Aggregate Sources Research Articles

A systematic review of the extant literature on the Tanzanian e-government services for economic development

This paper investigates the existing Tanzanian e-government services for economic development through a systematic review of the literature. The main objective is to examine researchers’ articles on e-government services towards achieving the Tanzanian economic growth as well as the current issues and trends on e-government globally. Specifically, this study aims to answer three research questions on: what are the functional e-government services in Tanzania? What is the level of Tanzanian e-government service performance? And what are the factors influencing Tanzanian e-government service performance for economic development? A systematic literature search was conducted on four aggregate data sources, which included Google Scholar, ResearchGate, CORE, and Refseek. A combination of search key terms was employed to obtain the data sources from 2015 to 2022. One hundred and five articles were found by the combined search and screened, resulting to eighteen articles that were recommended for the study. Content and Microsoft Excel computer application were used to analyse the screened data sources. The findings reveal that, a number of functional services is offered and considered potential for revenue collection and contribute to the nation's economic development. Nevertheless, Tanzania has improved and dynamically advanced to the transaction level of e-government implementation where the majority of the citizens interact for services and information. However, factors related to the activeness of the platforms, accessibility, usability, infrastructure, security issues, privacy, and technical support services among others, were identified to influence the performance of Tanzanian e-government services and thus call attention to the government in addressing these issues.

Unsupervised multi-source domain adaptation via contrastive learning for EEG classification

Individual differences in electroencephalography (EEG) present significant challenges for subject-independent EEG classification in brain–computer interfaces (BCIs). Existing domain adaptation methods often address individual differences by merging all source domains indistinguishably into a single source and aligning features between this aggregate source and the target domain. Neglecting the relationships between different source domains would hinder the model’s adaptability and generalization. Therefore, we propose a method called Contrastive Learning-based Unsupervised multi-source Domain Adaptation (CLUDA) for learning subject-independent representations in motor imagery. Our method not only aligns the conditional distributions of each source domain with the target domain but also reduces discrepancies among the source domains using contrastive learning, thus learning more generalized domain-invariant representations. Specifically, CLUDA effectively eliminates semantic variances by maximizing the similarity between positive pairs (same class) and minimizing the similarity between negative pairs (different classes) across subjects. Finally, we validated CLUDA on four motor imagery datasets and consistently achieved state-of-the-art performance.

Laser Metal Printing from Nanoparticles Prepared by a Gas Aggregation Source

Laser Metal Printing from Nanoparticles Prepared by a Gas Aggregation Source

Assessing cracking resistance and threshold limits of bituminous mixtures with IDEAL-CT and predictive modeling techniques

This paper presents a comprehensive study to establish the threshold limit of CTIndex for the Marshall mixes. The study also aims to assess the impact of different design factors on the cracking resistance of bituminous mixtures using the Indirect Tensile Asphalt Cracking Test (IDEAL-CT) test. This study considers 2 different aggregate sources, 2 different gradations, 5 different types of Design Aggregate Gradation (DAG), 3 binder types, and 5 levels of compactive effort. The test results show that higher cracking resistance can be achieved using a smaller nominal maximum size of the aggregate (NMAS), finer gradation, modified binder, and decreased compactive effort with aggregates having low abrasion and absorptive characteristics. This study also comprehends the influence of volumetric parameters of the bituminous mixes on fracture resistance. It was found that at a particular Optimum Binder Content (OBC), higher bulk specific gravity of the compacted specimen (Gmb) and voids filled with asphalt (VFA) result in reduced CTIndex, specifying poor cracking performance. While higher air voids (AV) and voids in mineral aggregate (VMA) lead to increased CTIndex, indicating better-cracking resistance. Statistical analysis tools were used to evaluate the significance of the influential factors that are affecting the cracking potential of the mix. Different Machine learning models were also developed to predict CTIndex based on the design factors considered in the study. The random forest (RFR) model showed strong accuracy, reflected by low Mean Absolute Error (MAE=3.16), Mean Absolute Percentage Error (MAPE=9.57), Root Mean Square Error (RMSE=4.23), and a high coefficient of determination (R²=0.95) value, notifying a precise fit and reliable predictions. Additionally, a GUI has been also developed to enhance the practical usability of the model for wider usage. Further, the present study proposes the threshold value of CTIndex for the selection of crack-resistant bituminous mixtures. Moreover, the study investigated the correlation between laboratory and field compaction methods and validated the initial threshold specification of CTIndex for the Marshall mixes. Despite of the variations in different compaction methodologies and specimen thickness, a strong positive correlation (R² > 0.76) between laboratory and field cores of BC-1 and DBM-2 indicates that the performance criteria are adequate and justified.

