Stone Mixture Research Articles

Modification of Lime‐Fly Ash‐Crushed Stone with Phosphogypsum for Road Base

In order to increase the recycling of phosphogypsum waste, this study explored the feasibility of using phosphogypsum to replace some of the lime and aggregate in the lime‐fly ash‐crushed stone mixture which is a widely used road base material in China. For this purpose, compaction, compressive strength, composition structures, wetting‐drying cycle tests, and shrinkage tests were carried out on the lime‐fly ash‐phosphogypsum‐crushed stone composite to investigate its performance. The results indicate that lime‐fly ash‐crushed stone modified with phosphogypsum has the required strength of the road base material and favourable performances in environment (wetting‐drying cycle) stability. The image processing analysis and shrinkage tests demonstrated that phosphogypsum can significantly improve the compactness and shrinkage performance of lime‐fly ash‐crushed stone mixture. A suitable content of phosphogypsum and a reasonable content of fine aggregate are conducive to improving the roadway engineering properties (i.e., decreasing shrinkage cracks and increasing compressive strength) of lime‐fly ash‐phosphogypsum‐crushed stone composites.

Research on Design Indicators for Graded Crushed Stone Mixture Based on Vibration Molding Method

The asphalt pavement easily shows the diseases like cracking, rutting, and structural water damage during the early service life in Fujian province for the complex effects of very high temperature, easily rainy climatic condition, and high‐frequency heavy loading. However, the corresponding studies and strategies are still rare. Herein, in order to study the relationship of compaction methods on the stress‐strain characteristics and shear strength of graded crushed stone mixtures, 11 kinds of typical graded crushed stone mixtures, which were taken from the five different expressways under construction in Fujian Province, were molded by both the modified vibration compaction and modified Proctor compaction. The results indicate that the modified vibration molding method matches much better with the compaction of practical projects and can be used to evaluate the performance of graded crushed stone mixtures. Further, the performance indexes got by the modified vibration compaction and the modified Proctor compaction have strong correlations. Therefore, based on the modified vibration compaction, the guidelines for standardized mix design of graded crushed stone mixture in Fujian province are proposed: the resilient modulus of 300 MPa and the deformation rate of 10–8 in the dynamic triaxial test are used as the performance indicators of the bearing capacity and the antideformation ability; the shear strength of 400 kPa in the static triaxial test is used as the performance indicators of the shear failure resistance. Besides, most limestone mixtures perform well and have the advantages of good resistance to permanent deformation and shear resistance.

Flexural Behavior of Cement Concrete Beams Containing Recycled Waste Glass as Coarse Aggregate

Waste glass can be a non-biodegradable substance and at this its drop on a land that becomes a very world organisation property selection. To look out a far higher response to cut back the ecological issues caused by disposable of waste glass is used as concrete manufacturing. Recycled glass as coarse mixture is used to prepare for various grade of concrete mix like M 20, M 40 and M 60 as an alternate for typical crushed stone for creating concrete. The physical and chemical characterize of recycled waste glass coarse mixture is examine and note the similarities with typical crushed stone aggregate. For each mix to hunt out out the mechanical strength of control concrete and RWGCA mixture concrete. Six numbers of cube size 100 × a hundred × 100 metric linear unit are cast. To check flexural behaviour, a hundred twenty five × two hundred × 1100 metric linear unit size of the beams are cast. Beam sections are created as below strengthened sections. For on prime of grade mix, three beams are created with typical crushed stone mixture & alternative 3 beams are created with RWG coarse mixture. All the beams are tested under two point loading. The flexural behaviour of beams are obtained. ANSYS software is used for finite element modeling and the results of experimental values are compared with ANSYS modeling.

Adsorption of pharmaceutical residues on adsorbents prepared from olive stones using mixture design of experiments model.

