Key Engineering Materials Vol. 1053

Abstract: This paper aimed to develop low temperature firing of clay tiles. Waste glass had been reutilized for lowering the firing temperature of clay bodies. Alternative materials were also used in this study. They consisted of sediment soil, local volcanic soil, and local illite clay. In addition, boric oxide was also used as a sintering aid in this study. A total of 36 formulations were prepared, categorized into three main groups (A, B, and C). The samples were prepared by uniaxial pressing at 100 bars and then fired at 800 °C and 850 °C to evaluate their physical and mechanical properties. The results indicated that formulation B12 (consisting of 75% CGC, 25% SVS, and 2% boric oxide) exhibited the highest flexural strength (26.05 MPa) and the lowest water absorption (0.26%) at 850 °C. Additionally, both B12 and C12 formulations fired at 800 °C also achieved the requirements of the Thai Industrial Standard (TIS 2508-2555) for types BIIb and BIII, respectively. Microstructural analysis by Scanning Electron Microscopy (SEM) and phase identification through X-Ray Diffraction (XRD) revealed that the crystalline phases cristobalite, wollastonite, and albite as well as amorphous glassy phases play key roles in improving the density and mechanical properties of ceramic bodies. It can be concluded that the combination of industrial waste and locally sourced natural clays in Thailand enables the development of eco-friendly clay tiles with suitable properties at low firing temperatures, in compliance with national ceramic product standards.

Abstract: Increasingly accumulated as waste each year and depletion of fossil fuel, this leads to challenge work for alleviating this problem. Therefore, this research aimed to utilize clear glass cullet, for developing non-fired wall tiles. It need not to consume energy for firing. The base formulation of the experiment was composed of ordinary Portland cement (OPC), lateritic soil (LS), crushed limestone dust (CLD), and river sand (RS). The experimental design was divided into four groups: Group A was the control formulation, while Groups B, C, and D incorporated glass cullet as a partial replacement for OPC, LS, and CLD, respectively, at different levels. After mixing, the specimens were formed under a uniaxial pressure of 100 bar and subsequently cured at room temperature for 7 and 21 days. The properties evaluated included flexural strength, water absorption, linear shrinkage, and bulk density, with reference to the Thai Industrial Standard (TIS) 2508–2555, type BIII. The results indicated that the replacement of clear glass cullet in OPC, LS, and CLD yielded an experimental formulation that satisfied the standard requirements. Specifically, formulation C3, consisting of 15% CGC, 22.5% OPC, 40% LS, 15% CLD, and 7.5% RS, achieved a flexural strength of 12.27 MPa and a water absorption of 13.92%. This formulation was identified as the optimum mix for the 21-day curing age because it satisfies the requirements of the Thai Industrial Standard (TIS). In addition, a microstructure analysis of selected specimens was conducted. It was found that formulation C3 revealed the highest formation of calcium silicate hydrate (CSH) gel, which corresponded to its high bending strength.

Abstract: This study investigates CO₂ sequestration in high-calcium fly ash (HCFA) geopolymer cement through combined heat and CO₂ curing. Class C fly ash from the lignite-fired power plant was activated with 10 M NaOH (L/B = 0.40). Two curing regimes were applied: heat curing at 60 °C for 24 h (Typical GP) and heat curing followed by CO₂ curing at 15 % v/v for 24 h (CO₂ Curing GP). CO₂ curing increased the average compressive strength by 7.16 %, from 15.75 to 16.87 MPa. Phenolphthalein testing revealed a ~4.3-fold increase in carbonation area and a greater average penetration depth, from 1.9 to 7.9 mm, compared with the control. XRD confirmed calcite as the main carbonation product, along with hematite, magnetite, sodium sulfate, and ye’elimite. This work represents an initial step toward applying industrial CO₂-rich gas for geopolymer curing in Thailand, offering dual benefits of improved mechanical performance and significant CO₂ capture potential for sustainable construction.

Abstract: Concrete cracking behavior under distributed forces is influenced by several factors such as material properties, crack initiation, propagation, and the impact of external loads. This paper aims to explore the relationship between concrete surface conditions and concrete material shape and concrete crack patterns under compressive loads. The literature review method uses general search queries with the most important keywords from academic databases, from reputable source Scopus and Science Direct. Following is an example of a query applied in a database for extraction: “rough AND surface AND contact”; “fracture AND mechanics AND of AND concrete”; “pressure AND test AND system”; “concrete AND crack AND pattern AND modeling”; “concrete AND crack AND pattern AND concrete AND compression AND test”; “surface AND contact AND in AND compression AND test”; “surface AND contact AND in AND concrete AND compression AND test”. The literature is limited from 2000 to 2025, obtaining the following three general topic groups: “rough surface contact” with 7347 articles, “compression testing system” with 2108 articles and “concrete crack mechanics” with 4307 articles. The resultss is then further filtered out by applying four groups: “concrete crack pattern in compression test” with 35 articles, “concrete crack pattern modeling” with 60 articles, “surface contact in compression test” with 31 articles and “surface contact in concrete compression test” with 5 articles. A total of 137 identified articles were entered into the Mendeley database in .ris format and then evaluated them using Vosveiwer application to see the most frequently appearing and relevant keyword relationships for the proposed research. Mapping results acwuires keywords “numerical simulation”, “concrete”, “fracture” and “crack propagation” most frequently occurring and interconnected. A systematic sythesis are then implemented and compiled for a comprehensive review article relates in a meningful literature.

