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Soil stabilization, using a variety of stabilizers, is a common method used by engineers and designers to enhance the properties of soil. The use of nanomaterials for soil stabilization is one of the most active research areas that also encompass a number of disciplines, including civil engineering and construction materials. Soils improved by nanomaterials could provide a novel, smart, and eco- and environment-friendly construction material for sustainability. In this case, carbon nanomaterials (CNMs) have become candidates for numerous applications in civil engineering. The main objective of this paper is to explore improvements in the physical properties of UKM residual soil using small amounts (0.05, 0.075, 0.1, and 0.2%) of nanocarbons, that is, carbon nanotube (multiwall carbon nanotube (MWCNTs)) and carbon nanofibers (CNFs). The parameters investigated in this study include Atterberg’s limits, optimum water content, maximum dry density, specific gravity, pH, and hydraulic conductivity. Nanocarbons increased the pH values from 3.93 to 4.16. Furthermore, the hydraulic conductivity values of the stabilized fine-grained soil samples containing MWCNTs decreased from 2.16E-09 m/s to 9.46E-10 m/s and, in the reinforcement sample by CNFs, the hydraulic conductivity value decreased to 7.44E-10 m/s. Small amount of nanocarbons (MWCNTs and CNFs) decreased the optimum moisture content, increased maximum dry density, reduced the plasticity index, and also had a significant effect on its hydraulic conductivity.

The stabilization and enhancement of the engineering properties of fine and coarse grained soil has heavily relied on reinforcement and admixture materials. This study discusses the effect of the additive of Carbon nanofibers (CNF) on the characteristics of soils in terms of shear strength. The content of CNF was changed within the range of 0.05 to 0.2% by total dry weight of the reinforced samples. In achieving the objective of minimizing the number of experimental runs and thus conserve material, time as well as overall cost, the Box–Behnken approach was chosen as the method for statistical prediction. The scanning electron microscopy (SEM) and Atomic force microscopy (AFM) has been utilized in studying features of CNF in stabilized soil samples and force at the origin of the cohesion (c) of soil. Test results reveal that the increases peak and residual shear strength of the reinforcement soil samples were increased with an increase in the CNF content. The pre-eminence of ionic correlation forces in the cohesion of soil was confirmed by the force (cohesion) measurements by (AFM). The statistical prediction’s relatively high correlation coefficients justified the results.

Mixing of nano-sized powders with soils (macro-sized powders) is a noteworthy issue for geotechnical projects. Thus, this study examined the horizontal ball mill mixing of nano-copper oxide with kaolinite. Ball milling parameters (rotation speed, weight ratio of balls to powder and milling time) of the planetary ball milling were optimized for proper mixing of nano-copper oxide and kaolinite powder. Results showed that increase in mixing time decreased the agglomeration of nano-copper powders and kaolinite and increased the homogeneity of nano-copper powder with kaolinite particles. The quality of mixing was assessed through intensity and scale of segregation using concentration data obtained through energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analyses. It was observed through these two tests that, increase in ball milling time after 6 hours resulted in grain size reduction. Field emission scanning electron microscopy analysis showed that nano-coppers were regularly found on the surface of kaolinite particles after 6 hrs. of horizontal milling at 4:1 ratio of balls to powder mixture. Furthermore, 24 hrs. mixing resulted in grinding of kaolinite particles and hence their size was reduced. Particle size analysis confirmed these results, as the highest size span value of 3.417 was observed after 6 hrs. milling with speed of 200 rpm.

The road distresses have caused too much in maintenance cost. However, better understandings of the behaviours and properties of asphalt, couples with greater development in technology, have allowed paving technologists to examine the benefits of introducing additives and modifiers. As a result, modifiers such as polymers are the most popular modifiers used to improve the performance of asphalt mix. This study was conducted to investigate the use of epoxidized natural rubber (ENR) to be mixed with asphalt mix. Tests were conducted to investigate the performance characteristics of ENR-asphalt mixes, where the mixes were prepared according to the wet process. Mechanical testing on the ENR-asphalt mixes have demonstrated that the asphalt mix permanent deformation performance at high temperature was found to be improved compared to the base mixes. However, the durability studies have indicated that ENR-asphalt mixes are slightly susceptible with the presence of moisture. The durability of the ENR-asphalt mixes were found to be enhanced in term of permanent deformation at high and intermediate temperatures compared to the base asphalt mixes. As conclusion, asphalt pavement performance can be enhanced by using ENR as modifier to face the major road distresses.

This paper presents the improvement of the unconfined compressive strength (UCS) of soil by mixing different percentages of nanolime and 5% lime with soil. The UCS of treated soil increased significantly over curing time with increasing percentage of nanolime. The optimum results were reached at only 0.5% nanolime admixtures which were much higher than 5% lime admixture. This may be due to higher ability of nanolime to flocculate and agglomerate the soil particles compared with the lime. In addition, the lime could fill only the micropores while nanolime could fill the micro- and nanopores as well. The strength gain is inversely proportional to the remolded moisture content and curing period. However, when the content of nanolime used is larger than 0.5%, nanolime particles are not uniformly dispersed. Therefore, a weak area in the form of voids is created, consequently the homogeneous hydrated microstructure cannot be formed, and finally the strength will decrease.