In this work, inexpensive and easily available olive stone (OS) waste was used as the source material to prepare activated carbons (ACs) by chemical activation with phosphoric acid and zinc chloride. The mixture design of experiments (MDOE) method was applied to study the effect of the composition of the mixture of unmodified olive stones (UOS) and ACs prepared from olive stones activated with ZnCl2 (ACOS ZnCl2) and H3PO4 (ACOS H3PO4) on the absorption of pharmaceutical residues. The adsorbed tetracycline (TC) amounts at equilibrium predicted from the model equation developed using Microsoft Excel were found to be in good agreement with the experimental values (R2 = 0.999). Based on the results of the model, the amount of TC removed increased as the proportion of ACOS H3PO4 in the adsorbent mixture increased and the highest amount of TC adsorbed was obtained with an adsorbent made up entirely of ACOS H3PO4. Separate adsorption tests for sulfamethazine (SMT) and amoxicillin (AMX) on ACOS H3PO4 showed that SMT was adsorbed best (189.81 mg/g), followed by TC (183.11 mg/g) then AMX (155.69 mg/g). However, when these molecules were present together in the same solution, it was TC that adsorbed best, followed by SMT then AMX. In addition to this, the sorption process studied was best described by a pseudo-first-order model and it was the Langmuir model that satisfactorily described the equilibrium data.

Application Of Lime Marl In The Formation Of Areal Groundwater Mounds Of The Imereti Lowlands

The article deals with the experience of applying lime marl in the formation of engineering protection embankments on the unique territory of the Imereti Lowlands in terms of its engineering and geological conditions. It is known that this site became a place for construction of various facilities for carrying out a wide complex of sports actions of the Olympic Games-2014 (coastal cluster). It is shown how under complex engineering and geological conditions, engineering protection measures were realized. On the support sites - an experiment on the use of local carbonate material for backfilling of soil embankments of engineering protection was executed. Three versions of the backfilling of carbonate soil were used. It is established that the crushed stone mixture of lime marl in the course of 1-2 years of operation of the engineering protection structure increased the parameters of its mechanical properties due to natural cementing ability. In the case where the crushed stone mixture of lime marl was above the groundwater level, calcium oxide contributed to the strengthening of the rock, releasing the cementing layers of the compound. This confirmed the opening of the contact of the underlying soils and soils of engineering protection, as well as the absence of surface deformation in these areas during the operation of the erected structures. In the areas of quarters where the crushed stone mixture of lime marl was flooded as a result of malfunctions of the drainage system, surface settlements and deformations of the structures occurred.

Influence of Stone Content on Soil Hydraulic Properties: Experimental Investigation and Test of Existing Model Concepts

Core Ideas Unsaturated hydraulic conductivity of stony soils was determined in medium moisture range. Evaporation method works for stony soils, even if stone contents are high. Theoretical scaling models showed a good agreement with measurements for moderate stone contents. Model results and measurements differ markedly for soils with high stone contents. Studying the role of gravel, stones, or rock fragments on effective soil hydraulic properties (SHPs) is crucial for understanding and predicting soil water processes such as evaporation, redistribution, and water and solute transport through soils containing significant amounts of coarse inclusions. We conducted a laboratory study in which we investigated the effect of stones on the water retention and unsaturated hydraulic conductivity curves of soil–stone mixtures. Stony soils were created by packing predefined masses of soil particles (sand and sandy loam) with diameters <2 mm and crushed basalt (2–5 and 7–15 mm). The resulting mixtures ranged from 0 to 40% (v/v) stone content. The SHPs were determined with the simplified evaporation method. The measurements yielded plausible water retention and hydraulic conductivity curves across a wide moisture range. Results qualitatively showed the expected dependencies of SHPs on volumetric stone content, characterized by a reduction of soil water content and hydraulic conductivity across the whole pressure head range. Measured data suggested that coarse inclusions in soil tend to widen the effective pore‐size distribution. Prediction of SHPs of the stony soils, performed by fitting a flexible SHP model to the data of the background soil and scaling it with approaches from the literature, worked well for low stone contents. However, for volumetric stone contents of 25 and 40%, measured SHPs differed substantially from the properties predicted by simple scaling models.

