Strength Of Aggregates Research Articles

Characterization of Interface Transition Zone in Asphalt Mixture Using Mechanical and Microscopic Methods.

An enormous surge in the pavement sector requires the evaluation of interface bonding in asphalt composite, since the assessment of bonding brings considerable cost savings. Microscopic and mechanical analyses were performed to study the status of the interface transition zone of four groups of asphalt mixtures, using thin-slice preparation to obtain asphalt mixture slices with a flat surface for microscopic analysis. The interface transition zones were characterized using good knowledge of blending or diffusion phenomena by conducting tests both at the micro and macro levels to determine mixture quality. Asphalt mixture components were observed using fluorescence microscopy imaging and evaluated by the gray value change law. Asphalt mixture groups, (virgin, recycled of 30% aged and 70% unaged, 6%, and 4% rejuvenator dosage mixtures) under the same process parameters, which are a mixing time of 270 s and a mixing temperature of 150 °C, been considered optimum for component fusion in a hot asphalt mixture were used. This study relied on the influence of morphology law, assessed through rutting tests for high temperature performance, semi-circular bending tests for low temperature performance, and pull-off tests for interface bonding strength. The relationship between interface transition zones and macro performance was studied. The self-developed pull-off method was a research innovation which can be used as an alternative to study interface transition zones in asphalt mixtures, and provides the necessary data needed with 3D surface failure mode calculations. The device measured the bonding strength of a single aggregate in distinct positions using the bitumen penetration test method. The main goals were to determine a correction factor, identify the appropriate alteration, and compute the actual fracture surface area. Using scanning electron microscopy for interface characterization and micro-morphologies of mortar transition zone, our analysis provides adequate knowledge about interface position and the components present. The applied approaches to characterize asphalt mixture interfaces proved workable and reliable, as all methods have similar trends with useful information to determine asphalt pavement quality.

Size distribution of aggregates across different aquatic systems around Japan shows that stronger aggregates are formed under turbulence

AbstractMarine aggregates, composed of various particles, play a crucial role in ocean carbon storage. The overall size distribution of the aggregates (number size spectra) is controlled by the balance between aggregation and disaggregation processes. Turbulence has been proposed to facilitate both aggregation and disaggregation by increasing the collision rate of aggregates or sometimes directly tearing them apart. Predominant processes driven by turbulence typically depend on the level of turbulence—relatively weak turbulence is associated with aggregation while stronger turbulence promotes disaggregation. Aggregate strength also plays a key role, as strongly bonded aggregates can withstand turbulence better, leading to lower disaggregation rates. While the relationship between turbulence and aggregate strength has been studied numerically and experimentally, field measurements remain limited. Here, we compare our number size spectra to turbulence intensity from the field measurements across different environmental settings around Japan to determine the effect of turbulence on aggregate strength. We combined measurements from 10 sites with different environmental settings and observed the flatter slopes (higher net aggregation rate) and shifts in the intersection lengths with an increase of turbulence, while strong turbulence is typically linked with disaggregation. Our findings suggested that stronger aggregates are formed under stronger turbulence and the overall population of strong aggregates also increases with an increase of turbulence intensity. We also compared our number size spectra with three other confounding factors (fluorescence, salinity, and aggregate compositions) to confirm the effects of turbulence are dominant in our aggregate dynamics.

Comparison of Curing Conditions on Physical Properties, Mechanical Strength Development, and Pore Structures of Phosphogypsum-Based Cold-Bonded Aggregates.

This study compared the physical properties and mechanical strength development of PCBAs with water, sealed, standard, and open ambient air curing over 28 days to find a suitable curing method for the production of phosphogypsum-based cold-bonded aggregates. The types and relative amounts of hydration products, microstructural morphology and pore structure parameters were characterized utilizing XRD, TGA, FTIR, SEM and nitrogen adsorption methods. According to the results, water curing leads to rapid increases in single aggregate strength, reaching 5.26 MPa at 7 d. The standard curing condition improved the 28 d mechanical strength of the aggregates by 19.3% over others by promoting the generation of hydration products and the transformation of the C-S-H gel to a higher degree of polymerization and by optimizing the pore structure. Further, PCBAs achieved an excellent solidification of phosphorus impurities under all four curing conditions. This work provides significant guidance for selecting an optimized PCBA curing method for industrial production.

