Conventional Curing Method Research Articles (Page 1)

Concrete's performance essentially depends on the hydration process, requiring adequate moisture and a controlled environment for curing. The traditional curing is challenging in water-scarce regions and in high-altitude areas. The self-curing concrete as an emerging sustainable and efficient alternative in conventional curing method scenarios and in challenging environments. Self-curing, or internal curing, is an innovative solution that ensures sufficient moisture for hydration and minimizes evaporation to enhance properties of concrete. This study explores the impact of various self-curing agents Superabsorbent Polymers (SAP), Polyethylene Glycol-400 (PEG-400), and Polyvinyl Alcohol (PVA) on the fresh and mechanical properties of self-curing concrete. The nine mix designs were developed, with self-curing agents incorporated at dosages of 1%, 2%, and 3% by weight of cement. The mechanical properties analysed include compressive strength, split tensile strength, and flexural strength, while workability was assessed using slump tests. The results expose that PEG-400 at 1% dosage the highest performance in terms of strength and workability, with compressive, tensile, and flexural strengths of 26.29 N/mm², 2.19 N/mm², and 2.27 N/mm², respectively. The SAP exhibited moderate performance with enhanced internal curing, while PVA offered balanced hydration benefits but lower strength compared to PEG-400. The increasing dosages of all agents led to a decline in mechanical performance due to reduced hydration efficiency and increased viscosity. The PEG-400 of optimizing self-curing agents to achieve a balance between curing efficiency and mechanical performance, contributing to the development of sustainable, high-quality concrete with reduced water consumption.

Aerated Concrete, or lightweight concrete, is primarily used in construction work for non-load-bearing structures and is typically produced with cement as a primary binding material. Cement production accounts for 7 to 8% of the environmental CO2 emissions. Furthermore, the dumping of industrial waste and the consumption of aggregates disrupt the environment and ecosystem. This research aims at developing sustainable AC by partially substituting cement with FA and hill sand with IRS while maintaining the fundamental properties of aerated concrete. The study was conducted to investigate the physical and chemical properties of the materials and the physical and mechanical properties of aerated concrete. Variations of fly ash, i.e., 10%-70%, were incorporated as a CRM to get optimum FA usage in terms of density and compressive strength. Optimum FA was incorporated as CRM and IRS as sand replacement, used in four variations, i.e., 10% - 25%. Specimens were cured using the conventional curing method and autoclaving for NAAC and AAC, considering both manufacturing processes, CO2 emissions and time limitations in respective curing methods. Conventional curing was performed at 7, 14, and 28 days, while autoclaving was performed at various pressures, i.e., 0.5 bar, 1 bar, and 1.5 bar. The optimum compressive strength of AAC and NAAC was achieved when 20% of the IRS and 50% of FA were replaced with hill sand and cement, respectively, for both AAC and NAAC. Additionally, approximately 32% and 39.3% of CO2 emissions were reduced with 50% FA and 20% river sand replacement with cement for AAC and NAAC specimens. Although AAC demonstrated slightly lower water absorption due to densification through autoclaving, NAAC performed satisfactorily in offering a more cost-effective and energy-efficient alternative.

The conventional curing methods pose a significant environmental threat due to the use of toxic vulcanizing agents, the release of irritating volatile organic compounds, and the difficulties in recycling end-of-life rubber products. This work demonstrates a catalyst-free, facile, and eco-friendly crosslinking strategy based on the reaction between epoxy-functionalized ethylene-propylene-diene monomer (EEPDM) and dicarboxylic acids. The EEPDM was synthesized via a reusable reaction-controlled phase-transfer catalyst. Then, EEPDM could be effectively crosslinked by dicarboxylic acids without additional additives. The increased acidity of dicarboxylic acids could be conducive to improving the crosslinking rate. Moreover, the curing mechanism and the nature of the crosslinks were investigated, which is crucial for the recyclability of rubbers. The dicarboxylic acid-cured EEPDM exhibited undesirable side reactions, the extent of which showed a positive correlation with the acidity of carboxylic groups. This phenomenon could be primarily attributed to acid-catalyzed self-polymerization via epoxide ring-opening mechanisms, which would be detrimental to the reprocessability. Due to the formation of thermally stable ether linkages, the crosslinked EEPDM exhibited enhanced thermal-oxidative aging behavior. Hence, we envision that this catalyst-free, high-efficiency crosslinking strategy may offer a promising bridge between sustainable modification and high-performance for epoxy-functionalized rubbers, holding potential application in eco-friendly, low-odor automotive sealing strips.