Soluble Salt in Municipal Solid-Waste Incinerator Bottom Ash and Its Effect on the Performance of Cement-Stabilized Materials

The contents of soluble salts, including chloride and sulfate, were tested to use municipal solid-waste incinerator bottom ash (IBA) in cement-stabilized materials for roadbase. In addition, the effects of soluble salts on the strength properties of cement stabilized IBA and crushed stone mixture were analyzed by applying unconfined compressive and splitting strength tests, respectively. Moreover, the deformation properties of the mixture were analyzed by applying dry and temperature shrink tests, respectively. In addition, the microscopic mechanism of chloride and sulfate on the mixture was analyzed by using micro-test methods. Results show that the average contents of chloride and sulfate in IBA are 0.57% and 1.01%, respectively. The strength of the mixture that contains 30% IBA greatly decreases when the contents of chloride and sulfate in IBA are higher than 1.67% and 2.00%, respectively. The dry and temperature shrinkage deformations of the mixture greatly increase when the contents of chloride and sulfate are higher than 0.67% and 1.00%, respectively. Water treatment reduces the soluble salt content of IBA. Unlike the control mixture, the strength properties of the mixture that contained IBA with water treatment shows no remarkable difference, whereas the short and temperature shrinkage deformations increase and decrease, respectively. Microscopic analysis shows that Cl- reacts with cement hydration products to produce Friedel salts, and the amount of hydration products increases in the mixture due to the addition of chloride and sulfate. However, some cement particles are not hydrated when the Na2SO4 content is 1.0%. The content of soluble salts in IBA should be limited to ensure the performance of the mixture.

The antibacterial activity of certain disinfectant solutions incorporated into stone mixture

Cross infection control is a way of life and it was realized that a radical changes inthe way of work in the dental clinic and laboratories would detect considerable revisesof traditional working patterns. Disinfection of dental stone cast by incorporation ofChlorhexidine gluconate CHX, Sodium hypochlorite and Madacide 11 separately in aconcentration of (0.5 , 0.5 , full strength) respectively according to the manufacturerinstructions and testing their activity against S.aureus,  -haemolytic streptococcuspneumonia, pseudomonas aeruginosa and E. coli was performed. 5 trials were donefor each disinfectant solution and control (distilled water).The result showed that all the disinfectant solutions showed significant reductionof microbial growth in comparison with the control. Sodium hypochlorite sterilizedental stone cast followed by CHX.Sodium hypochlorite gave negative result for allthe tested microorganisms in all the trials followed by chlorhoxidine gluconatesolutions .Disinfection of stone cast is among recommended methods in infectioncontrol.Sodium hypochlorite was the best among the tested disinfected solutions.

Evaluation of the Functional Impression Technique with Various Impression Materials on the Surface Topography of Dental Stone Casts and Their Effect on Retention

Background: The accuracy of the final prosthesis is affected by the final impression technique and master cast production. The aim of the present study was to evaluate the effect of the functional impression technique with various impression materials on the surface characteristic of dental stone casts and their clinical effect on the retention of complete dentures. Method: Specimens of three impression materials/stone casts were fabricated. The specimens of the impression materials/stone casts were divided into three equal groups (I, II, and III). The impression materials used were as follows: tissue conditioner group (I), zinc oxide (ZEO) (group II) and poly (vinyl siloxane) (PVS) (group III). Cylindrical split aluminium moulds were designed to receive the impression materials and the stone mixture. The surface roughness of the stone cast specimens of the three groups (I, II, and III) was measured with a surface profilometer and analyzed by a scanning electron microscope. A clinical study included five severely resorbed mandibular edentulous alveolar ridges and edentulous maxillary arches. Each subject received three heat-cured acrylic resin dentures, fabricated using the functional impression technique. The three dentures were identical except for the different impression materials used from Groups I, II and III. The retentive force of each denture for each subject was measured. Result: The results of this study revealed that the mean value of surface roughness of the stone cast surface of group I was higher than group II and group III. A statistically significant difference was observed in surface roughness and the retentive dislodging force between the three studied groups. Although using a tissue conditioner as a functional impression material led to a high level of surface roughness and good retention, it could not produce the same smooth surface quality of PVS or ZEO. These data were supported by SEM analysis. The complete dentures for these patients require important oral and denture hygiene care. Conclusion: Complete dentures made using functional impression technique with PVC as a final impression material are more comfortable, retentive and stable.

