Granite Stone Research Articles

Study of Thermal Properties of Granite Powder (Scrap) Reinforced Polyester Resin Composite

Composite materials are now widely used in engineering application and the scope of its application is widespread mainly for its contrapuntal properties. In this research work composites were prepared by crosslinking the polyester resin with Methyl Ethyl Ketone Peroxide and finally reinforced with the Granite scrap powder. Granite stone as filler was used at 20%, 30%, 40% and 50% with respect to the weight of unsaturated polyester resin with styrene monomer at 7.5% as constant basis mentioning that 0% sample (without Granite Filler) was also prepared to compare the results with it. Thermal analysis of the prepared composite such as Thermo Gravimetric Analysis (TGA), Thermo-mechanical Analysis (TMA) and Thermal Conductivity of the composites were analyzed along with the SEM analysis to find out correlation between thermal properties with composite surface topology. Thermo gravimetric analysis is done to determine the kinetics of thermal degradation and Thermo mechanical analysis is to determine expansion co-efficient along with Tg of polyester resin and granite blends composite. To avoid the thermo-oxidative degradation, thermal analysis was carried out for samples in nitrogen atmosphere at heating rates of 20°C/min. Thermal Conductivity analysis is performed to determine the ability of the composite to conduct heat at various temperatures.

ASSESSMENT OF CRACKING RESISTANCE OF CELLULAR CONCRETE PRODUCTS UNDER MOISTURE AND CARBONISATION DEFORMATIONS WITH STRESS RELAXATION

Objectives. On the basis of the experimental, theoretical and field studies, an engineering calculation method was developed for assessing the cracking resistance of external enclosing constructions made of cellular concrete, with the maximum gradient development of moisture and carbonisation forced deformations along their thickness, taking into account the relaxation of the shrinkage stresses. In this regard, the aim of the work is to provide technological measures at the manufacturing stage in order to increase the operational cracking resistance of the construction's outer surface layers by reducing the moisture and carbonation shrinkage of cellular concrete by introducing a large or fine porous aggregate in calculated amounts. Methods. A number of analytical equations were applied to establish the dependence of the shrinkage of heavy concrete of conventional hardness on the amount of aggregate introduced and its elasticity modulus, water-cement ratio and cement consumption, as well as the concrete's moisture content. Results. Knowing the volumes of the structural aggregate and the cellular concrete mass, as well as their modulus of elasticity, the shrinkage reduction factor of the cellular concrete was calculated with the addition of a lightweight porous aggregate. Subsequently, the shrinkage deformations of concrete in the surface layer of the outer enclosing construction, maximising crack resistance due to moisture exchange and carbonation influences under operating conditions, were defined, taking into account the relaxation of tensile stresses due to creep of concrete. Conclusion. Theoretical calculations, based on the recommended method of assessing the cracking resistance of cellular concrete enclosing constructions under moisture exchange and carbonisation processes, taking into account the relaxation of shrinkage stresses, showed that in order to exclude the appearance of cracks in wall panels 280 mm thick made of 700 kg/m3 gas ash concrete with elasticity modulus of 2500 MPa, it is necessary to have 70-80% of keramzite or granulated slag, and 50-60% of stone crumb (granite or marble crushed stone) of the volume of cellular concrete in the surface layer of 30-50 mm.

On Visiting Faulkner’s Grave, and: Before My Mother Moves South, and: Northern Cardinal in Winter, and: Mississippi Gambers after Dusk