To Analysis the Feasibility of Utilization of Modified Recycled Aggregate for Recycled Cement Bound Mixtures (A Review)

Construction and Demolition (C&D) wastes are generated through the demolition of concrete structures, and they are often discarded into the open area causing environmental problems. Various components such as bricks, concrete, steel, wood, etc., are generated through the demolition of structures. Perhaps the necessity of construction materials, especially aggregates, increases rapidly due to urbanization and industrialization. Construction activities mainly depend on natural resources as a source of raw materials, leading to ecological imbalance. So, the construction industries tend to depend on alternative materials as the source of aggregates in concrete production. Recycling C&D wastes and using them as aggregates will be a viable option to counteract the problems mentioned above. The recycled aggregates are broken fractions of C&D wastes with smeared cement particles adhered to on the surface of natural aggregates. In this study, recycled aggregates were collected from a 20-year- old demolished building at the university and recycled into fractions of 1.18 mm~2.36 mm and 10 mm~20 mm and replaced for both fine aggregates and coarse aggregates. However, the poor quality of recycled aggregates resulting from the presence of adhered mortar affects the properties of the concrete. Thus, this paper aims to improve the property of recycled aggregates through surface treatments. Though various treatments were developed either to remove or coat the adhered mortar surface on the recycled aggregates, this study uses microbes in conjunction with advanced mixing approach techniques to improve the quality of recycled aggregates and properties of the recycled aggregate concrete (RAC). This paper finds Feasibility of Utilization of Modified Recycled Aggregate in various construction work by study the different Literature review and articles

Marginal Aggregates: The Role of Clays.

Clays are components in the fine portion of aggregates, less than 75 microns in size (micro-fines), which are usually washed away when producing coarse or fine (manufactured sand) aggregates in quarries. When marginal sources of aggregates are being used, the content of this washed portion can be quite high, and there is an incentive to keep as much of it in the aggregate, including the clays. The present paper presents a comprehensive treatment of the role of clays in terms of the characterization of their composition and quantification of their effects on the rheological and mechanical properties of cementitious systems, as well as the means to mitigate deleterious influences. It is shown that the strategy for neutralizing the effect of micro-fines containing clays on increased water demand in concrete can be quantified in terms of the combination of their content in concrete and their nature as characterized by the methylene blue value (MBV); this is a more rational approach to considering their influence than their content in specific aggregates as specified in standards. The effect of low and medium MBV aggregates on the water requirement can be neutralized by lignosulfonates when their content in the concrete is below a threshold value of about 150 kg/m3; polycarboxylates (PC) are required at higher contents; for high MBV aggregates, a combination of PC and clay mitigating admixture (CMA) is required. It is also demonstrated that with proper treatment, such micro-fines can be turned into useful fillers, enhancing the strength of concrete and thus also serving as a means for reducing cement content.

Catalytic Heaters at Oil and Gas Sites May be a Significant yet Overlooked Seasonal Source of Methane Emissions.

Successful reduction of oil and gas sector methane emissions to meet near-zero intensity targets requires the identification and mitigation of all possible sources. One potentially important source is catalytic heaters, which have largely escaped attention in regulatory and mitigation efforts despite being ubiquitous at upstream production sites in cold climate regions. This study reports direct in situ measurements of the exhaust streams of 38 natural gas-fired catalytic heaters at upstream production sites in British Columbia, Canada. All heaters in the sample showed consistently poor methane conversion with mean destruction efficiencies of 61 ± 5% while releasing 235 [+31/-28] g of methane per cubic meter of fuel. Although individual units are generally small methane sources (mean of 0.28 ± 0.04 kg/h), their prevalence means they could represent 6% of the total provincial upstream methane inventory and as an aggregate methane source could be 5× more significant than abandoned wells. Notably, these heaters are seasonal sources whose emissions would be missed in measurement campaigns occurring solely in summer months. However, additional measurements from a small number of heat medium burners demonstrate that, where feasible, methane emissions can be reduced by approximately 425× by replacing catalytic heaters with centralized heat systems.