The influence of different immersion time intervals and disinfection of tissue conditioner functional impression materials on the surface roughness of stone cast

Tissue conditioners are used as a functional impression material, to re-condition the denture-bearing mucosa abused by ill-fitting dentures and as a temporary lining material for immediate dentures. The immersion of tissue conditioners in disinfectant prior to pouring the impression can significantly affect the properties of dental stone depending on the duration of immersion. The present study aims to evaluate the effect of immersion time of tissue conditioner on the surface roughness of dental stone. Thirty specimens of tissue conditioner stone casts were prepared on cylindrical split aluminum with a lower hollow ring designed to receive the tissue conditioner and an upper ring adjusted to receive the stone mix. The thirty specimens of tissue conditioner were divided into 3 equal groups of 10 specimens according to the storage period (1hr, 24hrs and 48hrs). The three groups were subdivided into two subgroups: subgroup (a) 2% chlorhexidine (CHX) solution were sprayed on the surface of tissue conditioner specimens prior to pouring with dental stone materials while the other subgroup (b) specimens were poured with dental stone but without using (CHX) disinfection. The dental stone mixture was poured into molds and stored at room temperature for 60 minutes. The stone casts were then separated from the tissue conditioner and the surface roughness values of these dental stone casts was determined. Our results revealed a significant higher means values of surface roughness of groups (IIa and IIIa) when chlorhexidine was used compared to groups (IIb and IIIb). Comparison between subgroups (a and b) showed a statistical significance between (IIa and IIb) and (IIIa and IIIb). Based on the obtained results it can be concluded that the optimum time for using tissue conditioner as functional impression is from 24 to 48 hours after immersion. The use of 2% chlorhexidine solution disinfectant had adverse effect on surface roughness of dental stone.

Recurrent Pyogenic Cholangitis: A Comparison Between Asians and a Non-Asian at a Metropolitan Hospital in the United States

Recurrent pyogenic cholangitis (RPC) is a condition characterized by intrahepatic stone formation of unknown etiology causing biliary obstruction and recurrent cholangitis. Almost exclusively reported in East Asia, there is increasing incidence in the West due to human migration. Rarely, sporadic cases have been reported in people with no links to East Asia. We report our experience with 5 patients with RPC (4 East Asians and one Caucasian) managed at our institution in the past decade. We compared the Caucasian female with no travel history or links to East Asia with 4 East Asian females, all of whom presented with features of cholangitis comprising fever, right upper quadrant pain, and jaundice. All had a prior history of cholecystectomy with recurrent post-cholecystectomy cholangitis. Diagnosis was made from history and characteristic findings on abdominal computerized tomography (CT) and endoscopic retrograde cholangiopancreatography (ERCP). Individual clinical, radiological, and interventional details are described in Tables 1 and 2. All 4 East Asian patients had significant dilation of the left intrahepatic duct (IHD), common hepatic duct (CHD), and common bile duct (CBD); in addition to pigment stones and benign biliary stricture. In contrast, the Caucasian patient had a mixture of pigment and cholesterol stones, less intrahepatic dilation, and no biliary stricture or liver atrophy. An interdisciplinary approach was employed in management. All 4 East Asian patients underwent surgery (Table 2) with the goal of resecting the area of recurrent infection, biliary stasis, and hepatic atrophy. The Caucasian patient refused surgery and had one more episode of cholangitis requiring repeat ERCP and stone extraction, while the East Asians who underwent surgical management had a favorable outcome with no further episodes of cholangitis. Increased awareness and timely diagnosis is needed for early involvement of a multi-disciplinary team in the management of patients with RPC. Regular surveillance is crucial as there is a high chance for stone recurrence. Repeated attacks can lead to progressive damage to the bile ducts and liver parenchyma resulting in liver abscesses, cirrhosis, and atrophy; along with increased risk of cholangiocarcinoma and death due to sepsis and liver failure. Resection of the affected hepato-biliary segments has been shown to lead to better quality of life, lower rates of secondary biliary cirrhosis, cholangiocarcinoma, and mortality.Table: Table. Clinical CharacteristicsTable: Table. Radiological and Pathological Findings

Application of Non-Destructive Methods for the Determination of Microstructural Parameters of Recycled Asphalt Concrete in Track Bed

The extent of the use of asphalt concrete in track bed layers is minimal in contrast to the application of granular materials mostly represented by coarse/fine crushed stone mixture. This article summarizes advantages and disadvantages of the use of asphalt concrete in the track bed construction and provides relevant literature research. The main part of this article focuses on the application of recycled asphalt concrete (so called R-material) in the track bed layer and its following non-destructive X-ray Micro Computed Tomography Method (Micro-CT) for the description of its structural parameters. The contribution of this research is based on the evaluation of the air void and soluble binder content of chosen recycled asphalt concrete. First, it was obtained from laboratory geotechnical models of a railway track, and then from the following implementation in a trial section of an operating railway track. The conclusion contains results of the R-material practical application and findings from Micro-CT.