Experimental and 3D mesoscopic numerical simulation study of kinetic projectile penetrating into concrete

Concrete is a multiphase composite material composed of mortar, aggregate, and interface transition zone (ITZ). The mesoscopic components of concrete have an important influence on its anti-penetration performance. In this study, a series of penetration experiments with large-caliber ogive-nosed projectiles penetrating concrete targets are carried out. The test results show that the damage to the concrete target consists of crater and tunnel zones and increases with increasing impact velocity. Then, a local background grid method is proposed to establish a 3D mesoscopic model of concrete, based on the arrangement characteristics of the sequence number of the finite elements. Compared with the traditional 3D mesoscopic concrete modeling method, the proposed method can effectively improve the modeling efficiency. Subsequently, numerical simulations are performed based on the 3D mesoscopic model, with the simulation and experimental results in good agreement, verifying the effectiveness of the model. Finally, the verified 3D mesoscopic model is employed to investigate the effects of shape, volume fraction, size interval, and strength of the concrete aggregates on the depth of penetration (DOP) and deflection of the projectile. The simulation results indicate that the shape of the aggregate has a negligible effect on both uniaxial compressive strength and DOP. Therefore, spherical aggregates are used to improve modeling efficiency. Increasing the volume fraction and strength of the aggregates can significantly enhance the anti-penetration performance of concrete. The influence of aggregate size interval on DOP is slight, but it has a significant impact on projectile and trajectory deflection at the same aggregate volume fraction. The uneven lateral resistance on both sides of the projectile, caused by the random distribution of aggregates, is a major factor in deflection.

Turning waste concrete powder into high calcium alkali-activated cementitious materials and artificial aggregates

In order to handle the environmental pollution caused by waste concrete powder, recycled concrete powder (RCP) is utilized to prepare high calcium alkali-activated cementitious materials and artificial aggregates. This study first investigates the high calcium alkali-activated cementitious materials, exploring the effects of different mineral admixtures, liquid-to-solid ratios (L/S), RCP/slag, Na2SiO3 modulus, and Na2O content. The results illustrate that slag powder is the best mineral admixture and the most critical factor affecting cementitious materials. Increasing the slag dosage enhances the generation of C-(A)-S-H, improves the microstructure, and increases compressive strength, with a maximum compressive strength reaching 68.42 MPa. According to these test results, the impact of various factors on RCP aggregates is further explored. The results illustrate that the L/S and slag content are primary factors influencing particle size distribution and strength. Increasing these factors leads to larger aggregate particle sizes and higher strength. The compressive strength of the aggregates at 7d reaches 93.24–-99.5 % of that at 28d, with a maximum strength of 8.2 MPa. Additionally, slag content (10–30 %) and Na2O content significantly impact the physical properties of aggregates, improving apparent density and bulk density while reducing water absorption. To verify the applicability of RCP aggregates, they were used in concrete, and the effects of aggregate strength and replacement rate on concrete performance were explored. The results display that as aggregate strength rises, the mechanical properties of the concrete improve. When RCP aggregates are incorporated, the mechanical properties of the natural concrete decline only slightly (<16.70 %). The probability of aggregate damage increases with decreased RCP aggregate strength or increased RCP aggregate content under pressure. RCP aggregate concrete exhibits better shrinkage resistance compared to natural concrete. The process of utilizing RCP is low-energy, non-polluting, and results in high-performance products, making the large-scale effective utilization of RCP feasible.

The Bulk Densities of Small Solar System Bodies as a Probe of Planetesimal Formation

Constraining the formation processes of small solar system bodies is crucial for gaining insights into planetesimal formation. Their bulk densities, determined by their compressive strengths, offer valuable information about their formation history. In this paper, we utilize a formulation of the compressive strength of dust aggregates obtained from dust N-body simulations to establish the relation between the bulk density and diameter. We find that this relation can be effectively approximated by a polytrope with an index of 0.5, coupled with a formulation of the compressive strength of dust aggregates. The lowest-density trans-Neptunian objects (TNOs) and main-belt asteroids (MBAs) are well reproduced by dust aggregates composed of 0.1 μm sized grains. However, most TNOs, MBAs, comets, and near-Earth asteroids (NEAs) exhibit higher densities, suggesting the influence of compaction mechanisms such as collision, dust grain disruption, sintering, or melting, leading to further growth. We speculate that there are two potential formation paths for small solar system bodies. One involves the direct coagulation of primordial dust grains, resulting in the formation of first-generation planetesimals, including the lowest-density TNOs, MBAs, and the parent bodies of comets and NEAs. In this case, comets and NEAs are fragments or rubble piles of first-generation planetesimals, and the objects themselves or the rubble are composed of 0.1 μm sized grains. The other path involves the further potential fragmentation of first-generation planetesimals into the compact dust aggregates observed in protoplanetary disks, resulting in the formation of second-generation planetesimals composed of compact dust aggregates, which may contribute to explaining another formation process of comets and NEAs.