Overexpression of long noncoding RNA DUXAP8 inhibits ER-phagy through activating AKT/mTOR signaling and contributes to preeclampsia

Preeclampsia (PE) is a life-threatening pregnancy-specific complication with controversial mechanisms and no effective treatment except delivery is available. Currently, increasing researchers suggested that PE shares pathophysiologic features with protein misfolding/aggregation disorders, such as Alzheimer disease (AD). Evidences have proposed defective autophagy as a potential source of protein aggregation in PE. Endoplasmic reticulum-selective autophagy (ER-phagy) plays a critical role in clearing misfolded proteins and maintaining ER homeostasis. However, its roles in the molecular pathology of PE remain unclear. We found that lncRNA DUXAP8 was upregulated in preeclamptic placentae and significantly correlated with clinical indicators. DUXAP8 specifically binds to PCBP2 and inhibits its ubiquitination-mediated degradation, and decreased levels of PCBP2 reversed the activation effect of DUXAP8 overexpression on AKT/mTOR signaling pathway. Function experiments showed that DUXAP8 overexpression inhibited trophoblastic proliferation, migration, and invasion of HTR-8/SVneo and JAR cells. Moreover, pathological accumulation of swollen and lytic ER (endoplasmic reticulum) was observed in DUXAP8-overexpressed HTR8/SVneo cells and PE placental villus trophoblast cells, which suggesting that ER clearance ability is impaired. Further studies found that DUXAP8 overexpression impaired ER-phagy and caused protein aggregation medicated by reduced FAM134B and LC3II expression (key proteins involved in ER-phagy) via activating AKT/mTOR signaling pathway. The increased level of FAM134B significantly reversed the inhibitory effect of DUXAP8 overexpression on the proliferation, migration, and invasion of trophoblasts. In vivo, DUXAP8 overexpression through tail vein injection of adenovirus induced PE-like phenotypes in pregnant rats accompanied with activated AKT/mTOR signaling, decreased expression of FAM134B and LC3-II proteins and increased protein aggregation in placental tissues. Our study reveals the important role of lncRNA DUXAP8 in regulating trophoblast biological behaviors through FAM134B-mediated ER-phagy, providing a new theoretical basis for understanding the pathogenesis of PE.

N-Alkanes formed by methyl-methylene addition as a source of meteoritic aliphatics

Aliphatics prevail in asteroids, comets, meteorites and other bodies in our solar system. They are also found in the interstellar and circumstellar media both in gas-phase and in dust grains. Among aliphatics, linear alkanes (n-CnH2n+2) are known to survive in carbonaceous chondrites in hundreds to thousands of parts per billion, encompassing sequences from CH4 to n-C31H64. Despite being systematically detected, the mechanism responsible for their formation in meteorites has yet to be identified. Based on advanced laboratory astrochemistry simulations, we propose a gas-phase synthesis mechanism for n-alkanes starting from carbon and hydrogen under conditions of temperature and pressure that mimic those found in carbon-rich circumstellar envelopes. We characterize the analogs generated in a customized sputter gas aggregation source using a combination of atomically precise scanning tunneling microscopy, non-contact atomic force microscopy and ex-situ gas chromatography-mass spectrometry. Within the formed carbon nanostructures, we identify the presence of n-alkanes with sizes ranging from n-C8H18 to n-C32H66. Ab-initio calculations of formation free energies, kinetic barriers, and kinetic chemical network modelling lead us to propose a gas-phase growth mechanism for the formation of large n-alkanes based on methyl-methylene addition (MMA). In this process, methylene serves as both a reagent and a catalyst for carbon chain growth. Our study provides evidence of an aliphatic gas-phase synthesis mechanism around evolved stars and provides a potential explanation for its presence in interstellar dust and meteorites.

Tracing the vertical migration of exogenous cadmium in soil by seasonal freeze-thaw event using rare earth elements

Environmental behaviors of heavy metal in soil are strongly influenced by seasonal freeze-thaw events at the mid-high altitudes. However, the potential impact mechanisms of freeze-thaw cycles on the vertical migration of heavy metal are still poor understood. This study aimed to explore how exogenous cadmium (Cd) migrated and remained in soil during the in-situ seasonal freeze-thaw action using rare earth elements (REEs) as tracers. As a comparison, soil which was incubated in the controlled laboratory (25 °C) was employed. Although there was no statistically significant difference in the Cd levels of different soil depths under different treatments, the original aggregate sources of Cd in the 5–10 cm and 10–15 cm soil layers differed. From the distributions of REEs in soil profile, it can be known that Cd in the subsurface of field incubated soil was mainly from the breakdown of >0.50 mm aggregates, while it was mainly from the <0.106 mm aggregates for the laboratory incubated soil. Furthermore, the dissolved and colloidal Cd concentrations were 0.47 μg L−1 and 0.62 μg L−1 in the leachates from field incubated soil than those from control soil (0.21 μg L−1 and 0.43 μg L−1). Additionally, the colloid-associated Cd in the leachate under field condition was mainly from the breakdown of >0.25 mm aggregates and the direct migration of <0.106 mm aggregates, while it was the breakdown of >0.50 mm and the direct migration of <0.106 mm aggregates for the soil under laboratory condition. Our results for the first time provided insights into the fate of exogenous contaminants in seasonal frozen regions using the rare earth element tracing method.