Self-Healing Performance of PVA-ECC-Stabilized Crushed Stone Mixture

AbstractFor improving the crack resistance of the semi-rigid base of an asphalt pavement and self-healing property to the base, the main materials (cement, fly ash, quartz sand, and polyvinyl alcoh...

Evaluation of area- and volume-based gradations of sand-crushed stone mixture by 2D images

Ballast fouling is a challenging issue in ballasted railway tracks due to frequent maintenance works. At present, sieve analysis is conducted to obtain the gradation curve of fresh and fouled ballasts at laboratories. The investigation time is quite long since it requires a sampling. The information obtained from sieve analysis are not sufficient to propose appropriate maintenance plans since it does not produce shape characteristics of the particles properly. In this research, area- and volume-based gradation curves of fresh and fouled ballasts, simulated by laboratory-scale particles, were studied using an image analysis method. A simple method was proposed to obtain the volume-based gradation curve by 2D images. This method can be practised as an in-situ test method since it needs only a camera and a computer. The results suggest that the grain size should be defined appropriately according to the shape assigned for the particles. It was also found that area-based gradation curve produced by an ellipse shape for the crushed stone particles match sieve analysis closer than circle and rectangle shapes. The results also indicate that area-based gradation match sieve analysis closer than number- and volume-based gradations for the crushed stone particles. It was also found that the volume-based gradation curves evaluated by parallel and diagonal passing overestimate and underestimate respectively its grain size compared to sieve analysis. The gradation curve evaluated by an equivalent passing with a grain size correction factor match the sieve analysis for crushed stone, sand and sand-crushed stone samples. The image analysis results also indicate that the crushed stone particles are more angular than sand particles, which is important in numerical analysis to simulate fresh and fouled ballasts.

Structural analysis of lunar subsurface with Chang׳E-3 lunar penetrating radar

Geological structure of the subsurface of the Moon provides valuable information on lunar evolution. Recently, Chang׳E-3 has utilized lunar penetrating radar (LPR), which is equipped on the lunar rover named as Yutu, to detect the lunar geological structure in Northern Imbrium (44.1260N, 19.5014W) for the first time. As an in situ detector, Chang׳E-3 LPR has relative higher horizontal and vertical resolution and less clutter impact compared to spaceborne radars and earth-based radars.In this work, we analyze the LPR data at 500MHz transmission frequency to obtain the shallow subsurface structure of the landing area of Chang׳E-3 in Mare Imbrium. Filter method and amplitude recovery algorithms are utilized to alleviate the adverse effects of environment and system noises and compensate the amplitude losses during signal propagation. Based on the processed radar image, we observe numerous diffraction hyperbolae, which may be caused by discrete reflectors beneath the lunar surface. Hyperbolae fitting method is utilized to reverse the average dielectric constant to certain depth (ε¯). Overall, the estimated ε¯ increases with the depth and ε¯ could be classified into three categories. Average ε¯ of each category is 2.47, 3.40 and 6.16, respectively. Because of the large gap between the values of ε¯ of neighboring categories, we speculate a three-layered structure of the shallow surface of LPR exploration region.One possible geological picture of the speculated three-layered structure is presented as follows. The top layer is weathered layer of ejecta blanket with its average thickness and bound on error is 0.95±0.02m. The second layer is the ejecta blanket of the nearby impact crater, and the corresponding average thickness is about 2.30±0.07m, which is in good agreement with the two primary models of ejecta blanket thickness as a function of distance from the crater center. The third layer is regarded as a mixture of stones and soil. The echoes below the third layer are in the same magnitude as the noises, which may indicate that the fourth layer, if it exists, is uniform (no clear reflector) and its thickness is beyond the detection limit of LPR. Hence, we infer the fourth layer is a basalt layer.

