93 g/m2 respectively, that is comparable with the previous studies. The average abundance of meiobenthos in the bottom biotope reached 247.2×103 ind./m2. Nematodes were the dominant group in meiobenthos, followed by harpacticids, with a combined share of 81 % in total meiobenthos abundance. The local impact of the discharging finely dispersed soil fractions to the benthic fauna of the southern part of the Donuzlav Lake was revealed. There was a 12, 3.5 and 2-fold decrease in abundance, biomass and number of macrozoobenthos species respectively and a 3.2-fold decrease in meiobenthos abundance, in the discharging area compared to the neighboring water areas of the Lake.

Effect of sand particles (50 wt%) on strength and resistance of epoxypolymer composite materials

The sands of various dispersion&origin can watch as basic filler for tonnage build & industrial compounds. The work is devoted to the urgent topic of obtaining cheapened epoxy materials with a high content of natural and building sand. In the case of composite optimization, it is possible to obtain valuable competitive multitonnage composites, moreover, while maintaining the original performance properties or even improving them. In our work, the sand from Ukrainian mines & rivers were used. It is tree types of sand: A) “Quarry” – from industrial carrier in nord of Ukraina; B) “Bottom” – from bottom of big river (Desna); C) “Fabric” – industrial sand TM Stark, Ukraina. A number of practically important properties of composite materials based on epoxy resin and sand of various types and dispersions (50 wt%) have been established. It is shown that 50 wt% of all used sands leads to essential increasing of AbrasiveResistance and SwellingResistance, and microhardness. At same time, 50%-filling decreases investigated strength parameters (to compression & to bending). Is important that sands let reach a high esthetic characteristics of composites: in this simple method can obtain wood-, stone-, honey-like composite materials for building, design & décor. The prospects for the implementation of these results are quite wide, since they cover both large-tonnage construction and repair, innovative industries, as well as small repair segments that are now developed (car service, museum restoration) and handmade. At the same time, this work only opens up these prospects and can become the basis for further scientific and practical research

Fiber Concrete for Industrial and Civil Construction

In the article the questions of application of a steel fiber for disperse reinforcing of fine-grained concrete are considered. Main filler of a fiber concrete mix was the KMA industrial sand enriched with sand. The carried-out researches showed advantage of a steel wave fiber before the anchor and flat milled. The optimal type of fiber is revealed, in which the greatest increase of strength and deformation characteristics is observed. Thus, it can be concluded that the type of steel reinforcing fiber and its shape have a significant impact on the length of building structures and buildings as a whole.