Papers by Keyword: Calcium Chloride

Abstract: Hydrogels, a type of polymer, can be synthesized from both natural and synthetic sources, including some biopolymers like alginate and chitosan, making them particularly interesting for biomedical applications. The popularity of hydrogels in the medical field is due to their high-water content, flexibility, and biocompatibility. Hydrogels, which can swell in a hydrated state, are capable of controlling the release of active substances in pharmaceutical and biomedical applications. Alginate and chitosan exhibit polyanionic and polycationic properties when dissolved under appropriate conditions, allowing them to interact with each other. This interaction occurs through the carbonyl groups of alginates and the amino groups of chitosan. Alginate also has the advantages of being non-toxic, biodegradable, biocompatible, and non-allergenic. Therefore, these two materials readily form polyelectrolyte complexes. The use of calcium chloride in producing hydrogels is due to its ability to perform ionic cross-linking on polymers such as alginate. Calcium chloride reacts with the carboxylate groups in alginate, forming stable cross-links between polymer chains. This cross-linking process results in a three-dimensional network that provides structure and stability to the hydrogel. The benefits of adding CaCl₂, in addition to facilitating cross-linking, include increasing the viscosity of the alginate solution, which enhances the formation of the alginate matrix. This study demonstrates that the ratio of chitosan to alginate significantly influences the properties of the resulting hydrogel, impacting its swelling ratio, stability, and ultimately, its potential for biomedical applications. Specifically, the optimal ratio of 5A:1C exhibited superior swelling and gel fraction characteristics, suggesting its potential suitability for controlled drug delivery systems. The successful cross-linking confirmed by FTIR analysis further strengthens the viability of this specific composition for biomedical applications.

Abstract: Abrasives play a crucial role in surface blasting, especially in cold climates, where snow and ice significantly challenge transportation infrastructure and road safety. The main purpose of this research is to address the critical need for effective and sustainable winter maintenance techniques. This study examined the possibilities of Basic Oxygen Furnace Slag (BOFS) as a substitute (an abrasive substance) for conventional aggregates in ice-melting applications. Thus, this research assessed the physical properties of BOFS, such as absorption capacity, tested at -5°C, and aggregate angularity test, and designed for evaluation of the surface texture, friction, and percentage of fractured faces in uncompacted voids (SSD%) of the aggregates. Moreover, the potential use of a blend of BOFS with de-icing salts, specifically sodium chloride (NaCl) and calcium chloride (CaCl₂), was investigated as an effective ice-melting agent. For this purpose, three tests were carried out: the petri dish test according to SHRP H-205.1, the polishing ice melting test using a modified ASTM C 944 (rotational cutter), and the surface temperature measurement test. By assessing the performance of BOFS, our goal was to justify its efficacy, offering a practical alternative for regions experiencing severe winter conditions. Eventually, the findings from this study assert that BOFS can be used for surface blasting, indicating its potential as a substitute for traditional abrasives.

Abstract: Calcium chloride is one of the main de-icing salts for removing snow and ice from roads, infrastructures and service areas. It is well known that reinforced concrete structures, if exposed to calcium chloride, can suffer from severe damages due to both corrosion of steel reinforcement and chemical attack of the cement paste. This paper aims at evaluating the resistance to chemical attack of mortars manufactured with different low-carbon binders (alkali activated slag cements, calcium sulphoaluminate cement-based blends, high volume ultrafine fly ashes cements) in presence of CaCl₂-based de-icing salts in cold weather (temperature about 4°C). Results indicated that alkali activated slag-based mortars are quasi-immune to calcium chloride attack due to their mineralogical composition. On the contrary, calcium sulphoaluminate-based blends show the total loss of binding capacity, especially when calcium sulphoaluminate cement is used with gypsum and Portland cement. Finally, the partial substitution of Portland cement with ultrafine fly ash strongly reduces the mass change and the strength loss of mortars submerged in 30 wt.% CaCl₂ solutions due to the strong reduction of calcium hydroxide responsible for the calcium oxychloride formation in the cement paste.

Abstract: In the present work, the effect of temperature on calcium carbonate precipitation in the biomimetic calcium chloride solution was investigated. A spontaneous calcium carbonate precipitate was formed in the biomimetic calcium chloride solution as a result of the carbon dioxide hydration process. The reaction was conducted at different temperature range vary from 30°C to 100°C. The mass of the calcium carbonate precipitate and the pH solution was measured in the study. The finding indicated that an increment of the temperature has led to the fast pH reduction of the solutions to 7.0. However, the process has retarded the calcium carbonate precipitation process. The optimum temperature for higher calcium carbonate precipitation has occurred at the temperature range of 47.5°C – 65°C which gave the highest calcium carbonate precipitate at 0.121g. The addition of Tris buffer into the calcium chloride solution in this study did not gave an inhibition effect on the calcium carbonate precipitate. Based on the results, an operating condition at 47.5°C – 65°C was recommended to be used in mineral carbonization of CO₂ using the biomimetic calcium chloride solution.