Abstract: Offshore platforms are marine buildings commonly used for oil and gas exploitation activities. In general, reported failures in the life of offshore structures are fatigue failures resulting from environmental factors, such as random and continuous wave loads. In addition to environmental factors, the determination of the dimensions and thickness of the structure also plays an important role in increasing its strength. This study used Finite Element software with in-place analysis to calculate the strength and deterministic fatigue method for fatigue life analysis. This study aims to analyze the effect of the thickness of the jacket structure members on the strength and fatigue life. The results of the analysis showed that there was an increase in maximum UC and a decrease in fatigue life due to a reduction in thickness in the jacket members, where the initial model had a maximum UC of 0.64 with a fatigue life of 1285.83 years, while the 10% thickness reduction had a UC of 0.71 with a fatigue life of 552.07 years, a thickness reduction of 20% had a UC of 0.79 with a fatigue life of 213.80 years, a thickness reduction of 30% had a UC of 0.90 with a fatigue life of 62.14 years and a thickness reduction of 40% had a UC of 1.04 with a fatigue life 14.71 years. This research is expected to be a reference in designing the jacket structure to determine the optimal dimensions according to the planned fatigue life.

Abstract: This study presents a comparative evaluation of four steel beam-to-column connection configurations—Conventional (CONV), Cover Plate (CP), Reduced Beam Section (RBS), and a hybrid Reduced Beam Section with Cover Plate (RBSCP)—under cyclic loading conditions, with particular emphasis on hysteresis behavior and energy dissipation capacity. Finite element simulations were performed up to 6% story drift to evaluate each model’s performance against the seismic demand limits prescribed in ASCE/SEI 41-17. All configurations demonstrated adequate ductility for moderate to severe seismic events. The CONV model underperformed in both energy dissipation and stiffness retention, producing narrower hysteresis loops and exhibiting earlier stiffness degradation. In contrast, the CP connection achieved the highest energy dissipation and moment strength at all drift levels, attributed to the increased flange stiffness from the cover plates. The RBS model exhibited stable, well-balanced hysteresis loops with slightly lower strength but effective energy dissipation, benefiting from the intentional relocation of the plastic hinge away from the column face. The RBSCP connection combined the advantages of strength and ductility, sustaining broad and stable hysteresis loops with minor asymmetry between the positive and negative directions. Although it did not surpass CP in peak strength, RBSCP offered a well-balanced seismic performance. Envelope curve analysis revealed distinct differences in stiffness and degradation patterns. These findings highlight the potential of hybrid configurations such as RBSCP, with further geometric optimization recommended to enhance consistency and reliability.

Abstract: In this study, the vegetable waste-derived paper was developed from vegetable waste-derived fiber and Mahachanok mango seed-derived activated carbon to extend the shelf life of Golden Nam Dok Mai mangoes. Vegetable waste was subjected to alkaline processing using sodium hydroxide to extract plant-based fibers, which were then formed into paper sheets. Activated carbon, derived from Mahachanok mango seeds by carbonization at 450°C and activated by potassium permanganate (KMnO₄), was incorporated into the vegetable waste-derived paper to enhance ethylene adsorption efficiency. Three formulations of ripening delay paper were prepared: paper without activated carbon, paper containing 10 g of activated carbon, and paper containing 20 g of activated carbon. The physical properties of the papers were evaluated in terms of tensile strength and water drop absorption. The vegetable waste-derived paper incorporated with 20 g activated carbon showed the highest performance among the developed papers (1.20 ± 0.24 MPa and 0.74 seconds, respectively). Application tests on Golden Nam Dok Mai mangoes showed that the 10 g activated carbon formulation was the most effective in preserving flesh color, maintaining firmness, and balancing total soluble solids (TSS) and titratable acidity (TA), indicating a delayed ripening process. Therefore, ripening delay paper synthesized from vegetable fiber and supplemented with 10 g of activated carbon per 1 kg of fruit was proven to effectively prolong mango shelf life by up to 3 days, demonstrating its potential as a biodegradable solution for postharvest quality preservation.

Abstract: The growing demand for sustainable packaging materials has driven research toward the development of biodegradable polymer-based films with enhanced functional properties. This study aims to characterize the biodegradation properties of PVA/AKD/ZnO using soil burial method. PVA/AKD/ZnO films were prepared by solvent casting method at concentrations of 10 w/v %, 3 wt%, and 1 wt%, respectively. The films were subjected to soil burial degradation for 15, 30, 45, and 60 days, and their degradation behavior was monitored over time. The surface morphology, chemcial interactions, and thermal properties was determined by comparing the initial and post-degradation sample behavior. The outcomes of this study are anticipated to support the development of biodegradable materials for active food packaging applications.

Abstract: This study developed a functional bioactive film based on fish gelatin (FG) with astaxanthin-rich oil (Ax) extracted from black tiger shrimp (Penaeus monodon) byproducts using natural deep eutectic solvents (NADES) and ultrasond-assited extraction. The extracted oil showed high antioxidant activity (80.24% DPPH scavenging) and good oxidative stability (PV = 3.12 mEq/kg) within the GOED limit. Fish gelatin films with different Ax concentrations (0.25–1%) were characterized for color, transparency, moisture content, solubility, thickness, and mechanical properties. Results showed that Ax increased film thickness and mechanical properties while decreasing solubility and moisture content. Higher Ax levels similarly increased opacity and redness due to astaxanthin’s carotenoid pigments. FTIR analysis confirmed the molecular interaction between gelatin and Ax, especially hydrogen bonding and ester linkages. These results demonstrate that incorporating astaxanthin-rich oil into fish gelatin film can enhance its functional properties for use in bioactive packaging applications.