Wyniki wyszukiwania - BazTech

1

Comparative analysis of strains and durability of asphalt pavement of perpetual and standard type

Nagórski R., Błażejowski K., Marczuk K.

Roads and Bridges - Drogi i Mosty

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2012

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Vol. 11, no. 4

311-327

EN

This paper analyses the key strains and fatigue performance of the following types of road pavements using fatigue cracking and subgrade rutting as the evaluation criteria: conventional asphalt pavement and pavement structure with fatigue-resistant layer (as in perpetual pavement concept). Calculations were performed for two wheel speeds: 60 km/h and 5 km/h. The study included a comparison of results obtained for pavements differing in terms of material specifications and structure: reference model built of only elastic layers and two models built of viscoelastic asphalt layers and layers of aggregate cement-treated base (CTB) on soil subgrade. The determinations included strains, deformation and displacements (for which VEROAD software program was used) also the above-mentioned failure criteria determined using the Asphalt Institute equations. For predicting the fatigue life of pavement the lower asphalt layer was assumed to have the modulus value equal to the initial modulus calculated with Van der Poel equation and dynamic moduli calculated as sensitive or insensitive to the wheel speed respectively. The effect of the respective factors on the life of pavement in million standard axles (msa) was assessed, demonstrating that the calculations assuming elastic behaviour of all the pavement layers lead to overestimating the pavement life. Finally, it was found that the wheel speed had a significant effect on the strain and on the fatigue life of pavement.

PL

W pracy dokonano analizy kluczowych odkształceń oraz trwałości obliczeniowej według kryteriów spękania zmęczeniowego i deformacji podłoża w układzie warstwowym nawierzchni drogowej skonstruowanej według wariantów: standardowej nawierzchni asfaltowej oraz stan-dardowej nawierzchni z warstwą przeciwzmęczeniową (jak w koncepcji nawierzchni perpetual). Przyjęto obciążenie ruchome o dwóch prędkościach, tj. 60 km/h i 5 km/h. Porównywano wyniki dla każdego typu nawierzchni przy różnych założeniach materiałowych i konstrukcyjnych: model odniesienia ze wszystkimi warstwami sprężystymi i dwa modele składające się z lepkosprężystych warstw asfaltowych oraz ze sprężystych warstw z kruszywa, ulepszonego podłoża stabilizowanego cementem i podłoża gruntowego. Oprócz wyznaczenia naprężeń, odkształceń i przemieszczeń obliczono, korzystając z wzorów Instytutu Asfaltowego, wymienione na wstępie miary trwałości nawierzchni. W formule na odporność na spękania zmęczeniowe jako moduł sztywności dolnej warstwy asfaltowej podstawiono moduł początkowy Van der Poela oraz moduł dynamiczny obliczony jako niezależny lub zależny od prędkości obciążenia. Dokonano oceny wpływu poszczególnych czynników na trwałość nawierzchni wyrażoną w milionach osi obliczeniowych, wykazując, że model całkowicie sprężystych warstw zawyża obliczoną trwałość. Wykazano także istotny wpływ prędkości pojazdów na odkształcenia oraz na trwałość zmęczeniową.

2

Spectroscopic studies of the copper-cadmium halide photochromic glasses

Marczuk K., Mirowska N.

Optica Applicata

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2005

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Vol. 35, nr 4

859-867

EN

The spectra of optical absorption, luminescence excitation and photoluminescence in the range of 200-750 nm in the Cu-Cd-photochromic glasses were measured. As a matrix of photochromic glass the sodium-borosilicate glass was used. The absorption within the UV wavelength range (200-300 nm) is connected to various structural defects of the matrix glass. The changes of the optical absorption and photoluminescence excitations resulting from the UV radiation in the Cu-Cd-photochromic glasses have been analysed. It was noticed the share of the matrix glass structure components in creation of the colour centers stable of room temperature.

3

Studies of the properties of copper-cadmium photochromic glasses.

Rysiakiewicz-Pasek E., Marczuk K., Ziemba B

Optica Applicata

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2000

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Vol. 30, nr 4

671-676

EN

The properties of photochromic glasses containing copper and cadmium chloride were investigated. The influence of the temperature and time of heat treatment on the change of the glass structure was considered. The parameters (coefficients) determining the bleaching process were calculated. To study the structure of photochromic glasses after heating the thermally stimulated depolarization technique was applied. The origin of TSDC peaks was discussed.

4

Influence of gamma -irradiation on the photoluminescent properties of porous glasses.

Gevelyuk S.A., Lishchuk D.E., Mak V.T., Rysiakiewicz-Pasek E., Marczuk K.

Optica Applicata

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2000

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Vol. 30, nr 4

595-603

EN

The influence of small doses of gamma -irradiation on the features of the photoluminescence spectra of porous silica glass during long-time (several months) storage after the irradiation is investigated. The non-monotonic dependence of photoluminescence change on the dose of the glasses with a different composition and different additional pre-treatment is observed. The analysis of intensity changes and shifts of the maxims of the photoluminescence spectra shows long-time oscillations. This indicates that the composite catalytic processes take place on the surface of the pores. Perhaps the small gamma -radiation doses initiate the cyclic process of the surface state transformation on the inner side of the pores.

5

High temperature treatment of porous glasses.

Marczuk K., Pater K.

Optica Applicata

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2000

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Vol. 30, nr 4

619-625

EN

The influence of thermal treatment on linear sizes and the internal structure of porous glasses has been investigated. A simple connection between porosity and shrinkage has been confirmed to exist except in microporous glasses with silica gel inside the pores, where in the initial stage of annealing the porosity was increasing when the glass shrank. A sponge structure of fracture mirrors of the walls of a carcass for glasses heated at about 650 degrees C is observed.