A novel use of incineration bottom ash for H2 aeration in the production of artificial lightweight aggregates

Cold bonding is an energy-efficient method for producing artificial aggregate (AA). However, the relatively high density of AA restricts its use in lightweight concrete products. This study aims to fully upcycle aluminum (Al) content in municipal solid waste incineration bottom ash (IBA) for H2 aeration in the production of lightweight artificial aggregate through alkali activation. To achieve this, the glass particles (GP) in IBA were ground into powder and used as the precursor for NaOH, while the remaining IBA (RIBA), rich in Al, served as the foaming agent. The results showed that RIBA particles (<300 μm) can be used to produce lightweight AA with a loose bulk density ranging from 780 to 840 kg/m3, comparable to sintered fly ash aggregates, and a wide pore size distribution ranging from 0.02 mm to over 1 mm. The inclusion of finer RIBA particles (<75 μm) enhanced the homogeneity of the pore structure, resulting in aggregate strengths of 0.4–0.6 MPa. Moreover, increasing the GP content in IBA up to 40% further boosted the aggregate strength to 1.1 MPa by refining the pore structure and promoting more (C)-N-A-S-H gels with Q4 structures. To ensure sufficient geopolymerization reactions and achieve high strength in the AAs, the alkali concentration should be kept above 3 mol/L. The proposed strategy for lightweight AA production reduced the global warming potential by about 20% compared to the conventional sintered method, offering a more environmentally friendly approach.

Aggregate structure of agro-gray soils of Vladimir Opolye: composition and strength of aggregates

A complex of soils characteristic of the Vladimir Opole region was studied: agro-gray typical deep-arable soil, tongue-shaped agrozem and agro-gray gleyic soil. The high contrast of soil properties, which is due to the genesis of field landscapes, can be traced in the differences in the arable and subarable horizons of agro-gray soils at the aggregate and microaggregate levels. The soils have an excellent structural condition, high water resistance and mechanical strength of aggregates. In the aggregate structure of arable horizons, dependences on the position in the relief were found: down the slope the content of agronomically valuable aggregates decreases, the weighted average diameter of aggregates increases, the water resistance of aggregates and the mechanical strength of aggregates at capillary saturation decreases. However, the distribution and size of microaggregates, as well as the strength of aggregates in an air-dry state, reflects the complex genesis of the landscape and retains the influence of paleorelief with depressions and elevations. The weighted average diameter of microaggregates of arable horizons of the soils of the Vladimir Opole region is close to the chernozems of the Kursk region. The granulometric composition of the studied soils is typical of Vladimir Opolye soils and close to each other. In accordance with the classification of N.A. Kachinsky arable horizons are medium loamy, coarse silt, BT horizons are heavy loamy, coarse silt. The most structural is the arable horizon of agro-gray typical deep-arable soil, it has large microaggregates, it also has high water resistance and the highest content of agronomically valuable aggregates. The most homogeneous in terms of aggregate composition is tongue-shaped agrozem; the average diameter of aggregates and microaggregates in the arable and subarable horizons are equal and similar in the content of microaggregates and agronomically valuable aggregates. This soil is also highly water resistant. Agro-gray gleyic soil contains fewer agronomically valuable aggregates and its water stability is unsatisfactory.