Prediction on partial replacement of cement and coarse aggregate by zeolite powder and steel slag in high-performance concrete

High performance concrete is obtained by the inclusion of mineral admixtures like silica fume and fly ash in the concrete. The research explores the viability and performance of sustainable concrete by introducing zeolite powder as a partial substitute for cement and steel slag as a partial replacement for coarse aggregate in M-70 grade concrete. Zeolite powder, possessing pozzolanic properties, is a natural or synthetic aluminosilicate material, while steel slag is an industrial byproduct with potential as an alternative aggregate source. The main objective is to investigate the impact of zeolite powder and steel slag on the development of High-Performance Concrete (M-70) in accordance with Bureau of Indian standards. The formulation of high-performance concrete involved replacing 12.5%, 15%, and 17.5% of the cement with zeolite powder and varying the proportion of steel slag as a replacement for coarse aggregate (ranging from 30% to 55%). A comprehensive mechanical test was conducted on these specimens and compared with conventional concrete. Among the 19 mixes, the optimal combination was identified, incorporating 15% zeolite powder as a cement replacement and 45% steel slag as a coarse aggregate replacement, resulting in superior performance compared to conventional concrete. This mix was further studied for non-destructive testing, and microstructural analysis. Subsequently, the experimental results were compared with predicted outcomes using the Taguchi method. The close alignment between the values obtained experimentally and those predicted further validates the effectiveness of the optimized mix.

Properties of the ionization region in a magnetron plasma at gas-aggregation-source-relevant pressure regime explored using a global model

A global (volume averaged) model is developed for the ionization region (IR) of a gas aggregation source (GAS) plasma. The case of using argon gas and a copper target is considered. The model describes the densities of thermal and hot electrons, argon and copper ions, copper atoms and argon atoms in different excited states, the temperature of thermal electrons, the kinetic energies of the ions with which they bombard the target, the sheath width near the target cathode and the energy fluxes by different plasma species to a planar probe in the IR. Also, the fraction of input power is estimated which is dissipated to energize the thermal electrons in the IR. The gas discharge properties are analyzed for different pressures and discharge currents under conditions corresponding to the experimental conditions (Gauter et al 2018 J. Appl. Phys. 124 073301). The calculated pressure- and current-dependences for the GAS properties are used to explain the measured dependences for the deposition rate and the energy flux. It is found that the deposition rate increases with increasing discharge current because of the growth of currents of copper atoms and ions. With increasing pressure, the rate decreases due to drop of the densities of copper atoms and ions because of decreasing the kinetic energies of the ions with which they bombard the target. The model indicates that in the gas-aggregation-source relevant pressure regime, the energy flux by ions dominates over the energy fluxes of other plasma species.

Performance of foam concrete developed from construction and demolition waste

Unconscious industrialization, urbanization and consumption of natural resources pose a serious threat to the environment. The threat can be reduced by upcycling construction and demolition waste (CDW) in the production of foam concrete, which is a special type of concrete used especially for thermal insulation purposes. This study aims to use of CDW as a source of fine aggregate (0–4 mm) in the production of foam concrete mixtures. A series of mixtures with target density values between 500 and 900 kg/m3 were designed with various recycled aggregate and foam contents to investigate the physical, mechanical and thermal properties of the mixtures. Findings of the study reveal that mixtures with an elevated foam content possess a greater number of larger pores, which, as observed through microscopy, form interconnected structures that are porous. On the other hand, adding more fine recycled material (FRM) makes the matrix denser, which reduces the overall porosity and increases the packing density. In contrast to increased content of FRM, correlation coefficient of (−0.77) reveal a more powerful inverse relationship between risen level of foam content (−0.67) and the reduction ratio of fresh-to-dry density and the increase in compressive strength from 7 to 28 days. It is also known that mixes with more foam have better thermal insulation because they trap more air, while mixes with more FRM show an increase in thermal conductivity. The sensitivity analysis showed that changes in thermal conductivity are almost three times as sensitive for FRM content, which means they have a bigger effect than changes in foam content. Employing the Taguchi method, (R_0.714) emerges as the most efficient tested combination indicative of superior overall performance. Notably, the Taguchi method predicts the untested combination (0.100-F/C ratio + 0.714-R/C ratio) as potentially more efficient, suggesting avenues for further exploration and optimization. This study furnishes valuable insights into sustainable construction practices by reutilizing CDW in foam concrete production, thereby contributing to both environmental conservation and enhanced structural outcomes.

