Explore the vast range of titles available.

Chloride-based deicing salt solutions can react with the calcium hydroxide in the cementitious matrix, leading to the formation of calcium oxychloride. Calcium oxychloride formation has been implicated in the premature deterioration of pavement joints and concrete flatwork across cold regions in North America. This study examines the formation of calcium oxychloride in the presence of blends of different chloride-based deicing salts (sodium and calcium chloride). This evaluation was performed using several plain cementitious pastes and pastes with fly ash, slag, and silica fume used as supplementary cementitious materials. Fly ash and slag were used at 20% replacement levels and the silica fume was used at 3 and 6% replacement levels. Thermogravimetric analysis was used to quantify the amount of calcium hydroxide, and low-temperature differential scanning calorimetry was used to quantify the amount of calcium oxychloride formed. When the salt blends consist of less than 20% of calcium chloride by mass, the amount of calcium oxychloride that forms is low and does not depend on the calcium hydroxide content in the pastes. When the salt blends consist of more than 20% of calcium chloride by mass, the amount of calcium oxychloride that forms depends on the calcium hydroxide content in the paste and increases with calcium hydroxide content. This suggests two strategies to mitigate the amount of calcium oxychloride that is formed: reduction in the amount of calcium hydroxide in the pastes through use of supplementary cementitious materials, and the use of deicing salt blends that include lower amounts of calcium chloride. A model is developed to estimate the amount of calcium oxychloride formed in mixtures, given the calcium hydroxide and calcium chloride contents. Keywords: calcium oxychloride; deicing salts; differential scanning calorimetry; durability; pavements; thermogravimetric analysis.

Deicing agents, primarily road salt, are applied to roads in 26 states in the United States and in a number of European countries, yet the scale of impacts of road salt on aquatic organisms remains largely under-studied. The issue is germane to amphibian conservation because both adult and larval amphibians are known to be particularly sensitive to changes in their osmolar environments. In this study, we combined survey, experimental, and demographic modeling approaches to evaluate the possible effects of road salt on two common vernal-pond-breeding amphibian species, the spotted salamander (Ambystoma maculatum) and the wood frog (Rana sylvatica). We found that in the Adirondack Mountain Region of New York (USA), road salt traveled up to 172 m from the highway into wetlands. Surveys showed that egg mass densities of spotted salamanders (A. maculatum) and wood frogs (R. sylvatica) were two times higher in forest pools than roadside pools, but this pattern was better explained by road proximity than by increased salinity. Experiments demonstrated that embryonic and larval survival were reduced at moderate (500 µS) and high conductivities (3000 µS) in A. maculatum and at high conductivities in R. sylvatica. Demographic models suggest that such egg and larval stage effects of salt may have important impacts on populations near roads, particularly in the case of A. maculatum, for which salt exposure may lead to local extinction. For both species, the effect of road salt was dependent upon the strength of larval density dependence and declined rapidly with distance from the roadside, with the greatest negative effects being limited to within 50 m. Based on this evidence, we argue that efforts to protect local populations of A. maculatum and R. sylvatica in roadside wetlands should, in part, be aimed at reducing application of road salt near wetlands with high conductivity levels.

Ice accretion has adverse effects on a range of commercial and residential activities. The force required to remove ice from a surface is typically considered to scale with the iced area. This imparts a scalability limit to the use of icephobic coatings for structures with large surface areas, such as power lines or ship hulls. We describe a class of materials that exhibit a low interfacial toughness with ice, resulting in systems for which the forces required to remove large areas of ice (a few square centimeters or greater) are both low and independent of the iced area. We further demonstrate that coatings made of such materials allow ice to be shed readily from large areas (~1 square meter) merely by self-weight.