On Visiting Faulkner’s Grave, and: Before My Mother Moves South, and: Northern Cardinal in Winter, and: Mississippi Gambers after Dusk Rob Shapiro (bio) On Visiting Faulkner’s Grave He said time is dead as long as it’s beingclicked off by little wheels; only whenthe clock stops does time come to life. i My stepbrother pinned a shotgun shell to his breast pocket when he got married, wore aviators even though dark pastures of clouds brushed above the delta and turned, suddenly, to rain. He planted his footprints deep in the black dirt to see how much the land could hold, how quickly it committed us to memory. And because this was Mississippi, he named his son for himself—the same way his father named him. ii Framed and gawking, the dead decorate my family’s walls— [End Page 64] local ghosts looking out, captured in crops of cotton, the white fields ripe as if blooming with snow. Always, a bloodshot sky just out of reach— always, they refuse to smile for the camera aimed like a pistol at their hearts, its aperture drawing in their sweat-drenched collars and rolled-up sleeves— their work-boots muddied in the same soil tilled year after year. iii When I visited Faulkner’s grave, grazed my hand on the granite stone lined with empty flasks and whiskey fifths, I could have walked the mile down to the house where my stepbrother was raised. And I’ve read of doom, the lord marching his angels out of Mississippi. I’ve read of generations held in the rough arms of countryside— the bluffs and fields and sky. iv He sends photographs to Carolina, prints taken with his father’s old Kodak. I imagine my stepbrother working [End Page 65] the darkroom until dawn: lightheaded from fixer fumes, his fingers uncoiling loose spools of film. Tin sink. Safelight. His son bursting into focus from the shallow darkness— already looking back. Before My Mother Moves South Another week of flurries and frozen rain.You let the sheltie out into the stiffwinter dawn, still thick with stars and fogwhile upstairs, my sister and I sleep—the three of us living togetherfor the last time. Snow-chained truckssand the street, rattle through the darkpast the For Sale sign buriedbeneath our bulldozed banks. Come spring, you’ll be kneelingin the flooded front yard, white statuetteof Saint Joseph held to your chest.Too superstitious not to try prayerto sell the house, you’ll break openthe half-thawed earth and pushthe figurine deep inside the tangled dirt,speaking to it, bargaining. Mother, I want to keep you in that housea little longer, standing by the window [End Page 66] watching the sheltie pace the yardand sink through the melting drifts.The radiator clinks its cast-iron heart;you stir your coffee, spoon rattling rim,and look out at the linden treescradling abandoned nests like palmscupping water—you wait there for the skyto brighten, to disappear behind the rushof snow that falls and clings to nothing. Northern Cardinal in Winter My father is not the feather nor the red crest,but the song sung from the canopies— the slender trill needling through frost and frozen light,woven through the hills outside my bedroom window. And you might think I mean my father is beautifulor far off, some small echo I can’t trace. Truth is, I find he follows like that flickering voice lifting over power linesand fresh snow, that bright fragment I’ve always known. [End Page 67] Mississippi Gamblers after Dusk Gathered on the lawn between the chicken coop and the pond, still high from spring’s thaw, we watch my stepbrother kneel on the jetty beside the thicket of cattails loading tube-launched fireworks. Across the water, rows of barbed wire border the pastures, fence us in as gunpowder cracks like a sheet of ice, sends a Mississippi Gambler streaking across the swath of summer sky until it bursts into light, familiar constellations that drift down, disappear. We grip cans of beer and call to each other...

Radioactivity concentrations and dose characteristics of granite stones

We obtained the radionuclide concentrations of 238U, 232Th, and 40K in various samples of the granite stones by measuring with a high efficiency NaI(Tl) (10.16 cm x 10.16 cm) scintillation detector. The activities of 238U, 232Th, and 40K were recorded and determined by a full-spectrum analysis. The concentrations of radionuclides were found to be in ranges of 32.3-92.6 Bqkg-1, 23.9-52.2 Bqkg-1, and 796.5-2018.4 Bqkg-1 for 238U, 232Th, and 40K, respectively. The radiological dose rates and the hazard indices were also calculated in this analysis.