Spontaneous self‐assembly of magnetic nanoparticle chains, at the first stage of a gas aggregation source

AbstractThere is an increasing interest in magnetic nanoparticles (MNPs) and self‐assembled MNP chains for applications in biomedicine, catalysis, and other technologically relevant applications. In this work, we report the spontaneous self‐assembly of MNPs at the top surface of the shield of a magnetron sputter head. The resulting nanostructures consisted of clustered nanoscale chains arranged in highly oriented microfibers, with lengths of micrometer order and diameters ranging from 20 to 600 nm. The intense magnetic field gradient around the sputter magnetron's head is the driving force of the self‐assembly process, also trapping species that would otherwise be lost in the carrier gas flow.

Using Color Measurements to Quantify Aggregate and Asphalt Emulsion Compatibility

The compatibility of asphalt emulsion and aggregate plays a significant role in the aggregate retention performance of chip seals. There are several, similar standardized test methods available for assessing the compatibility of emulsion–aggregate blends, including AASHTO T 59, ASTM D244, and North Carolina Department of Transportation (NCDOT) A-24. In all methods, a sample of aggregate and emulsion is mixed and rinsed. Subsequently, the compatibility of the rinsed sample is reported as “good,”“fair,” or “poor” based on visual inspection of asphalt coating the aggregate surface area. These visual inferences are subjective, making them susceptible to potential operator bias. The aim of this study is to develop an objective means to quantify emulsion–aggregate compatibility by using the Asphalt Compatibility Tester to obtain color-based measures in lieu of the visual assessment procedures. Multiple aggregate sources (granite, limestone, and lightweight), emulsion types (CRS-2L, CRS-2, and SS-1h), and sources were evaluated. In total, 25 emulsion–aggregate blends were analyzed. The results were used to establish color index thresholds to capture good- versus fair- or poor-performance emulsions. Additionally, chip seal samples from five construction projects were subjected to the Vialit test to measure aggregate retention performance. The Vialit test results were compared with the compatibility test results as a preliminary evaluation of the color-based criteria proposed here. The results indicated that the NCDOT A-24 procedure coupled with color measurements is effective at capturing the compatibility of emulsion–aggregate blends, providing a potential means to remove the subjectivity of the current visual rating procedures.

A Concentrically Moveable Erosion Zone Magnetron for In Operando Tailoring of Alloy Nanoparticles in a Gas Aggregation Source

AbstractOne particularly interesting approach for the deposition of highly pure nanoparticles (NPs) in a solvent‐ and surfactant‐free process is the gas phase synthesis of nanoparticles using a gas aggregation source (GAS) based on magnetron sputtering. Apart from the possibility of tuning the NP size‐distribution via process parameters, e.g., gas flow, pressure, and aggregation length, multicomponent targets in a GAS enable in operando composition tuning of alloy NPs. However, in the practical application of the GAS, two main challenges have to be addressed: low target utilization and low conversion efficiency. This work describes a magnetron with a concentrically moveable erosion zone (cMEZ magnetron), and showcases its applicability for the deposition of metal (Cu) and metal alloy (CuNi) NPs via GAS. The cMEZ magnetron relies on an in operando reconfigurable outer magnet array, which enables tuning of the position of the erosion zone, impacting target utilization. By weighting the targets and substrates before and after deposition, the conversion efficiency is determined for different operating pressures and magnet configurations. Furthermore, the multicomponent target approach is tested with the cMEZ magnetron, which enabled the in operando composition tuning of the Ni content in CuNi NPs from ≈5 to ≈35 at% only by varying the magnetic field.