Comparative evaluation of blood contamination on the push-out bond strength of mineral trioxide aggregate, Biodentine, and bone cement in furcation perforation repair: An in vitro study

ABSTRACT Aim: This in vitro study was designed to compare the effect of blood contamination on the push-out bond strength of mineral trioxide aggregate (MTA), Biodentine, and bone cement. Materials and Methods: Seventy-eight human mandibular molars with furcation were selected and decoronated at the cementoenamel junction. The samples were mounted 3 mm below the furcation area into the acrylic resin. A perforation in the center of the furcation was made using a round carbide bur size 3 with a diameter of 1.2 mm. Then, the perforation was enlarged up to a standardized diameter of 1.3 mm using a size 5 Gates-Glidden drill. The samples were randomly divided into three groups. Based on blood contamination status, each group (n = 26) was further subdivided into two subgroups (n = 13). Whole fresh human blood was obtained from the principal investigator of the research group. A 27-gauge syringe was used to inject blood into the perforated furcal area. A piece of gelatin was packed under the furcal area using a condenser. MTA, Biodentine, and bone cement were mixed according to the manufacturer’s recommendations and compacted into the perforation. A universal testing machine was used to evaluate the push-out bond strength. Statistical Analysis: The results were analyzed using one-way analysis of variance followed by Tukey’s post hoc test (P &lt; 0.05). Results: In the experimental groups with blood contamination, Group 2A exhibited statistically significant push-out bond strength values compared with Group 1A and Group 3A. In the groups without blood contamination, Group 2B showed statistically significant push-out bond strength values compared with Group 1B and Group 3B. Irrespective of the blood contamination status, Group 3 exhibited higher push-out bond strength values than Group 1, with no statistically significant difference between the groups. No significant difference was observed within the groups. Conclusion: Biodentine showed promising results as a better perforation repair material irrespective of the status of blood contamination. Bone cement can be a viable alternative material for furcation perforation repair compared with MTA.

A comparative assessment of uncrushed-river concrete mix of Hari-River, and Kamar-Kalaq: the two widely used concrete mix in Herat, Afghanistan

Concrete, as a cornerstone of modern construction, heavily relies on the quality of its constituent materials, particularly aggregates. Among the critical factors contributing to high-quality concrete are proper gradation, absence of clay particles, and angular shape of aggregates. Adhering to these standards typically results in concrete with superior strength. However, aggregates sourced from riverbeds often possess a natural gradation, contain clay particles, and have rounded shapes. This study delves into a comparative analysis of aggregates sourced from two widely utilized riverbed regions, namely Hari-River and Kamar-Kalaq, situated within Herat province, Afghanistan. Given that over 90% of concrete in Herat province is sourced from these two riverbeds, the findings of this study carry immense significance. The research meticulously examines key parameters, including clay content, gradation, aggregate shape, and compressive strength, to determine the optimal choice for concrete production. Methodologically, samples were acquired following ASTM standards, and rigorous testing procedures were conducted, encompassing clay particle analysis, sieve analysis, and strength testing. The results reveal significant disparities between the two regions, with Hari-River demonstrating superior characteristics across various metrics. Particularly noteworthy is Hari-River’s lower clay content of 2.7% compared to Kamar-Kalaq’s 3.7%. The gradation of Hari-River for both coarse and fine aggregates is superior to that of Kamar-Kalaq when compared to size 67 aggregate range. Additionally, the average 28 days concrete compressive strength of Hari-River aggregates is 27.8 MPa, while that of Kamar-Kalaq is 23.4 MPa.

SiO2 aerogel modified aggregates: Preparation, heat resistance and improvement mechanism

Modification of natural aggregates using SiO2 aerogel solution can not only radically reduce the rutting disease of asphalt pavement, but also avoid the problems of poor heat-resistant performance, mechanical strength and durability of ordinary heat-resistant aggregates. The effects of SiO2 aerogel solution type, modification method and SiO2 aerogel solution dosage on the thermal resistance and adhesion properties of SiO2 aerogel-modified aggregates (SM-Agg) were explored by orthogonal tests. Based on scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and infrared thermography, the surface micromorphology, elemental composition and dynamic thermal resistance properties of natural aggregate and SM-Agg were analyzed, respectively. The results showed that Both SiO2 aerogel solution type and dosage significantly affect the evaluation indexes and the modification of natural aggregates by soaking method using ZN-S type SiO2 aerogel solution with 15 % of the aggregate mass could obtain SM-Agg with good heat resistance and adhesion properties. The surface of SM-Agg was covered with a “gel layer” containing uniform and densely distributed SiO2 aerogel particles. The temperature of the top surface of the 18.3-mm-thick SM-Agg specimen gradually changed from 2.2°C higher than that of the natural aggregate to about 1.8°C lower than that of the natural aggregate within 60 min of heating at 55°C. The “gel layer” containing SiO2 aerogel particles forms one or more layers of three-dimensional heat-blocking mesh on the aggregate surface, which dramatically reduces the heat transfer area, prolongs the heat transfer path within the specimen, and increases the heat-reflecting capacity of the aggregate surface.