Measurement and Monte Carlo simulation of γ-ray dose rate in high-exposure building materials

Natural radioactivity radionuclides in building materials, such as 226Ra, 232Th and 40K, cause indoor exposure due to their gamma-rays. In this research, in a standard dwelling room (5.0 m × 4.0 m × 2.8 m), with the floor covered by various granite stones, was set up to simulate the dose rates from the radionuclides using MCNP4C code. Using samples of granite building products in Iran, activities of the 226Ra, 232Th and 40K were measured at 3.8–94.2, 6.5–172.2 and 556.9–1529.2 Bq kg−1, respectively. The simulated dose rates were 26.31–184.36 nGy h−1, while the measured dose rates were 27.70–204.17 nGy h−1. With the results in good agreement, the simulation is suitable for any kind of dwelling places.

Specifics of Studying Crushability of Construction Rocks

Objectives: The existing techniques of studying crushability of rocks are based on the determination of power consumption and aggregate size of the resulting products. Given that during disintegration of the construction rocks it is required to retain rock strength in the crushed stone grains, to improve methodology for crushability assessing is an urgent task. Method: When choosing a method to study crushability of rocks it should be considered that the processes of disintegration in various crushing machines have different mechanisms of action, the most accurate forecast figures are provided by the technique using the destruction mechanism similar to an industrial crusher. A deformation field is created in the entire volume of the body under the load, which leads to a change in the structure and strength of the products formed. In this regard, the strength of crushed stone grains being a final product of disintegration is introduced as an additional indicator that characterizes crushability of rocks. Findings: The article presents the results of studying crushability of construction rocks by different methods. It was found that porosity, particle size, grain shape and loading effort application rate are the factors affecting the strength of crushed stone grains. Mechanical stresses undergone by the rocks during blasting and disintegration result in increased porosity and, consequently, reduce strength. Theoretical dependence of increased strength while reducing the fraction size appears for gabbro-diabases being homogeneous in texture. For granites that are non-uniform in composition and texture there is no unique relationship between the strength and the fraction size. Increased grain cubicity of crushed stone enhances its strength. The study of the crushing kinetics revealed that with decreased loading rate the strength of granite crushed stone having high porosity is reduced, while the strength of the low-porous crushed stone made of gabbro-diabase remains practically unchanged. When choosing a crushing method, either shock or static one, it is necessary to take into account, first, the size of the crushed objects and, second, mineral composition and texture-structural features of the rocks. Improvements: The results obtained are of practical value in selecting rational processing technology and relevant equipment, as well as in the crushing process management to reduce energy costs and improve product quality.

Assessing the weathering of granitic stones on historical urban buildings by geochemical indices

Weathering involves important processes that alter the original structure, texture and chemical components of rocks and minerals. Bulk changes produced by weathering in granitic rocks have been studied by several methods, including chemical weathering indices. They are based on the assumption that some ions are more easily leached from minerals in relation to others. Such methods have also been briefly tested on building stone but not in urban environments, where fast stone weathering rates are typically observed, mainly due to interaction of minerals with several pollutants and where other specific processes, such as salt weathering, can occur. The aim of this work is to discuss the use of weathering indices in the study of weathering rates on granitic stones applied in four historical buildings of an urban area. Results suggest that some factors can cause scatter of results in the relation indices vs. exposition age in the built environment, namely previous weathering degree in rock massifs and the quarry, different orientation of façades and different exposure to urban pollutants. Indices that consider some highly mobile cations that are present in other building materials (namely Ca that is related to leaching from mortar joints) should be avoided due to the uptake of such elements by the stone pores or used to assess this some types of weathering. Moreover, the use of some indices shows more reliable results. Evaluación de la meteorización de rocas graníticas en edificios históricos urbanos por medio de indices geoquímicos ResumenLa meteorización implica importantes procesos que alteran la estructura, textura y componentes químicos originales de las rocas y minerales. Los cambios producidos por la meteorización en rocas graníticas han sido estudiados por varios métodos, incluyendo los índices de meteorización química. Éstos se basan en la suposición de que algunos iones son lavados de los minerales más fácilmente que otros. Tales métodos también se han probado, aunque en pocos casos, en rocas de edificios, pero no de ambientes urbanos, en donde se han observado típicamente elevadas tasas de meteorización, principalmente por la interacción de los minerales con varios compuestos contaminantes y en dónde otros procesos específicos, tales como la erosión por sales, pueden producirse. El objetivo de este trabajo es discutir el uso de índices de meteorización en el estudio de las tasas de meteorización de rocas usadas en cuatro edificios históricos de un área urbana. Los resultados sugieren que algunos factores pueden causar la dispersión de los resultados obtenidos a través de los índices en relación al tiempo de exposición en el ambiente construido, principalmente por el grado de meteorización previo de la roca en los macizos rocosos y en la cantera, la orientación de las fachadas y la diferente exposición a compuestos contaminantes. Los índices que consideran algunos cationes altamente móviles que están presentes en otros materiales de construcción (principalmente el Ca que se relaciona con la meteorización de morteros en las juntas) deben ser evitados debido a que penetran en los poros de las rocas de edificios o deben ser usados para evaluar algunos tipos de meteorización. Por otra parte, el uso de algunos índices muestra resultados más fiables.

