Assessment of technological properties of calcareous and non-calcareous clays used for the brick-making industry of Zaragoza (Spain)
The granulometric, mineralogical, and geochemical features of two different types of clayey raw materials (carbonated clays, CC; and non-carbonated clays, NCC) used for the brickmaking industry near Zaragoza (Spain) have been studied. Their particle-size distribution suggests that they may be classified as silty clays and are suitable for use as thin-walled hollow bricks. For technological testing, prismatic bars obtained by extrusion under vacuum conditions from raw materials were fired from 800 to 1050 °C. Technological determinations, such as linear shrinkage, bulk density, hydric tests, and an accelerated decay test, indicate that both CC and NCC are suitable to be used as bricks for building, although bricks made of NCC would be of better quality. In addition, pore-size distribution suggests that the durability of the highest temperature fired products will be higher because of an increase both in the dominant pore access radius and in the percentage of larger pore sizes.
Characteristics of some clay materials from Tamilnadu, India, and their possible ceramic uses (Características de algumas argilas de Tamilnadu, India, e seus possíveis usos cerâmicos)
AbstractX-ray fluorescence, themogravimetric-differential thermal analysis, Fourier Transform Infrared spectroscopy, X-ray diffraction, particle size analysis and Atterberg limits were used to study physico-chemical, mineralogical and thermal properties of two types of clays from four different locations of Tamilnadu, India. The chemical and mineralogical compositions of these clays differ considerably. The mineralogy indicated that the alluvial clays (G1 and G2) comprise highly quartz, illite, kaolinite, plagioclase and small amount of chlorite. The red clays (R1 and R2) were also rich in quartz, well-ordered kaolinite and abundant Fe-bearing minerals such as goethite and hematite. With respect to chemical composition, the G1 and G2 clays contained high amount of SiO 2 , low amount of Al 2 O 3 and low loss on ignition, however, the R1 and R2 clays contain moderate amount of SiO 2 , Al 2 O 3 , and high amount of Fe 2 O 3 and high loss on ignition. The results indicate that clays from alluvial deposit have adequate characteristics for common brick fabrication. However, clays collected from red clay deposit possessing adequate properties for roofing tile manufacturing and can be used for the manufacturing of common brick with some modification. Keywords: alluvial clay, red clay, clay, plasticity, brick, tiles.ResumoAs tecnicas de fluorescencia de raios X, analise termogravimetrica-termica diferencial, espectroscopia no infravermelho com transformada de Fourier, difracao de raios X, analise de tamanho de particulas e limites de Atterberg foram utilizadas para o estudo de propriedades fisico-quimicas, mineralogicas e termicas de dois tipos de argilas de quatro diferentes localizacoes em Tamilnadu, India. As composicoes quimicas e mineralogicas dessas argilas diferem consideravelmente. A mineralogia indica que argilas aluviais (G1 and G2) sao compostas principalmente de quartzo, ilita, caulinita, plagioclases e pequenas quantidades de cloretos. As argilas vermelhas (R1 and R2) sao tambem ricas em quartzo, caulinita bem ordenada, e minerais abundantes em ferro tais como goetita e hematita. Com relacao a composicao quimica, as argilas G1 e G2 contem alto teor de SiO
Comparison of different antenna configurations for probing of layered media
The paper presents the results of a comparative analysis of the different configurations of antenna systems (bistatic, monostatic, differential) in terms of the simplicity and accuracy of determining the thickness of the subsurface layers of stratified environment. To this end, corresponding diffraction problems are solved by the finite-difference time-domain forward solver for each measurement setup. The analysis has shown the advantages and prospects of using differential system with vertically spaced antennas in solving of practical problems of the layered medium GPR probing.