Comparative Evaluation of the Effect of Various Irrigating Solutions on the Push-Out Bond Strength of Biodentine and Mineral Trioxide Aggregate: An In Vitro Study

Introduction: A successful endodontic treatment is ba¬sed on combination of adequate instrumentation, irrigation and obturation of canal system. The objectives of endodontic irrigants are lubrication of root canal, removal of microorganisms, pulp, dentinal remnants and dissolution of tissues. The objective of root-end filling is establishment of proper apical hermetic seal. Aim: To evaluate and compare the effect of various irrigating solutions on push-out bond strength of Biodentine and Mineral trioxide aggregate (MTA). Materials and Method: Sixty-four extracted human single rooted teeth were decoronated 1.5-2 mm coronal to cemento-enamel junction. The root canals were prepared and divided into four groups (n=16): Group I- Normal Saline (Control group), Group II- Triple antibiotic solution, Group III- 2% Chlorhexidine, Group IV- Morinda citrifolia solution. Mid root dentin was sectioned horizontally and irrigated further with respective irrigating solutions for 5 minutes and divided into 2 subgroups: Subgroup A- Biodentine and Subgroup B- MTA. The root-end filling material was incrementally placed and embedded in acrylic blocks. Samples were tested for push-out bond strength using universal testing machine. Results: The highest push-out bond strength was shown by 2% Chlorhexidine group when used with Biodentine and lowest when normal saline was used with Biodentine. Conclusion: All experimental irrigating solutions increased the push-out bond strength of MTA and Biodentine.

Effect of calcium hydroxide and calcium hydroxide nanoparticles used as intracanal drugs after manual and ultrasonic removal on the bond strength of a new sealer with a pozzolan base (Endoseal mineral trioxide aggregate)

ABSTRACT Aim: The adhesion ability of filling materials to the root canal wall can be affected by the intracanal medicaments. The present study investigated the effect of pretreatment with nano-calcium hydroxide and calcium hydroxide on the bond strength of Endoseal mineral trioxide aggregate (MTA) to root canal dentin. Materials and Methods: Fifty maxillary incisor teeth were randomly divided into two experimental groups (n = 20) and a control group (n = 10) after decoronation near the cementoenamel junction and root canal instrumentation according to the type of intracanal medicament (calcium hydroxide and nano-calcium hydroxide). Each experimental group was divided into two subgroups based on manual and ultrasonic drug removal methods. After removing intracanal medicaments and irrigating them, all the groups were obturated with gutta-percha and Endoseal MTA sealer. Then, the samples were sectioned into cross-sections with a thickness of 2 mm using a diamond disc, and the push-out bond strength test was performed on them. Results: The results showed no significant difference in the mean Endoseal MTA bond strength in terms of the type of intracanal medicament and the method used to remove it from the canal (P &gt; 0.05). Conclusion: Using the ultrasonic method compared to the manual method in removing intracanal medicament resulted in no significant difference in the strength of the Endoseal MTA bond. Furthermore, the effect of nanoparticle calcium hydroxide on Endoseal MTA bond strength was not different compared to the conventional type of this medication.

Deposition morphology and mechanical properties of lean cemented gangue backfill material: Laboratory test and field application

Backfilling mining technology provides an efficient and environmentally-friendly solution for treating additional products (such as tailings, coal gangue and other solid waste) in coal mining process, which are filled into the underground goaf area, thus reducing surface subsidence, roof strata damage, and associated geological disasters. In this study, a novel backfill material called lean cemented gangue backfill material (LCGBM) is introduced, and various experiments, including uniaxial compression tests, creep tests, CT-SEM scanning and reconstruction are carried out to evaluate its mechanical properties and engineering practicability. The test results indicate that the strength and volume fraction of self-compacting cement (SCC) slurry and solid waste aggregate jointly control the uniaxial compressive strength and failure mode of LCGBM, reflecting the bucket effect under the influence of two components. Although the volume fraction of aggregate and SCC slurry is intentionally reduced to control the cost, this cemented granular material shows excellent compressive strength, overall stiffness and long-term bearing capacity in laboratory and field tests. In the process of engineering application, the uniaxial compressive strength of the LCGBM reaches 14 MPa, and the initial setting time is 120 s, which reduces the consumption of gangue aggregate by 35 % and greatly reduces the construction time. In addition, a calculation method of the optimal mixing ratio of raw materials is proposed, which can adjust the strength and volume fraction of SCC slurry according to the optimal mixing range, so as to maximize the utilization of the strength of LCGBM, and reduce the construction time and aggregate of backfilling. The research findings emphasize the potential of the LCGBM in promoting clean and sustainable coal mining practice.