An Experimental Study of Concrete Mixed with Coconut Shell as Partial Replacement of Course Aggregate

The high cost of conventional construction materials affects the economy of structure. The possibility of utilizing recycled coconut shell aggregates in concrete as coarse aggregate is examined in the present study. An optimum percentage replacement of coarse aggregate with coconut shell aggregate is determined from the study. Coconut shell is a lightweight material thus producing lightweight concrete. The replacement of coarse aggregate of coconut shell by 10%, 20% and 30%. The Design mix used is M20 grade and testing of specimens are conducted after 7 and 28 days of curing. The flexural and compressive strength of concrete are tests. The main objective is to encourage the use of these waste products as construction materials in low-cost housing Aggregate is a major ingredient for making concrete, occupying almost 70-80% part of concrete. Conventionally crushed rocks are used as coarse aggregate and river sand as fine aggregate. Both are naturally available materials. Due to the speedy growth of construction works, conventional aggregate sources are exhaust very fast leading to a significant increase in the cost of construction. For sustainable development, these materials should be used wisely and alternative materials need to be searched to replace regular aggregate. A large number of studies have been done to search for alternative materials for the production of concrete. At the same time due to fast industrialization, production of waste material is increasing day by day. Its disposal has become a real problem. It can be concluded that the ideal amount of coconut shell replacement for coarse aggregate for M20 Concrete is 10% -20%. Key Words: Concrete Mix, Coconut shell, Low cost housing, Flexural strength, Compressive strength, Design mix, Replacement of Course Aggregate.

Determination of ASR in Concrete Using Characterization Methods

Basaltic rocks are the main source of local crushed rock aggregate for concrete in their region. Basaltic rocks are also potential rocks for alkali–silica reaction (ASR). ASR is a complex mechanism that deteriorates concrete via creating volumetric expansion over time between the reactive silica in the aggregate and the alkali components in Portland cement. However, due to the multi-scale nature of this long-term phenomenon, understanding its mechanism in concrete structures remains difficult to assess. In this study, the morphology and analytical composition of three groups of concrete prepared with basalt aggregate, basalt aggregate with 20% fly ash substitution of cement, and limestone aggregate were analyzed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDX); it was characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and differential thermal analysis (DTA) and compared with the ASR structure. The (Na + K)/Si and Ca/Si ratios in SEM/EDX analysis and the water peaks in FT-IR and TGA analyses will help to determine the footprint of ASR.

AGGREGATE POTENTIAL OF KHAIRABAD LIMESTONE, KALABAGH-MIANWALI, PAKISTAN

Quality of aggregate material reflects the physical, chemical and mineralogical properties of source rock. Limestone is main source of crushed rock aggregate, which is largely used by construction industry. There are few geological formations in Kohat-Potwar province which qualify the specific criteria for utilization as aggregate in building material. Khairabad Limestone exposed in Kalabagh area in Western Salt Range contains colossal quantity of minable aggregates. That’s why, we quantitatively examined this limestone of Paleocene age through several physical, chemical, mineralogical, engineering and mechanical tests to evaluate its aptness as aggregate material. AASHTO, ASTM, BS and NHA designated engineering tests including Los Angles Value (26.59%), Aggregate Impact Value (13.91%), Aggregate Crushing Value (12.84), soundness value (1.84%), coating and stripping of bitumen (96.4%), specific gravity (2.7), water absorption (0.83%), unit weight (1.65 g/cm3), total (elongation + flakiness) index (22.78%), and petrographic analysis (ASR &amp; ACR) revealed that it is highly feasible aggregate resource with suitable properties. Investigated reserve is vast and thick enough to provide aggregate material to nearby local construction as well as national megaprojects. It would be a good contribution to the rising demand of construction materials in the country.

Using tribological approach to assess production temperatures of asphalt binders

In this study, ball on three plates (BOTP) experiment has been used to propose an approach for evaluating the mixing and compaction temperatures of asphalt binder. The results are compared and correlated with equi-viscous- and workability- based methods to arrive at the proposed criterion. A viscosity grade binder, VG30, was modified with varying dosages of Sasobit and Rediset, and the study was executed considering two different types of aggregates (Granite and Dolerite). It was found that warm mix asphalt (WMA) binders can reduce the production temperatures of VG30, irrespective of the test methodology. Equi-viscous method was found to be inappropriate in the quantification of the production temperatures of WMA binders. Workability test results indicated that reduction in mixing and compaction temperatures is a function of the type of warm mix additive, dosages used, and aggregate source. Based on the variability of test parameters in BOTP test, a normal load of “1 N” and a sliding speed of “0.3 m/s” were found to give consistent results of coefficient of friction (CoF). The effect of plate type (Granite, Dolerite, and steel) on the values of CoF was found to be insignificant, and the use of steel plates was recommended. The results of BOTP and workability were in good agreement with each other. Temperature ranges corresponding to the CoF of “0.255–0.282” and “0.317–0.350” are proposed for assessing the mixing and compaction temperatures, respectively.