Nanocarbons (NCs) have exceptional mechanical, electrical, and thermal properties as compared to conventional carbon fibers. In previous studies, chemical agent has been used to disperse NCs in the colloid. The main objective of this study is to investigate the dispersion stability of NCs in distilled water and measurement the Zeta Potential value after using ultrasonic dispersion method (physics method). Two types of NCs were used in this study, carbon nanotube (CNT), and Carbon nanofiber (CNF) with different amounts and sonication time of 2 to 12 minutes. The field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) is utilised to inspect the efficiency of the dispersion methodology. The result has shown the significate dispersion of NCs. It was found that the Zeta Potential was 57.5 mV, and 50.9 mV for CNT, and CNF respectively after one month of sonication process. Moreover, the result indicates that the solution is in good stability according to ASTM standard D418-82. Thus, this physical method used in this study can be further considered as a potential method for NCs dispersion when mixed with a different application. Keywords: Nanocarbons, Dispersion, Zeta Potential, Sonication, Nanomaterials

The two types of nano carbons (NCs); carbon nanofibers (CNFs) and carbon nanotubes (CNTs) have been studied in numerous research works, which can extraordinarily enhance the mechanical properties of structural composites (concrete or soil-cement). Their amazing mechanical properties and tremendously high aspect ratios make NCs as the most valuable nanomaterials for nano-reinforcement. Yet, the dispersion of NCs is the major factor that strongly affects the properties of nan composites. A good deal of research has been carried out on chemical methods (chemical agent) to attain homogeneous dispersion of nano carbon in water. While if not precisely done, it can damage or shorten NCs and at the worst can dissolve them. This results in a negative effect on composites. Considering this, NCs can be physically dispersed in water and then mixed with composites. This paper presents a discussion on types of NCs and different dispersion techniques (chemical and physical), and research works in improve of soil properties use NCs.

Dual antiplatelet therapy (DAPT) is commonly used for secondary stroke prevention, but the optimal timing and duration of treatment remain uncertain. This meta-analysis investigated the efficacy and safety of DAPT compared to any single antiplatelet therapy in stroke patients. We examined the effectiveness of DAPT versus monotherapy, stratified by stroke type, timing of intervention onset, and duration of DAPT. We systematically searched electronic databases for randomized controlled trials (RCTs) comparing DAPT with any single antiplatelet therapy in stroke patients. Data from 30 RCTs involving 75,504 patients were pooled using a random-effects model. The key outcomes were recurrent ischemic stroke, major adverse cardiovascular events (MACE), and major bleeding. Additional studied outcomes included hemorrhagic stroke and mortality. Subgroup analysis examined the effectiveness of DAPT versus any single antiplatelet therapy, stratified by stroke type (ischemic stroke, lacunar stroke, and TIA or ischemic stroke), timing of intervention onset (within 12 h, 24 h, 48 h, 72 h, and 7-180 days), duration of DAPT (short-term: up to 30 days; long-term: beyond 30 days) and DAPT regimens (Aspirin and Clopidogrel, Aspirin and Cilostazol, Aspirin and Dipyridamole, and Clopidogrel and Cilostazol, etc.). DAPT significantly reduced recurrent ischemic stroke (RR 0.69, 95% CI 0.60-0.79) and MACE (RR 0.77, 95% CI 0.69-0.87), but did not significantly affect hemorrhagic stroke (RR 1.28, 95% CI 0.80-2.07), major bleeding (RR 1.10, 95% CI 0.91-1.33), or mortality (RR 1.01, 95% CI 0.88-1.15). Subgroup analyses showed that aspirin plus clopidogrel reduced recurrent stroke (RR 0.69, 95% CI 0.59-0.82) and MACE (RR 0.82, 95% CI 0.75-0.91). Early DAPT initiation (within 12-24 h) significantly reduced recurrent ischemic stroke (RR 0.73, 95% CI 0.57-0.92 and RR 0.66, 95% CI 0.52-0.84, respectively) and MACE (RR 0.78, 95% CI 0.62-0.98 and RR 0.81, 95% CI 0.72-0.93, respectively), but increased major bleeding (RR 2.32, 95% CI 1.10-4.86 and RR 1.34, 95% CI 1.20-1.49, respectively). Short-term DAPT (≤30 days) showed a greater reduction in recurrent ischemic events (RR 0.65, 95% CI 0.53-0.79) than long-term DAPT (>30 days; RR 0.72, 95% CI 0.60-0.86). DAPT effectively reduces recurrent ischemic stroke and MACE, especially when initiated within 12-24 h using aspirin plus clopidogrel. Short-term DAPT (≤30 days) may be optimal for recurrent stroke prevention. Clinicians should carefully weigh benefits and risks when personalizing DAPT strategies.

This study aimed to evaluate the effects of carbon nanofibers (CNFs) on the performance of liquid epoxidized natural rubber (LENR)-modified asphalt. The physical, adhesion and rheological properties were determined by several tests such as penetration, elastic recovery, ring and ball softening point, Brookfield rotational viscometer, AFM and dynamic shear rheometer. LENR was used at concentrations of 3, 6, and 9%, while CNFs were used at contents of 0.3, 0.4, and 0.5% by weight of asphalt. Conventional test results showed that the increases in LENR and LENR/CNFs composite contents in binder leads to an increase in the hardness and consistency and a reduction in the temperature susceptibility of base asphalt. Adhesion results revealed that the addition of CNFs significantly increases the adhesion and bonding properties of base and rubberized binders. Rheological properties analysis exhibited that LENR improved the viscoelastic properties and permanent deformation resistance of asphalt at different temperatures and frequencies. On the other hand, it was found that the addition of CNFs significantly improves the stiffness, elasticity, and hardness of LENR-modified binders. The 6% LENR and 0.4% CNFs were found to be the optimum to enhance the physical, adhesion, and rheological properties of asphalt in this study. Thus, it can be stated that the addition of CNFs is promising to improve the performance of rubberized binders for high temperature applications.