Rapid and scalable production of high‐performance composites remains a key challenge in achieving sustainable manufacturing. Here, Exo‐press frontal polymerization (EPFP), a novel and transformative method for manufacturing fiber‐reinforced thermoset polymer composites, overcoming energy efficiency, scalability, and curing complex geometries, is introduced. Unlike conventional curing methods that require prolonged processing times and high energy, EPFP utilizes exothermic heat to reduce curing time from hours to minutes with minimal external energy. Combining exothermic heat with press molding, the novel EPFP enables the efficient fabrication of complex geometries, such as airfoil skin sections, with high fiber volume fractions (above 60%). In addition, EPFP is compatible with commercial off‐the‐shelf epoxy by integrating frontal resin, showcasing its versatility and adaptability for diverse industrial applications. Composites manufactured using EPFP exhibit superior thermomechanical properties while significantly reducing energy consumption by 80% and production costs by 40%. This makes it a sustainable and efficient solution for polymer composites manufacturing.

This study compared the effects of open-fire flue-curing and conventional curing methods on the aroma and chemical composition of K326 tobacco leaves, aiming to reveal the molecular mechanisms of aroma formation during open-fire flue-curing. The results showed that after curing, the leaves from conventional curing appeared orange-yellow, while those from open-fire flue-curing exhibited a brownish color. Sensory evaluation indicated that the leaves absorbed the combustion aroma of pine wood, resulting in an elegant woody fragrance, enhanced pungency, and a harmonious balance between the pungency and woodiness, with a rich aroma and prominent flavor. Physical and chemical analyses indicated that, Unlike conventional curing, the rate of moisture loss in open-fire flue-cured leaves was slower. Between 38 °C and 42 °C, the moisture content of conventionally cured leaves decreased by 9.96%, while that of open-fire flue-cured leaves decreased by only 5.18%. Meanwhile, during this phase, the activity of polyphenol oxidase (PPO) in open-fire flue-cured leaves was significantly higher than in conventionally cured leaves. Phenolic compound analysis showed that, Compared to conventional curing, the scopolamine content in open-fire cured leaves decreased by 33.85%, while the contents of neochlorogenic acid, chlorogenic acid, and rutin increased significantly to 1.63, 11.59, and 16.46 mg/g, respectively. An integrated metabolomics and proteomics analysis identified phenylalanine metabolism and amino acid degradation pathways as the central mechanisms driving aroma differentiation. Specifically, key enzymes and proteins in the phenylalanine metabolism pathway were significantly upregulated, promoting the synthesis of phenylalanine and its derivatives. Meanwhile, the degradation of lysine resulted in the conversion of fewer nitrogen-containing compounds in the open-fire flue-cured leaves. These synergistic effects enhanced the production of secondary metabolites, which were further released and transformed during the curing process, ultimately improving the aroma quality of the tobacco leaves. This study not only deepens the scientific understanding of aroma formation during open-fire flue-curing, but also provides theoretical support for the precise regulation and directional synthesis of characteristic aromas, offering feasible strategies to optimize curing processes and enhance the industrial quality of tobacco.Graphical

Frontal polymerization (FP) offers an efficient and energy-saving alternative to conventional curing methods for epoxy resins. In this study, a transient thermo-chemical coupled heat-transfer model (V-model) was developed using temperature-dependent thermophysical properties. Curing kinetics parameters were first determined by fitting data from non-isothermal differential scanning calorimetry of a BADGE-based resin. Compared to a constant-property model, accounting for changes in thermal conductivity and specific heat capacity significantly improved the accuracy of the predicted temperature profiles, aligning more closely with experimental observations. The validated V-model was then extended to evaluate the impact of boundary materials with different thermal conductivities on FP behavior. Experiments confirmed that high-conductivity boundaries facilitate preheating of unreacted resin, thereby promoting faster polymerization-wave propagation. Meanwhile, insulating boundary materials minimize heat loss, sustaining the FP reaction. This combined computational–experimental approach provides deeper insights into the heat-transfer mechanisms governing epoxy resin FP and guidance for optimizing industrial process parameters.

This study investigates the effectiveness of solar energy-based heat treatment for concrete and mortar as a sustainable alternative to conventional curing methods. The approach aims to enhance early-age strength while reducing energy consumption, lowering production costs, and minimizing environmental impact. The acceleration of concrete and mortar hardening contributes to early-age strength development, which is beneficial for the prefabricated construction industry. Two treatment cycles were conducted: The first was: A 10 hours cycle in a solar dryer (SD) and an oven, reaching a maximum temperature of 55°C, with an average relative humidity of 60%. The second was: A 12 hours cycle in a solar greenhouse (SG), achieving 60°C with 50% relative humidity. The results of the tests were compared with those of the control specimens, hardened in at 25°C, 50% of relative humidity. The heat treatment significantly enhanced early-age strength development. On day one, mortar flexural strengths in SD, oven, and SG reached 25%, 25%, and 18%, respectively, of 28 days control specimen strength. However, treatment conditions did not significantly affect flexural strength at 120 days, with treated specimens exhibiting strengths comparable to control specimens. Moreover, these treatments lower concrete production costs while reducing CO₂ emissions by approximately 214.6 g/m³, underscoring their positive environmental impact.

