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Nasiąkliwość jako cecha wpływająca na zmianę barwy granitów poddanych działaniu czynników atmosferycznych

Rembiś Marek

Przegląd Geologiczny

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2023

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Vol. 71, nr 11

543--554

EN

The paper presents the results of tests on granite from the Strzegom-Sobótka Massif (Lower Silesia, Poland) and Delicia White granite from the state of Espírito Santo (southeastern Brazil), which were used as paving slabs. Strzegom granite revealed low water absorption - below 0.4% and anisotropy of the capillary absorption coefficient from about 1.1 to about 2.3 g/m2/s. In slabs with a higher value of this coefficient (above 2 g/m2/s), the solutions resulting from the decomposition of some grains (hematite and siderite)from the subgrade aggregate were moved through a system of capillary micro-fissures. As a result, rusty stains appeared on the surface of many slabs, significantly reducing their decorative value. All samples of Brazilian granite were characterized by water absorption with an average value of 0.44% and low anisotropy of the capillary water absorption coefficient in the range of approximately 1. 6-1. 7g/m2/s. The surfaces of the slabs hadpreviously been subjected to thermal treatment. As a result, a near-surface zones with several-millimetre thick microcraks appeared in some of them. In such cases, the value of the capillary absorption coefficient increased to approximately 1.8 g/m2/s. Rainwater containing atmospheric gas and dust particles penetrated the pore space of the rock and reacted with highly weathered biotite and iron oxides and hydroxides. The decomposition products of these minerals dispersed in watermovedthroughasystemofcapillarycrackstowardsthesurfaceofdryingstone,creatingrustyspots.Researchhasshownthata low water absorption value of less than 0.5% is not a sufficient condition to ensure the stone's resistance to the destructive effects of environmental conditions. To assess the suitability of granite for use as an outdoor surface slab, it is also necessary to test its water capillary absorption coefficient. It is acceptable to use granite with a high anisotropy of the capillary absorption coefficient, provided that the method of cutting and laying the slabs ensures the transport of moisture in the direction corresponding to the lowest value of this coefficient.

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Wpływ stopnia wstępnego nasycenia kruszywa z recyklingu na wybrane właściwości i mikrostrukturę betonów recyklingowych

Pawluczuk E., Bołtryk M.

Inżynieria i Budownictwo

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2016

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R. 72, nr 8

413--417

PL

Przedstawiono zagadnienie wpływu stopnia wstępnego nasycenia kruszywa z recyklingu wynoszącego 0; 45 i 90% oraz zróżnicowanej kolejności dozowania składników na wytrzymałość na ściskanie, nasiąkliwość i współczynniki absorpcji wody betonów recyklingowych. Podano wyniki badań strefy kontaktowej między nowym zaczynem i kruszywem z recyklingu.

EN

The article presents the influence of the degree of pre-saturation of recycled aggregate 0, 45 and 90%, and the varied order of ingredients addition, on the compression strength, density, water absorbability and the water absorption coefficient of recycled concrete. An analysis of the contact zone between the new paste and the recycled aggregate was conducted.

3

Incorporation of capillary properties of materials in modeling of courtain walls loaded by the wind-driven rain

Alsabry A.

International Journal of Applied Mechanics and Engineering

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2011

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Vol. 16, no 4

1205-1213

EN

In evaluation of the state of moisture of courting walls one needs data of the intensity of the rainfall on a vertical surface of the construction (wind-driven rain) WDR and of the absorption coefficient of the rain. In this work a mathematical model is presented which allows to estimate the state or moisture of courting wall s under the action of wind-driven rainfalls. This model does not require the use of the average rain absorption coefficient proposed by Kunzel (i.e., it allows to avoid averaging of water absorption ability of the material) and increases the accuracy of the estimation of the state of imbuement of courting walls, in some cases on 30% (depending on climatic conditions).