Relationships between indoor radon concentrations, thermal retrofit and dwelling characteristics

A monitoring campaign was conducted on a sample of more than 3400 dwellings in Brittany, France from 2011 to 2014. The measurements were collected using one passive dosimeter per dwelling over two months during the heating season, according to the NF ISO 11665–8 (2013) standard. Moreover, building characteristics such as the period of construction, construction material, type of foundation, and thermal retrofit were determined using a questionnaire. The final data set consisted of 3233 houses with the measurement results and the questionnaire answers. Multivariate linear regression models were applied to explore the relationships between the indoor radon concentrations and building characteristics, particularly the thermal retrofit.The geometric mean of the indoor radon concentration was 155 Bq m−3 (with a geometric standard deviation of 3). The houses that had undergone a thermal retrofit had a higher average radon concentration than those that had not, which may have been due to a decrease in air permeability of the building envelope following rehabilitation work that did not systematically include proper management of the ventilation. Other building characteristics, primarily the building material and the foundation type, were associated with the indoor radon concentration. The indoor radon concentrations were higher in older houses built with granite or other stone, with a slab-on-grade foundation and without any ventilation system.

Passive and active methods for Radon pollution measurements in historical heritage buildings

Radon is a dangerous pollutant causing lung cancer. The main protection against it is the monitoring. Recent literature has highlighted that historical buildings and archeological sites could be polluted by Radon not only due to the geological site but also due to the building materials and usage. In this paper, measurement techniques for the evaluation of Radon’s concentration level (222Rn) are compared. This evaluation allows to determine most appropriate technique to be used in this type of buildings. The study is justified by the fact that the buildings are often attended not only by specialists but also by tourist that with their behaviour could misstate Radon gas measurement. The study is effectuated analyzing the situation of three old churches located in San Giovanni in Fiore (Cosenza, south of Italy). The measurement results are compared with the ones obtained by performing the same monitoring in public buildings attended by different kind of users. The monitored sites, churches and public buildings, are erected on the common granite massif of Sila (South Italy), by using local granite stone.

Substrates for biofilter in recirculating system in Nile tilapia larviculture production