Comparative analysis of shear bond strength of MTA and Theracal PT with different restorative materials

BackgroundThis study aimed to compare the in vitro shear bond strength (SBS) of mineral trioxide aggregate (MTA) and dual-cured, resin-modified calcium silicate material (Theracal PT) to composite resin, compomer, and bulk-fill composite, and to evaluate the bond failure mode under a stereomicroscope.MethodsNinety acrylic specimens, each with a 4 mm diameter and 2 mm height central hole, were prepared. These specimens were randomly divided into two groups based on the capping materials: MTA and Theracal PT. Each group was further subdivided into three subgroups (n = 15) according to the restorative materials: composite resin, compomer, and bulk-fill composite. The specimens were then subjected to shear testing using a universal testing machine at a crosshead speed of 1 mm/min. Post-test, the fracture locations were examined using a stereomicroscope. Data were analyzed using a two-way analysis of variance (ANOVA) and the Tukey test.ResultsThe SBS values for the Theracal PT group were significantly higher than those for the MTA group (p < 0.001). Within the MTA groups, no significant differences were observed in SBS values across the different restorative materials. However, a significant difference was found between the mean SBS values of the Theracal PT + composite resin group and the Theracal PT + compomer group (p < 0.001).ConclusionsTheracal PT shows promise in dentistry due to its superior bond strength. Given its bond values, Theracal PT appears capable of forming durable and long-lasting restorations by establishing reliable bonds with various restorative materials commonly used in dentistry.

Investigation of Strength Concrete Materials Using Pozzolanic Additives

In the study, pozzolanic materials serve as replacements for additives, namely Palm Shell Ash (PSA), Coal Fly Ash (CFA), and Rice Husk Ash (RHA). The purpose of the study is to determine the optimum proportion of additives used in high-performance concrete. The addition of 15% PSA resulted in a strength of 69.227 MPa over a test period of 56 days, while the addition of 15% CFA yielded a strength of 69.369 MPa, and the addition of 5% RHA resulted in a strength of 59.984 MPa. The maximum concrete strength is achieved by adding 15% PSA. Correlation analysis between stress-strain indicates that aggregates exhibit higher strength compared to cement paste, mortar, and concrete, highlighting the relationship between the aggregate, cement paste, mortar components, and concrete as a composite material. Aggregate strength values found to be the highest among concrete, cement paste, and mortar, indicating that cement paste contributes the least to the strength of concrete, followed by mortar as concrete reinforcement. The results suggest that aggregates remain the primary strength component supporting concrete. The finding indicates that the relationship between the basic substances in this study aligns closely with existing theory. Moreover, it suggests that all concrete materials with pozzolan variants can classified as high-quality concrete. The optimum percentage is obtained by adding 15% palm shell ash, resulting in the highest compressive strength compared to counterparts and test objects with other types of pozzolan additions. The relationships between the constituents of concrete demonstrate that aggregates continue to be important contributors to concrete strength, with the cement paste contributing the least. Concrete strength values fall between those of aggregates and those of cement and mortar pastes.

Preparation and Properties of Lightweight Aggregates from Discarded Al2O3-ZrO2-C Refractories.

Refractory materials are an important pillar for the stable development of the high-temperature industry. A large amount of waste refractories needs to be further disposed of every year, so it is of great significance to carry out research on the recycling of used refractories. In this work, lightweight composite aggregate was prepared by using discarded Al2O3-ZrO2-C refractories as the main raw material, and the performance of the prepared lightweight aggregate was improved by adjusting the calcination temperature and introducing light calcined magnesia additives. The results showed that the cold compressive strength and thermal shock resistance of the lightweight aggregates were significantly improved with increasing calcination temperature. Moreover, the introduction of light calcined magnesia can effectively improve the apparent porosity, cold compressive strength, and thermal shock resistance of the prepared lightweight aggregates at the calcination temperature of 1400 °C. Consequently, this work provides a useful reference for the resource utilization of used refractories, while the prepared lightweight aggregates are expected to be applied in the field of high-temperature insulation.