Comparison of the efficacy of carbonation and conventional curing for remediation of copper-contaminated soils by ladle slag

Performance evaluation of high-performance concrete mixes incorporating recycled steel scale waste as fine aggregates

Heat-activated polymethyl methacrylate (PMMA) is the most common and widely accepted denture base material. Two important drawbacks are the development of denture stomatitis and the high incidence of fracture of denture bases. The present study investigated the effect of adding 0.2% by weight of silver nanoparticles (AgNps) and using the autoclave method of terminal boiling on the flexural strength of heat-activated PMMA denture base resin. A total of 40 samples of heat-activated PMMA blocks were divided into four groups, with 10 samples (n = 10) in each group. Group 1 consisted of unmodified heat-activated PMMA resin (PMMA-1) polymerized by the conventional method of terminal boiling (conventional curing); Group 2 consisted of 0.2% by weight AgNPs added to heat-activated PMMA resin (PMMA-2) polymerized by conventional curing; Group 3 consisted of PMMA-1 polymerized by the autoclave method of terminal boiling (autoclave curing); and Group 4 consisted of PMMA-2 polymerized by autoclave curing. The flexural strength was tested using a universal testing machine. Descriptive statistics were expressed as mean ± SD and median flexural strength. Kruskal-Wallis ANOVA with Mann-Whitney U post hoc test was applied to test for statistical significance between the groups. The level of significance was set at p<0.05. The results showed a statistically significant reduction in flexural strength in Group 2 compared to Group 1. The samples from Group 4 showed a statistically significant increase in flexural strength compared to Group 2. The Group 4 denture base had the highest flexural strength (115.72 ± 7.27 MPa) among the four groups, followed by Group 3 (104.16 ± 4.85 MPa). The Group 1 samples gave a flexural strength of 101.45 ± 3.13 MPa, and Group 2 gave the lowest flexural strength (85.98 ± 3.49 MPa) among the four groups tested. The reduction in flexural strength of the heat-activated PMMA denture base after adding 0.2% by weight of AgNP as an antifungal agent was a major concern among manufacturers of commercially available denture base materials. It was proved in the present study that employing the autoclave curing method of terminal boiling for the polymerization of 0.2% by weight of AgNp-added heat-activated PMMA denture base resulted in a significantly higher flexural strength compared to the conventional curing method of terminal boiling for polymerization. Unmodified heat-activated PMMA gave higher flexural strength values when polymerized by autoclave curing compared to the conventional curing method of terminal boiling.

Comparative life cycle environmental assessment of recycled aggregates concrete blocks using accelerated carbonation curing and traditional methods

Effect of curing regime on the immobilization of municipal solid waste incineration fly ash in sustainable cement mortar

Effects of content and length/diameter ratio of PP fiber on explosive spalling resistance of hybrid fiber-reinforced ultra-high-performance concrete

Strength and durability of self-curing concrete developed using calcium lignosulfonate

Aerated concrete is made by introducing gas into concrete, the number dependent upon the necessities for strength. One methodology to attain this can be by utilizing Al Powder that reacts with the lime made upon association of the cement. The aim of the present study was to research the comparison between the steam curing method and the conventional curing method. The results specified that a rise in powdered aluminium content caused a decrease within the compressive strength, and an increase in change in volume when the aluminium powder is increased.

Conventional materials are replaced by polymer composites in every field due to its wide applications and its ease to custom make the required properties for the purpose it is designated for. Structural applications require higher strength, and this is achieved only by better curing of polymer composites during its processing. Elevated temperature curing helps to improve cross linking of polymers. In this regard infrared radiation curing is one of the methods adopted in the recent days for elevated temperature curing of polymer composites. It is one of the efficient ways of curing polymer matrix composites. In this paper Infrared radiation heat transfer studies of polymer composite is reviewed and compared its efficiency with the hot air or conventional curing method. Further modelling is carried out to prove the efficacy of the same.