SUMMARY Recirculating water system (RAS), provide to reduce water usage and to improve the quality by nutrient recycling, so biofilters are used to reduce ammonia concentrations by oxidation to nitrate, by nitrifying-bacteria. Biological filters have been utilized to maintain acceptable water parameters to larvae and juveniles, by decreasing ammonia concentrations. The objective of this experiment was to evaluate different substrates for aquarium biofilter on performance of Nile tilapia (Oreochromis niloticus) larvae, and water quality. One-thousand-two-hundred Nile tilapia larvae (initial length = 11.6 ± 0.82 mm; body weight (BW) =189.0 ± 0.44mg) were randomly allotted into one of twenty 6-L aquariums (60 larvae aquarium-1) with five different biofilter (4 aquariums each biofilter): (1) control, no substrate; (2) seashell-and granitic crushed stone-substrate; (3) granitic crushed stone substrate; (4) quartz gravel substrate; and (5) porcelain-substrate. The conductivity, turbidity, pH, nitrate, nitrite and ammonia values indicate that seashell and granitic crushed-stone, and porcelain-substrates had greater process of biofiltration effectiveness. Water oxygen did not differ among treatments, with all levels within the benchmark for the tilapia larvae. Fishes reared in aquarium with quartz gravel-and porcelain substrate fishes had greater BW, total and standard length compared with its from other substrates. Porcelain-substrate biofilter is indicated for tilapia larviculture due to improved weight and length and water quality.

Experimental investigation of surface modified EOF steel slag as coarse aggregate in concrete

An experimental work was carried out to study the effect of Energy Optimizing Furnace (EOF) steel slag as coarse aggregate replacement in concrete. Surface modification of slag was carried out to seal the surface voids of raw slag aggregates. Quarry dust obtained as an extractive waste from the granite stone quarries has been used as a blending material in this work. After several trials, it was found that a mix proportion of 1:6:14 (cement:quarry dust:slag aggregate) was the most suitable mix ratio for the surface modification of the slag aggregates. Various mixes of concrete were prepared with different proportions of modified slag (ranging from 0% to 100%) as replacements for aggregates. Three grades of concrete (20MPa, 30MPa and 40MPa) were used in the investigation and the concrete mixes were evaluated for compressive strength and splitting tensile strength. It was found that the compressive strength improved for 25 percent replacement of natural coarse aggregates. The splitting tensile strength was found to peak at 25 percent replacement of natural aggregates.

Analysis of Vitrification Processes and Characteristics of Geochang Granite Stone Sludge for Desulfurization Sorbent of MCFC

The vitrification processes and characteristics of Geochang granite stone sludge were investigated for the application of desulfurization sorbent of Molten Carbonate Fuel Cell (MCFC). From the X-ray fluorescence analysis (XRF) results using Geochang granite stone sludge, it was confirmed that the network formers (SiO₂ and Al₂O3) in granite stone sludge were present between 83.2 and 87.2 wt% and the rest was comprised of network modifiers (K₂O, Na₂O, CaO, Fe₂O3 and MgO). When Borax (Na₂B₄OSUB7/SUB-10H₂O) was added in the granite stone sludge system for promoting the decomposition and reducing the melting viscosity of refractory SiO₂ and Al2O3 comprising of stone sludge, it was observed that the melting point of the granite stone sludge system was reduced by more than 400°C and the optimized melting temperature for granite stone and borax systems was around 1400°C when comparing X-ray diffraction analysis (XRD) results. Phase transitions and thermal reactions of granite stone sludge systems were also investigated from thermal analysis using Thermogravimetric Analysis (TGA)/ Differential Scanning Calorimeter (DSC).

Effect of filler gradation on creep response of asphalt mix

Smaller fractions of aggregates in asphalt mix are known as fillers. Although substantial literature dealing with, (i) the response of asphalt mastic due to load and (ii) estimation of optimal quantity of filler for different types of fillers, is available, literature on the effect of gradation of filler (derived from same natural source) on the response of asphalt mix is rather scanty. This issue has been explored in the present work. In this study, granite stone dust is used as filler. Three different gradations of filler (G1, G2 and G3) are prepared from natural filler (G0) by varying the size proportions of the filler particles. Indirect tensile strength (IDT) and creep tests are conducted on filler–binder mix and also on asphalt mix. The results show that gradation of filler affects the creep response of the filler–binder mix as well as that of the asphalt mix. It is observed that the IDT value varies from about 555 to 665 kPa across the four fillers (G0, G1, G2 and G3) for 5.5% of asphalt content. Likewise, the deformation value in the creep test (with 500N creep loading for 120s) varies from about 0.26–1.09 mm across the four fillers. The average inter-particle distance between the filler particles is hypothesised as a possible indicator so as to explain the variations observed in the test results.