In situ study of stones adorning a silver Torah shield using portable Raman spectrometers

A silver Torah shield fitted with a set of precious stones and glass imitations crafted in Poland in the first half of the 19th century was investigated using two of the currently distributed portable and relatively low‐cost Raman spectrometers in situ at the Jewish Museum in Prague. Observed Raman peaks corresponded well (+/− 3 cm−1) to the reference values. The hand‐held instruments operated at 785‐ and 532‐nm laser excitations showed good performance in the fast and unambiguous identification of nearly 60 stones which were fitted on the shield: one blue aquamarine, three purple amethysts, thirteen red garnets (all classified as high‐percentage almandines), three white pearls, fifteen pieces of red coral and five chalcedonies (one white and four red). All of the other stones were identified as colored glass. The rather chaotic mixture of stones of various colors, cuts and sizes and the total volume of imitation glass support the theory that the mounted stones were gathered from Jewish households and donated for the adornment of the shield. The common portable Raman instruments represent an ideal tool for the quick and accurate identification of gemstones mounted in historical artifacts in situ in the framework of museum or collection sites in a non‐destructive way. Copyright © 2014 John Wiley & Sons, Ltd.

The oldest anatomical handmade skull of the world c. 1508: 'the ugliness of growing old' attributed to Leonardo da Vinci.

The author discusses a previously unknown early sixteenth-century renaissance handmade anatomical miniature skull. The small, naturalistic skull made from an agate (calcedonia) stone mixture (mistioni) shows remarkable osteologic details. Dr. Saban was the first to link the skull to Leonardo. The three-dimensional perspective of and the search for the senso comune are discussed. Anatomical errors both in the drawings of Leonardo and this skull are presented. The article ends with the issue of physiognomy, his grotesque faces, the Perspective Communis and his experimenting c.1508 with the stone mixture and the human skull. Evidence, including the Italian scale based on Crazie and Braccia, chemical analysis leading to a mine in Volterra and Leonardo's search for the soul in the skull are presented. Written references in the inventory of Salai (1524), the inventory of the Villa Riposo (Raffaello Borghini 1584) and Don Ambrogio Mazenta (1635) are reviewed. The author attributes the skull c.1508 to Leonardo da Vinci.

A deformation mechanism of hard metal surrounded by soft metal during roll forming.

It is interesting to imagine what would happen when a mixture of soft-boiled eggs and stones is deformed together. A foil made of pure Ti is stronger than that made of Cu. When a composite Cu/Ti foil deforms, the harder Ti will penetrate into the softer Cu in the convex shapes according to previously reported results. In this paper, we describe the fabrication of multilayer Cu/Ti foils by the roll bonding technique and report our observations. The experimental results lead us to propose a new deformation mechanism for a hard metal surrounded by a soft metal during rolling of a laminated foil, particularly when the thickness of hard metal foil (Ti, 25 μm) is much less than that of the soft metal foil (Cu, 300 μm). Transmission Electron Microscope (TEM) imaging results show that the hard metal penetrates into the soft metal in the form of concave protrusions. Finite element simulations of the rolling process of a Cu/Ti/Cu composite foil are described. Finally, we focus on an analysis of the deformation mechanism of Ti foils and its effects on grain refinement, and propose a grain refinement mechanism from the inside to the outside of the laminates during rolling.

Geomaterials under the microscope: a color guide: building stone, roofing slate, aggregate, concrete, mortar, plaster, bricks, ceramics, and bituminous mixtures

Geomaterials under the microscope: a color guide: building stone, roofing slate, aggregate, concrete, mortar, plaster, bricks, ceramics, and bituminous mixtures

Cracks Resisting Mechanism Analysis of Large Stone Mixture Base Based on Mechanics Calculations

In order to study the cracks resisting mechanism of large stone asphalt mixture base, a multi-layer elastic theory program was used to calculate the loading stress in different pavement structures. Then a Finite Element model was established based on a twinkling heat conduct hypothesis to calculate temperature stress and strain of pavement structure when temperature dropped. Finally, the stress and strain of all the structural layers was calculated considering the coupling effect of loading and temperature. It is found that temperature stress which is caused by temperate quick dropped is far more lager than loading stress cause by standard loading, while considering the co-effect of vehicle loading and temperature quickly dropped. Thus it is revealed that cracking in pavement is mainly caused by temperature quickly dropped. By contrast, it is found that pavement stress and strain caused by loading and temperature of the structure with asphalt macadam mixture (ATB30) base are less than that of the conventional semi-rigid pavement. Finally, an asphalt macadam mixture base applied in asphalt pavement structure is believed to be an efficient way in reducing asphalt pavement cracking.