Abstract: The cinnamon essential oil has antibacterial characteristic and sensitive to light and oxygen [1]. Due to its benefits from cinnamaldehyde, this compound has already used for antibacterial agent injected in polymer film [2]. Films are usually made from natural polymers as their main materials such as pectin. This research observed the influence of calcium chloride addition (0; 0.01; 0.02; and 0.03 g/mL solution) in the physical characteristics of pectin based edible films using the immersion method. The results indicated that calcium chloride content did not effect significantly. On the other hand, increasing calcium chloride content increased the water sorption of phosphate buffer saline solution and 0.03 g/mL of calcium chloride offered the lowest water sorption. Addition of cinnamaldehyde affected the surface morphology of the film and gave the crystal structure on the surface.

Abstract: Nearshore’s facilities are often require frequent and regular maintenance dredging in maintaining appropriate water depths and enlarging the access channel and turning basin. A large amount of sediment was spawned from the dredging work. The dredged marine sediments (DMS) are not apt to be used in construction activities because of its poor geophysical properties. The purpose of this research is to study the improvement in moisture content and strength of DMS by using electrokinetic (EK) method. DMS are classified as a high plasticity silt (MH) with 240.74 % of its natural water content. Stainless steel plate was invoked as the electrode, while distilled water (DW), citric acid (CA) and calcium chloride (CaCl₂) were applied as the stabilizing agents. The aforementioned stabilizers are electrically injected into the DMS which causing flow of the solutions through the pores in DMS under 50 V/m of applied direct current (DC). The results of treated DMS are presented in moisture content, undrained shear strength and SEM-EDX analysis. The EK treated DMS shows it increases in strength in the dry zone area after the 14 days treatment. The dry zone area was created near the anode and wet zone was made near the cathode. The application of calcium ions in the treatment had increased the strength and alters the pattern of the soil fabric. Largely, EK has significantly improved the quality of DMS even though the strength increase observed was not homogeneous throughout the specimen.

Abstract: Chemical admixtures are frequently used to regulate the setting and strength development of concrete materials. In this study, tricalcium silicate (C₃S) was used as a model of the cement system, and the influence of calcium chloride, an extremely useful accelerator, on C₃S hydration and the pore structure of hardened C₃S paste were investigated by the combination of the techniques of differential scanning calorimetry (DSC) and the N₂ adsorption (BET). The results indicated that the addition of calcium chloride would significantly shorten the pre-induction and induction periods and enhance the specific surface area and porosity of hardened C₃S paste. However, the presence of CaCl₂ has little effect on the pores, with a width ranging from 2.5 nm to 5 nm. DSC technique has an advantage of measuring continuously the process of C₃S hydration by changes of free water in hydrated C₃S.

Abstract: The authors obtained fine grain concrete based on the mortars of additives-electrolytes undergone mechanic magnetic activation and characterized by improved compression and bending strength and enhanced freeze-thaw resistance. There was investigated the impact of mechanic magnetic activation (MMA) on mixing water when adding calcium chloride and sodium thiosulphate as well as on porosity of cement stone and specific features of phase formation in cement stone. It was stated by the authors that MMA facilitates formation of nucleation centers in activated water in the presence of additives-electrolytes, optimization of porous space as well as crystallization of calcium carbonate in the form of aragonite when lowering the content of Portlandite. The mechanism of joined influence of hydrodynamic and magnetic treatment of mixing water has been determined.

Abstract: In this work, hybrid membranes were obtained with the addition of calcium chloride (CaCl₂). Hybrids were obtained by the melt intercalation method. Membranes were prepared by phase inversion technique. Hybrid and hybrid membranes were characterized by differential scanning calorimetry (DSC). The DSC curve of the polymer and polymer membrane was changed by addition of the clay, increasing the degree of crystallinity. For all membranes, it was observed the existence of two endothermic peaks corresponding to the two crystalline phases of the polymer characteristics, in the range of 220 °C related to the alpha phase and, in the range of 210 °C related the gamma phase. In addition, there was the appearance of an endothermic peak at about 70 °C, related to the temperature of the dry polymer glass transition. The addition of CaCl₂ changed the crystalline behavior of hybrids, becoming less evident the nucleating effect of the clay.

Abstract: A thermodynamic analysis of the reactions of calcium chloride and calcium nitrate with tricalcium aluminate when used as a hardening accelerator for portland cement, as well as decomposition reactions of calcium hydrochloraluminate (CHChA) and calcium hydronitroalyuminate (CHNA) formed during the hardening was performed. The conditions of stable existence of CHChA and CHNA in the cement matrix were established.