Freeze–thaw damage is one of the most severe threats to the long-term performance of concrete pavement in cold regions. Currently, the freeze–thaw deterioration mechanism of concrete pavement has not been fully understood. This study summarizes the significant findings of concrete pavement freeze–thaw durability performance, identifies existing knowledge gaps, and proposes future research needs. The concrete material deterioration mechanism under freeze–thaw cycles is first critically reviewed. Current deterioration theories mainly include the hydrostatic pressure hypothesis, osmolarity, and salt crystallization pressure hypothesis. The critical saturation degree has been proposed to depict the influence of internal saturation on freeze–thaw damage development. Meanwhile, the influence of pore solution salinity on freeze–thaw damage level has not been widely investigated. Additionally, the deterioration mechanism of the typical D-cracking that occurs in concrete pavement has not been fully understood. Following this, we investigate the coupling effect between freeze–thaw and other loading or environmental factors. It is found that external loading can accelerate the development of freeze–thaw damage, and the acceleration becomes more evident under higher stress levels. Further, deicing salts can interact with concrete during freeze–thaw cycles, generating internal pores or leading to crystalline expansion pressure. Specifically, freeze–thaw development can be mitigated under relatively low ion concentration due to increased frozen points. The interactive mechanism between external loading, environmental ions, and freeze–thaw cycles has not been fully understood. Finally, the mitigation protocols to enhance frost resistance of concrete pavement are reviewed. Besides the widely used air-entraining process, the freeze–thaw durability of concrete can also be enhanced by using fiber reinforcement, pozzolanic materials, surface strengthening, Super Absorbent Polymers (SAPs), and Phase Change Materials. This study serves as a solid base of information to understand how to enhance the freeze–thaw durability of concrete pavement.

Wind turbines operating in cold regions are more likely to sustain extreme icing, causing the degradation of aerodynamic performance and the loss of wind energy output. This paper proposed a pneumatic impulse deicing method based on the conventional pneumatic deicing boot. This method’s simplified numerical simulation model was built using the commercial software ABAQUS to explore whether this method can deice. After that, experimental investigations were carried out in an artificial climate chamber to verify the deicing performance of specimens using this proposed method. Numerical and experimental results show that the pneumatic impulse deicing method could eliminate the ice layer with a smaller displacement and shorter time than the conventional pneumatic deicing boot. The ice layer’s thickening and inflation pressure enhancement benefit the deicing performance. Experiment results proved that the pneumatic impulse deicing method performs better under inflation pressures of 1.5 MPa and 2.5 MPa with an ice thickness of 6 mm or 8 mm.

Chloride-based deicing salt solutions have been contacted with concrete pastes containing slag cement at different conditions, such as slag replacement (20–80%), type (CaCl2, MgCl2, NaCl), and concentration (1 M–5 M) of the deicing salt, as well as temperature (ambient & −18 °C), and the extent of their reactions have been studied using XRD and ICP-OES. Also, solubility of Friedel salt (FS) has been measured in different types and concentrations of deicing salt solutions. It has been observed that the chemical deterioration arising from the formation and then dissolution of FS is more significant than the damage caused by the formation and expansion of oxychlorides in the pastes containing slag. While calcium oxychloride in its dried form can linger inside the paste for a long time, FS undergoes incongruent dissolution in CaCl2 and MgCl2 solutions and leaves the system. Presence of higher levels of AFm phases in pastes containing slag will further underscore this phenomenon. The extent of this chemical deterioration is relatively lower in NaCl solutions. Also, it was found that the nature of the chemical interaction changes with the concentration of the salt, as some disappeared phases might reappear and then disappear again. Using XRD and ICP-OES, this study provides a mechanistic understanding of salt-induced chemical deterioration in slag cement pastes by identifying phase-specific vulnerabilities and tracking the formation, transformation, and dissolution of key phases, such as Friedel’s salt and calcium oxychloride; additionally, the influence of various parameters have been studied, and chemical mechanisms have been proposed.

The icing of the overhead aluminum conductor has caused the conductor load to be too heavy or uneven, which results in huge accidents. The super-lubricated surface (SLIPS) shows great potential in anti-icing. Glaze ice is a common type of icing, and its damage to transmission lines is the most serious. However, the properties and influencing factors of anti-icing lubricated surfaces at glaze ice surroundings are rarely reported. In this study, the super-lubricated surface was prepared by the anodic oxidation method, and the anti-icing properties and influencing factors of surfaces were investigated in glaze ice surroundings. The results demonstrate that the SLIPS can decrease the icing amount, which is only 41% of the original aluminum surface. SLIPS exhibits excellent anti-icing performance in different environments temperatures and rainfalls. This study provides experimental guidance for the practice application of SLIPS in anti-icing aluminum conductors.