Thermal stress-induced microcracking in building granite

Microcracking induced by wide fluctuations in temperature affects granite quality and durability, making the stone more vulnerable to decay. Determining the extent of that effect is not always straightforward, however, given the excellent durability of these materials.Four types of construction granite quarried in the region of Madrid, Spain, and frequently used in both the built heritage and in de novo construction (Alpedrete, Cadalso de los Vidrios, Colmenar Viejo and Zarzalejo) were exposed to 42 thermal cycles (105–20°C; UNE-EN, 14066, 2003). Petrographic and petrophysical properties were analysed using both destructive and non-destructive techniques. Microcracking generated in the granite stones by 42 thermal cycles had barely any impact on their petrophysical properties, which are the parameters normally assessed to establish material quality and durability. Their petrographic properties, which are not generally assessed in this type of studies, were affected, however. This study contends that petrographic analysis is needed to objectively quantify the actual quality and durability of the most highly resistant materials when petrophysical studies are inconclusive. Petrographic and fluorescence microscopy, along with fractography, are among the most prominent techniques for petrographic exploration. Thanks to the deployment of these techniques, mineral microcracking could be monitored throughout the present tests conducted.The microscopic findings revealed substantial micro-textural and microstructural change in and around the granite minerals, which play a prominent role in decay. The findings showed that pre-existing microcracks coalesced and generated further microcracking as decay progressed. Microcracking was most intense in Zarzalejo granite due to its textural characteristics determined by its high feldspar content. Microscopic observation revealed that the microstructure of feldspar minerals, with their crystallographic anisotropies and secondary mineral phases, favoured microcrack development. Zarzalejo granite exhibited lower quality and durability than Colmenar Viejo and Cadalso de los Vidrios granites, which were more resistant to heat treatment.

Effect of a Pipe Number on The Heat Transfer Rate for a Granite Stone Absorber Solar Collector

Effect of a Pipe Number on The Heat Transfer Rate for a Granite Stone Absorber Solar Collector

Geometric indices to quantify textures irregularity of stone masonry walls

This paper aims at developing a general methodology supported by quantifiable geometric indices to classify the irregularity of stone masonry walls by direct observation of the elevation texture. This classification is based on indicators proposed in procedures developed in Italy, complemented with new tools and criteria. In particular, the evaluation of the geometric irregularity is done through a set of partial indices that consider the stones’ shape, size and their organization along horizontal and vertical alignments. The methodology was applied to twenty-four granitic stone masonry walls selected from old buildings located at Porto city centre, in Portugal, and a classification is proposed based on irregularity levels graded according to the ranges of the different indices found for these walls.

PRODUCTION OF ARTIFICIAL STONE SLABS USING WASTE GRANITE AND MARBLE STONE SLUDGE SAMPLES

In this work, the waste stone sludge obtained from the granite and marble stone processing factories was used for the manufacture of artificial stones using vibratory compaction in a vacuum environment. The results obtained showed that water absorption and density increased, and the flexure, compressive, and tensile strengths decreased with increase in the content of the waste stone sludge. These results also demonstrated that by combining 50% of stone sludge, 12% of ground quartz, 25% of waste glass, and 13% of resin at a compaction pressure of 12 MPa, a vibration frequency of 30 Hz, and vacuum conditions at 50 mm Hg, artificial stone slabs with a water absorption less than 0.64, a density less than 2.68, a flexure strength more than 45 MPa, a compressive strength more than 90 MPa, and a tensile strength more than 35 MPa can be obtained. The artificial stone slabs obtained in this research work had good density and water absorption, and flexure, compressive, and tensile strengths compared to the natural stones, and thus they can be regarded as the ideal construction materials for covering walls or paving floors.