Numerous researchers have attempted to improve the mechanical properties of glass ionomer cement since 1972. In this study, ultrasonic curing treatment was introduced during the mixing of glass ionomer cement (GC Fuji IX) to facilitate intimate mixing, compaction and adaptation of residual glass particle which consequently improves densification of the material. To assess the influence of ultrasonic treatment on the microhardness of glass ionomer cement (GC Fuji IX) and compare it with the conventionally cured method. A total of 40 specimens (2 × 2 mm) were fabricated and equally divided into two groups: Group I (conventional curing method) and Group II (ultrasonically cured). For Group II, an ultrasonic scaler was used which provides energy to ensure proper mixing of material without leaving any air bubbles or unmixed particles. Vicker's hardness test was employed to generate the average microhardness values by making three indentations at different points on each specimen. Statistical Package for Social Sciences (SPSS) Version 17 was used, employing independent samples T test to compare the difference in microhardness values between two curing groups. The average surface hardness value for conventional cured GIC was 62.21 ± 13.61 while ultrasonically cured GIC exhibited a higher mean microhardness value of 66.37 ± 12.83. Additionally, the average microhardness values produced by the two groups showed statistically significant differences (p value < 0.035). Ultrasonic excitation treatment leads to intimate mixing and accelerated hardening of glass ionomer cement thereby enhancing its microhardness and reducing early weakness.

This study evaluated the effects of the light curing methods and resin composite composition on composite polymerization contraction behavior and resin composite adaptation to the cavity wall using μCT-3D visualization analysis and dye penetration test. Cylindrical cavities were restored using Clearfil tri-S Bond ND Quick adhesive and filled with Clearfil AP-X or Clearfil Photo Bright composite. The composites were cured using the conventional or the slow-start curing method. The light-cured resin composite, which had increased contrast ratio during polymerization, improved adaptation to the cavity wall using the slow-start curing method. In the μCT-3D visualization method, the slow-start curing method reduced polymerization shrinkage volume of resin composite restoration to half of that produced by the conventional curing method in the cavity with adhesive for both composites.μCT-3D visualization method can be used to detect and analyze resin composite polymerization contraction behavior and shrinkage volume as 3D image in the cavity.

Background: the common problem in prosthodontics is a fracture of the denture base and it represents an annoyance for the dentists. Therefore, the option of increasing repair strength using new reinforcement materials is of great interest to prosthodon- tists. The purpose of this study was to assess the effects of using a special type of acrylic o-cry1 in repair instead of heat cure acrylic resins and different surface treatments on impact bond strength using Ivomet and conventional curing methods. Materials and Methods: One hundred thirty specimens of heat acrylic resins were constructed. There are 2 main groups accord- ing to curing methods (Ivomet and conventional method curing). For each group, there were 6 groups according to the surface treatments used (untreated, monomer, thiner, zirconium oxide, glass fiber and butt joint with monomer) as well as control group. Results: The study showed that the control group had a higher value of impact strength than other groups which were cured by conventional method. For Ivomet curing, the butt joint with monomer and glass fiber groups improved the impact bond strength in comparison to other groups. Conclusion: the butt joint with monomer treatment and glass fiber groups have improved the impact strength of the repaired acrylic resins when using Ivomet compared with other groups. On the other hand, the use of thiner and zirconium oxide reduced the impact bond strength when using the conventional curing method. The use of Ivomet device in curing samples improved the impact strength of acrylic repaired with O-cry1.

Availability of water plays an essential role in the hydration of ordinary portland cement. At low water-to-cement (w/c) ratios, for example, hydration processes can rapidly deplete water. The increased demand for more water exacerbates surface tension-induced stresses within fine capillary pores, which causes shrinkage of the cement paste. This phenomenon, termed autogenous shrinkage, is often prevented with sufficient curing, namely by keeping the surface of the concrete continuously wet. However, such conventional curing methods are not sufficient for ultra-high-performance concretes, which are produced with very low w/c ratios. In these applications, autogenous shrinkage is mitigated via the use of internal curing approaches, either by inclusion of prewetted lightweight aggregates or superabsorbent polymers (SAPs). SAPs are ultra-hydrophilic polymer networks capable of absorbing 100,000% of their dry weight in water. A variety of acrylic-based monomers are typically employed in the preparation of SAPs, as are a number of aggressive solvents and time- and energy-intensive polymerizations. This paper presents recent experimental efforts on synthesizing and characterizing superabsorbent polymers from biorenewable resources and principles of green chemistry. In this work, the chemical synthesis and physical swelling of superabsorbent biopolymers are investigated in (a) water and (b) synthetic concrete pore solutions. Results demonstrate that biobased SAPs that absorb in excess of 20,000% their weight in water can be synthesized using ambient-condition polymerizations and green solvents, thus offering a potential biobased solution to successfully mitigating autogenous shrinkage in ordinary portland cement paste and mortars.