A Micromechanical-Based Investigation on the Frictional Behaviour of Artificially Bonded Analogue Sedimentary Rock with Calcium Carbonate

Author(s):  
Jing Ren ◽  
Huan He ◽  
Kostas Senetakis
2018 ◽  
Vol 4 (1) ◽  
pp. 45
Author(s):  
Lucky Budiman ◽  
Silvia Sukirman

ABSTRAKPerkerasan jalan adalah campuran antara agregat dan bahan pengikat, berfungsi melayani beban lalu lintas. Agregat yang biasa digunakan untuk perkerasan jalan adalah batu pecah dan bahan lainnya. Batu kapur adalah batuan sedimen yang terusun dari kalsium karbonat (CaCO3) dalam bentuk mineral kalsit. Batu kapur merupakan salah satu mineral industri yang banyak digunakan oleh sektor industri dan konstruksi. Tujuan penelitian ini antara lain untuk mengetahui karakteristik batu kapur dan penggunaan batu kapur Kalipucang sebagai substitusi agregat halus dari campuran beton aspal jenis AC-BC, dengan penambahan batu kapur sebanyak 50% dari dari agregat halus. Berdasarkan hasil analisis data pengujian didapatkan nilai stabilitas dari beton aspal substitusi batu batu kapur lebih tinggi dibandingan dengan campuran beton aspal tanpa batu kapur, yaitu 1.800 kg untuk campuran substitusi batu kapur dan 1.600 kg untuk campuran tanpa batu kapur. Sifat volumetrik beton aspal dari kedua campuran yaitu    dan  memenuhi spesifikasi yang telah ditentukan.Kata kunci: laston AC-BC, batu kapur, substitusiABSTRACTThe pavement street is a mixture between of aggregates and binders,the function is serving the traffic load. The aggregate commonly used for street pavement are broken stone and other materials. Limestone is sedimentary rock are composed of calcium carbonate (caCO3) in the mineral form of calcite.Limestone is one of a mineral an industry that is much used by the industrial and construction sectors. The purpose of this research include to know characteristic limestone and the use of limestone Kalipucang as a substitution of fine aggregate from a mixture of asphalt concrete of AC-BC,by the addition of limestone 50% of the fine aggregate. Based on the results of data analysis testing obtained the value of the stability from concrete asphalt  the substitution of limestone higher than being with a mixture of asphalt concrete without limestone, that is 1,800 kg to mixed the substitution of limestone and 1,600 kg to mix without limestone. Volumetric properties of asphalt concrete of two mixetures is    and meet specifications which has been determined.Keywords: laston AC-BC, limestone, substitution


2017 ◽  
Vol 32 (3) ◽  
pp. 88
Author(s):  
Jonatas Malaquias Otavio ◽  
Osvaldo Girão ◽  
Tiago Fernando de Holanda ◽  
Wenderson Sávyo Aguiar Da Silva

Os arenitos de praia, ou beachrocks, são sedimentos que sofreram um processo de litificação e são encontrados paralelamente à linha de costa na zona intermaré, apresentando uma forma alongada, estreita e cimentados por carbonato de cálcio. O processo de diagênese consiste na formação da rocha sedimentar propriamente dita a partir da compactação, dissolução, cimentação e recristalização. O estudo da formação e diagênese do arenito de praia são relevantes pois possibilita o entendimento de como as rochas sedimentares detríticas são geradas, além de reconhecer como a variação do nível do mar se comportou durante o Holoceno, permitindo a gênese destas feições que se constituem em relevantes elementos de resguardo das linhas de costas em ambientes majoritariamente tropicais. FORMATION AND DIAGENÈSE IN BEACHROCKS:A Conceptual Review ABSTRACTThe beach sandstones, or beachrocks, are sediments that underwent a lithification process and are found parallel to the coastline in the intertidal zone, presenting an elongated, narrow shape and cemented by calcium carbonate. The process of diagenesis consists on the formation of the sedimentary rock itself, following deposition, compaction, dissolution, cementation and recrystallization. The study of the formation and diagenesis of beach sandstone is relevant since it permits the understanding of how clastic sedimentary rocks are formed, besides with recognizing how sea level variation behaved during the Holocene, thus allowing the genesis of these features that constitute relevant elements of shelter along coastlines in most tropical environments. Keywords: Beachrocks, sedimentary rock, cementation.