Assessment of Fractal Synchronization during an Epileptic Seizure.

In this paper, we define fractal synchronization (FS) based on the idea of stochastic synchronization and propose a mathematical apparatus for estimating FS. One major advantage of our proposed approach is that fractal synchronization makes it possible to estimate the aggregate strength of the connection on multiple time scales between two projections of the attractor, which are time series with a fractal structure. We believe that one of the promising uses of FS is the assessment of the interdependence of encephalograms. To demonstrate this approach in evaluating the cross-dependence between channels in a network of electroencephalograms, we evaluated the FS of encephalograms during an epileptic seizure. Fractal synchronization demonstrates the presence of desynchronization during an epileptic seizure.

Unlocking the Secrets of Residential Construction: Investigating Aggregate Properties for Optimal Building Performance

The objective of this study was to find the strength of aggregates from selected three rivers and suggest to use aggregates for construction from the rivers, where better quality and strong aggregates exists. Aggregates from three selected rivers were tested for, size distribution, aggregate impact value (AIV), Los Angeles abrasion test (LAA). Natural and crushed aggregates were collected and tested for preparing the M20 grade concrete. The mean compressive strength of the concrete made from natural aggregates at 7 and 28 days was fond as 16.72 N/mm2, 16.5N/mm2 and 14.11N/mm2 and 26.22 N/mm2 , 24.29 N/ mm2 and 23.69 N/mm2 for Danda, Jharahi and Boulaha rivers respectively. Similarly, mean compressive strength of concrete made from crushed aggregates at 7 and 28 day was found to be 16.06 N/mm2 , 16.43N/mm2 and 15.16N/mm2 and 26.29 N/mm2, 24.95 N/mm2 and 24.36 N/mm2 for Danda Jharahi and Boulaha rivers, respectively. The null hypothesis (H0) was rejected and alternative hypothesis (H1) was accepted that there exist significant difference in mean value of compressive strength among the river aggregates from selected rivers. However no interaction among the river aggregates was found as Fcalc&lt;Fcrit and Value was found &gt; 0.05 hence null hypothesis was accepted. The higher strength aggregates were found in Danda river whereas lower strength aggregates were found in Boulaha river

Amended soils with weathered coal exhibited greater resistance to aggregate breakdown than those with biochar: From the viewpoint of soil internal forces

Soil erosion is the first threat to soil functions. Reducing the soil aggregate breakdown strength is a key step to improve the soil’s ability to resist rainfall splash erosion. Soil internal forces have been found to be the initial and important forces driving aggregate turnover. The application of exogenous organic materials can effectively improve soil aggregate stability and the resistance to rainfall erosion of agricultural soils. However, from the perspective of soil internal forces, information about the reduction effects of the exogenous organic materials application on soil aggregate breakdown is scarce, especially in comparing the effects of different materials. In this study, weathered coal and biochar were individually applied to loamy clay soil at rates of 0 %, 1 %, 2 %, and 3 % (w/w). Soil internal forces, aggregate breakdown strength, and splash erosion rate of different amended soils were then examined after four years. The results showed that compared with unamended soils (0 %), both weathered coal and biochar applications clearly increased the van der Waals attractive pressure and thus decreased the positive net pressure between soil particles. Additionally, these materials reduced soil aggregate breakdown strength and splash erosion rate. The application effects of the two materials were increased with their application rates. Under a lower electrolyte concentration in soil solution (0.0001 mol L−1), the aggregate breakdown strength in the soils amended with weathered coal was lower than that with biochar by 9.6 %, 23.2 %, and 17.7 % (when the diameter of broken aggregate was < 10 μm) and by 10.3 %, 20.8 %, and 17.5 % (when the diameter of broken aggregate was < 20 μm) at the 1 %, 2 %, and 3 % application rates, respectively (P < 0.05). Additionally, soils amended with weathered coal exhibited lower splash erosion rates compared to those amended with biochar, particularly at the higher application rate of 3 %. From the viewpoint of soil internal forces, weathered coal appears to be a suitable exogenous organic material for improving soil aggregate stability and anti-erosion ability during rainfall events. Our findings provide valuable insights into utilizing exogenous materials to improve soil resistance to rainfall splash erosion, assisting agricultural soil management in areas frequently affected by rainfall erosion.