The chemometric study of limestone physico-chemical properties and thermal behavior for application in construction composites

Abstract

The limestone, as an economically sustainable and easily available basic raw material, is frequently utilized in the building industry for resolving of the environmental protection issues. The limestone is incorporated in a cementitious system either by grinding with cement clinker, or by blending with the binder during concrete production. The employing of powdery limestone as partial cement replacement gives the construction composites with properties comparable to that of conventional concrete. The study of limestone thermal behavior and its chemistry is crucial for the prognosis of the designed composites properties. In this work, the instrumental techniques (atomic emission spectroscopy, differential thermal and thermo-gravimetric analysis, Fourier transform infrared spectroscopy) and the Principal component analysis were employed to discriminate and classify 22 limestone types. The PCA statistical method, as a means of spectra and experimental data fingerprinting, grouped the samples in a multi-dimensional factor space producing four graphical prognosis - one for each instrumental method. DTA/TG peak values varied the most in a short range between 830-870?C, while FTIR spectra showed the highest diversity in the 867-887 cm-1 and 1237-1647 cm-1 ranges. This research was governed by an idea to reveal whether it is possible to differentiate various limestone types and to predict the possibility of their employment in construction composites on the basis of the results of instrumental and mathematical analyses. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. ON 172057, III 45008, TR 31055, TR 34006, and TR 34013]

Investigation in order to defined the technological process of obtaining fillers for use in various industries on the basis of limestone 'Gigovici'-Ulcinj

“…The free carbonate ion belongs to the symmetry point group D 3h . Therefore, the CO 3 2-ion has four normal vibrations of which one belongs to the species A ' 1 , one is of species A ' 2 , while two vibrations belong to the E ' species [2,29]. The carbonate functional group that is present in the calcite corresponds to the D 3h point group as a nonlinear with 4 atoms (N=4).…”

“…Quartz and clay minerals (e.g. kaolinite, hydrous mica, montmorillonite) are other two major limestone constituents [1,2]. Since a substitution of calcium by magnesium occasionally occurs, a limestone that contains 5-35% of Mg is defined as "magnesian limestone".…”

“…Since a substitution of calcium by magnesium occasionally occurs, a limestone that contains 5-35% of Mg is defined as "magnesian limestone". If Mg content is below 5%, the rock is classified as a "high-calcium limestone" [2,3]. The carbonates present in the limestone customarily appear as calcite, aragonite and/or vaterite mineral phases.…”

“…The carbonates present in the limestone customarily appear as calcite, aragonite and/or vaterite mineral phases. However, the only crystal form of real significance is calcite [2,4].…”

“…By being the most abundant, and enclosing at least 50% of all present mineral phases in the limestone, calcite is an important resource and subject of investigations in various scientific fields: mineralogy, chemistry, physics, materials science [2,[7][8][9][10]. Calcite crystallizes rhombohedrally, in a hexagonalscalenohedral class and space group R 3 c.…”