Evaluation of Asphalt Mix with Dolomite Aggregates for Wearing Layer

Bearing capacity and durability of road pavement structure depends on design solution, transport loads, climate, materials and construction quality. But the main factors are selected materials for road pavement structure and their properties. Typically, there are selected high quality aggregates for asphalt wearing layer of heavy duty pavement. In Lithuania, granite aggregates are often used for asphalt wearing layer, but this magmatic rock is imported from other countries. Dolomite is one of the most available sedimentary rocks in Lithuania and quarries contain hundreds million tons of this material. Either, high quality dolomite is produced applying special extraction technology, and the mechanical properties of this material are similar to granite. The aim of this research is to evaluate high quality dolomite as aggregates for asphalt wearing layer and to design rut resistant asphalt mix with dolomite aggregates. Test results showed good bitumen-aggregate adhesion properties. There were designed asphalt concrete (AC) mixes using granite and high quality dolomite aggregates and stone mastic asphalt (SMA) mixes using high quality dolomite aggregates based on fundamental properties in accordance to standard EN 13108-1 and EN 13108-5. Resistance to permanent deformation of asphalt mixes is achieved by designing coarser gradation mixes with higher content of air voids (3–4%) comparing to traditional asphalt mixes for wearing layer (2–4%). Designed asphalt mixes were tested using empirical and performance based tests, which showed promising results for asphalt mixes with high quality dolomite aggregates.

The Role of Edge-Concentrated Wear in Impact-Abrasion Testing

The role of edge wear was studied in impact-abrasion testing conditions with an impeller-tumbler type test device. Three steels with different mechanical properties were tested at 30° and 90° sample angles using natural granite stone as abrasive particles. The edge and planar (inner) areas were carefully exposed to the same conditions by using tightly fitted two-part samples to obtain relevant information about the differences in their wear behavior. The role of edge-concentrated wear was dominant in all materials, and the edge wear rate was several times higher than the wear rate of the inner parts of the specimens. The difference in wear rate was particularly large in short tests and with the 90° sample angle. However, the dominance of the edge-concentrated wear decreased as the test duration became longer. The wear mechanism was largely microfatigue in all materials, but the samples tested at the 30° sample angle showed more microcutting in comparison to the 90° samples. Moreover, the role of microcutting was higher in the wear of the edge parts than in the inner parts.

Strength Assessment of Concrete Cubes Containing Variable Mixtures of Portland Cement and Granite Dust of the Maddhapara Mine, NW Bangladesh

Granite dust is a waste material which is produced during crushing and grinding process of granite stone. The annual production rate of the Maddhapara Granite Mine is 1.65 million metric tons from the underground mine. It has been estimated that the average weight of the granite dust is about 10% of the total weight of the annually produced granite rock from the Maddhapara Mine. The granite dust in Bangladesh is negligible in construction works, although it has a huge potential for the replacement of natural fine aggregates. The granite dust of Maddhapara Mine may be an alternative to natural sand for construction works. The present research highlights the compressive strength behavior of concrete cubes containing granite dust as a fine aggregate associated with variable mixtures of Portland cement. The three stages of working methods have been applied in the present research work, like- (i) collection of samples from the field, (ii) grain size analysis, and (iii) compressive strength test of concrete cubes with different curing periods of 7, 14 and 28 days. Compressive strength test was carried out on five concrete cubes with grades of M5, M10, M15, M20, M25. The grain size distribution curve as well as Cu (9.88) and Cc (0.671) values reveal that the Maddhapara granite dust is classified as well graded sand that can be enhanced high compressibility and shear strength. The compressive strength values of 14 and 28 days curing periods reveal that the M15 grade is a good quality option because of its high compressive strength associated with reasonable amount of cement and granite dust ratio. From the technical points of view, it can be focused that the Maddhapara granite dust can be used in various purposes. Appropriate utilization of granite dust would not only save the large amount of construction cost, but also would open a new window for the economic sector of the mine.