Transportation infrastructure such as concrete pavements, parapets, barriers, and bridge decks in cold regions are usually exposed to a heavy amount of deicing chemicals during the winter for ice and snow control. Various deicer salts can physically and chemically react with concrete and result in damage and deterioration. Currently, Idaho uses four different types of deicers during the winter: salt brine, mag bud converse, freeze guard plus, and mag chloride. The most often utilized substance is salt brine, which is created by dissolving rock salt at a concentration of 23.3%. Eight concrete mixtures for paving and structural purposes were made and put through a battery of durability tests. Following batching, measurements were made of the unit weight, entrained air, slump, and super air meter (SAM) fresh characteristics. Rapid freeze–thaw (F-T) cycle experiments, deicing scaling tests, and surface electrical resistivity testing were used to test and assess all mixes. Tests with mag bud converse, freeze guard plus mag chloride, and acid-soluble chloride were conducted following an extended period of soaking in salt brine. Two different structural mixtures were suggested as a result of the severe scaling observed in the structural mixtures lacking supplemental cementitious materials (SCMs) and the moderate scaling observed in the other combinations. The correlated values of the SAM number with the spacing factor have been shown that mixture with no SCMs has a spacing factor of 0.24, which is higher than the recommended value of 0.2 and concentrations of acid soluble chloride over the threshold limit were discernible. In addition, the highest weight of calcium hydroxide using the TGA test was observed. For all examined mixes, the residual elastic moduli after 300 cycles varied between 76.0 and 83.3 percent of the initial moduli. Mixture M5 displayed the lowest percentage of initial E (76.0 percent), while mixtures M1 and M2 showed the highest percentage of residual E (83.3 and 80.0 percent, respectively) among the evaluated combinations. There were no significant variations in the percentage of maintained stiffness between the combinations. As a result, it was difficult to identify distinct patterns about how the air content or SAM number affected the mixture’s durability. Class C coal fly ash and silica fume were present in the suggested mixtures, which were assessed using the same testing matrix as the original mixtures. Because of their exceptional durability against large concentrations of chemical deicers, the main findings suggest altering the concrete compositions to incorporate SCMs in a ternary form.

Phase equilibria are studied in sections of the systems NaCl–CO(NH 2 ) 2 –H 2 O, CaCl 2 –CO(NH 2 ) 2 –H 2 O, and NaCl–CaCl 2 –CO(NH 2 ) 2 –H 2 O at temperatures from 0 to –57°C. The features of the mutual influence of the components on the temperatures of the eutectics in the systems and on the deicing ability of urea–salt mixtures are determined. It is found that the introduction of urea into the systems CaCl 2 –H 2 O and NaCl–CaCl 2 –H 2 O gives rise to low-temperature eutectics with crystallization temperatures of –54 and –57°C, which are promising for the development of low-temperature deicing agents on their basis.

Chloride deicing salt stress usually coincides with the event of freeze–thaw, and the short-term adaptation of Dongmu-70 Secale cereale L. seedlings to these stresses was investigated in this paper. The chloride deicing salt and the freeze–thaw (FT) simulation experiments were carried out in the lab and alternation refrigerator. The changes of soluble sugar, soluble protein, relative conductivity (RC), malondialdehyde (MDA), and catalase (CAT) activity in seedlings were studied under freeze–thaw stress (10, 5, 0, − 5, 0, 5, and 10 °C) and 0, 200, 400, and 600 mmol L−1 of chloride deicing salt stress (CK, D1, D2, and D3). The results indicated that the content of physiological index in different treatment groups rose first and then decreased within a freeze–thaw cycle. During the recovery phase (T8: 24 h after freeze–thaw stress and T9: 6 days after freeze–thaw stress), there was significant difference either in MDA and CAT activity between D2 × FT and D2 or in RC, MDA, soluble sugar, and CAT activity between D3 × FT and D3. The seedlings showed different adaptability under different intensities of combined stress, and the sequence of the changes in physiological index can be patterned as D × FT > FT > D > CK. Freeze–thaw and chloride deicing salt complex stress exhibited a synergistic effect on the plant, which indicates that the snow-melting operation would be more harmful in spring and autumn to plants than in winter.