Author(s):  
S. Q. Xiao ◽  
S. Baden ◽  
A. H. Heuer

The avian eggshell is one of the most rapidly mineralizing biological systems known. In situ, 5g of calcium carbonate are crystallized in less than 20 hrs to fabricate the shell. Although there have been much work about the formation of eggshells, controversy about the nucleation and growth mechanisms of the calcite crystals, and their texture in the eggshell, still remain unclear. In this report the microstructure and microchemistry of avian eggshells have been analyzed using transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS).Fresh white and dry brown eggshells were broken and fixed in Karnosky's fixative (kaltitanden) for 2 hrs, then rinsed in distilled H2O. Small speckles of the eggshells were embedded in Spurr medium and thin sections were made ultramicrotome.The crystalline part of eggshells are composed of many small plate-like calcite grains, whose plate normals are approximately parallel to the shell surface. The sizes of the grains are about 0.3×0.3×1 μm3 (Fig.l). These grains are not as closely packed as man-made polycrystalline metals and ceramics, and small gaps between adjacent grains are visible indicating the absence of conventional grain boundaries.


TAPPI Journal ◽  
2012 ◽  
Vol 11 (5) ◽  
pp. 53-61 ◽  
Author(s):  
PATRICK HUBER ◽  
SYLVIE NIVELON ◽  
PATRICE NORTIER

Calcium carbonate scaling often is a critical problem for recycled board mills that have closed water circuits. The objective of this study was to determine local scaling risks throughout the production process. To predict scaling potential, we calculated several saturation indexes, based on speciation determined from detailed water analyses. Calculated scaling trends are in accordance with observed dissolution and precipitation of calcium carbonate in the process, when considering local aeration phenomena. The importance of volatile fatty acids (resulting from anaerobic bacterial activity) in calco-carbonic equilibriums is discussed, and taken into account in the speciation calculation. We also demonstrate the need to measure inorganic carbon instead of alkalinity in such conditions. This makes typical scaling indexes, such as the Ryznar Stability Index, irrelevant to predict scaling risk in closed circuit conditions; thus, it is necessary to use general speciation methods, as described in this paper.


TAPPI Journal ◽  
2011 ◽  
Vol 10 (7) ◽  
pp. 29-34
Author(s):  
TEEMU PUHAKKA ◽  
ISKO KAJANTO ◽  
NINA PYKÄLÄINEN

Cracking at the fold is a quality defect sometimes observed in coated paper and board. Although tensile and compressive stresses occur during folding, test methods to measure the compressive strength of a coating have not been available. Our objective was to develop a method to measure the compressive strength of a coating layer and to investigate how different mineral coatings behave under compression. We used the short-span compressive strength test (SCT) to measure the in-plane compressive strength of a free coating layer. Unsupported free coating films were prepared for the measurements. Results indicate that the SCT method was suitable for measuring the in-plane compressive strength of a coating layer. Coating color formulations containing different kaolin and calcium carbonate minerals were used to study the effect of pigment particles’ shape on the compressive and tensile strengths of coatings. Latices having two different glass transition temperatures were used. Results showed that pigment particle shape influenced the strength of a coating layer. Platy clay gave better strength than spherical or needle-shaped carbonate pigments. Compressive and tensile strength decreased as a function of the amount of calcium carbonate in the coating color, particularly with precipitated calcium carbonate. We also assessed the influence of styrene-butadiene binder on the compressive strength of the coating layer, which increased with the binder level. The compressive strength of the coating layer was about three times the tensile strength.


TAPPI Journal ◽  
2019 ◽  
Vol 18 (10) ◽  
pp. 595-602
Author(s):  
ALISHA GIGLIO ◽  
VLADIMIROS G. PAPANGELAKIS ◽  
HONGHI TRAN

The formation of hard calcite (CaCO3) scale in green liquor handling systems is a persistent problem in many kraft pulp mills. CaCO3 precipitates when its concentration in the green liquor exceeds its solubility. While the solubility of CaCO3 in water is well known, it is not so in the highly alkaline green liquor environment. A systematic study was conducted to determine the solubility of CaCO3 in green liquor as a function of temperature, total titratable alkali (TTA), causticity, and sulfidity. The results show that the solubility increases with increased temperature, increased TTA, decreased causticity, and decreased sulfidity. The new solubility data was incorporated into OLI (a thermodynamic simulation program for aqueous salt systems) to generate a series of CaCO3 solubility curves for various green liquor conditions. The results help explain how calcite scale forms in green liquor handling systems.


2017 ◽  
Vol 137 (9) ◽  
pp. 536-541
Author(s):  
Tomohiro Kawashima ◽  
Tomohiro Yamada ◽  
Yoshinobu Murakami ◽  
Masayuki Nagao ◽  
Sou Ozaki ◽  
...  

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