Thermal and Optical Investigation of Lime Mortar for Repetitive Thermal Loading
01 Jan 2020-Vol. 58, pp 245-255
TL;DR: In this paper, a detailed pore distribution analysis has done using digital image processing tool for better interpretation of thermal damages in lime mortar, which can be used as aided tool for retrofitting and conservation of many architectural heritages.
Abstract: Lime-based mortar interlayer plays an important role in structural and architectural construction. Lime mortar undergoes repetitive changes in temperature when it is exposed to its service environment. Change in temperature has a significant effect on the thermal deformation of cement mortar and even affects directly the durability of century decade monuments and structure under extreme regions. This paper deals with thermal deformation of lime mortar, which is the prime constituent of cement and the oldest construction material by measuring its deformed geometrical configuration. In the first part, it is aimed to investigate the thermal deformation of mortar cube, its changes in length and mass of the specimens continuously measured during the heating and cooling cycles within the range of temperatures of −20 to 70 °C. The second part of this paper aims to investigate the pore formation and pore size distrubution in lime and lime mortar sample using optical microscopic images. Although a careful visual inspection can provide very good accuracy information, it has inherent limitations in assessing the structural integrity, and also, visual inspection can provide limited information to a damaged facility. In this paper, a detailed pore distribution analysis has done using digital image processing tool for better interpretation of thermal damages in lime mortar. The above-proposed tool can be used as aided tool for retrofitting and conservation of many architectural heritages.
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01 Jan 1983
TL;DR: The main features of the behaviour of steel at high temperature are summarized and discussed in this article, where the authors identify those properties and characteristics, which are of importance, survey the existing knowledge, evaluate the data and the relevant literature, suggest activity in areas not already covered and provide facilities for the dissemination of information in papers and by discussion.
Abstract: The objectives of the technical committee are to identify those properties and characteristics, which are of importance, survey the existing knowledge, evaluate the data and the relevant literature, suggest activity in areas not already covered and provide facilities for the dissemination of information in papers and by discussion. In this report the main features of the behaviour of steel at high temperature are summarized and discussed.
36 citations
TL;DR: In this paper, the grain size distribution of 30 Belgian Cenozoic sands was studied using point counting and image analysis, and the results of the quantitative mineralogical analysis of the sands obtained through point counting indicate overall depositional or diagenetical influences.
13 citations
TL;DR: In this paper, the results of the experimental investigation of the developing expansion and contraction strains of both plastering mortar and Expanded Polystyrene Foam (EPS) coatings, during thermal and drying cyclic loading are presented.
Abstract: The results of the experimental investigation of the developing expansion and contraction strains of both plastering mortar and Expanded Polystyrene Foam (EPS) coatings, during thermal and drying cyclic loading are presented. The mortar used, is cement based with hydrated lime and fine marble aggregates. The EPS specimens were cut from boards of various qualities, appropriate for the external insulation of buildings. Mortar and EPS specimens were subjected to temperature cyclic changes, during which the occurring expansion and contraction strains were recorded. Based on these data, assumptions were made for the nature and the mechanism of the growing strains, in order to collect the necessary information to develop solutions for the critical problem of mortar cracking when applied over EPS insulating boards.
6 citations
TL;DR: A technique for preparing, curing, and autoclaving 1by 1by 10-inch cement-lime bars was developed, and the expansive characteristics of 80 commercial hydrated limes were determined as discussed by the authors.
Abstract: A technique for preparing, curing, and autoclaving 1by 1by 10-inch cement-lime bars was developed, and the expansive characteristics of 80 commercial hydrated limes were determined. On the basis of chemical analysis and percentage of unhydrated oxide, the hydrated limes were classified into four series: high-calcium, regularly hydrated dolomitic, highly hydrated dolomitic, and magnesian. Data on the expansions of cement-lime bars prepared in the proportions of 2 parts cement to 1 part lime, 1 part cement to 1 part lime, and 1 part cement to 2 parts lime, by weight, and autoclaved to 295 pounds per square inch gage pressure for 3 hours, showed that bars prepared with the regularly hydrated dolomitic limes, which had the highest percentages of unhydrated oxides, had the highest percentages of expansion. The high-calcium limes, characterized, in general, by the lowest percentages of unhydrated oxides, gave the lowest percentages of expansion. Most of the highly hydrated dolomitic limes had percentages of unhydrated oxide and expansion that were comparable to those of the high-calcium limes. An increase in the proportion of lime in the cement-lime bars was attended by an increase in expansion. The method for determining the linear expansion of cement-lime bars autoclaved at a steam-gage pressure of 295 lb/in. (equivalent to a temperature of 216° C.) was found to be reproducible, by three independent operators. The effect of 17 different Portland cements on the expansion of cement-lime bars showed that the expansion values for a particular lime tended to increase as the expansion value of the constituent cement increased. Arbitrarily subtracting the i expansion of the neat cement from the total expansion gave the most uniform result for the "net" expansion of the lime. With an autoclave specially modified for ascertaining the behavior of cement-lime bars during the course of autoclaving, it was found that only a slight amount of the total expansion occurred before a temperature of 150° C. was reached, but above 150° C. a rapid expansion rate was noted, which in turn tapered off before a temperature of 216° C. was reached. Retarding the rate of heating resulted in a decrease in the total expansion. Finally, from criteria set forth for a procedure for determining the soundness of hydrated limes, a test is proposed with a suggested limit of expansion of 1.0 percent.
5 citations