สมรรถนะทางวิศวกรรมของผิวทางแอสฟัลต์คอนกรีต Duopave

This research investigates the probability of using asphalt concrete AC Duopave as a new pavement and repaired pavement. The studied aggregate was limestone, which is locally available in Thailand. The engineering behavior of AC Duopave was compared with that of Marshall’s asphalt concrete, which is a standard asphalt concrete pavement of rural roads in Thailand. Test results showed that the engineering properties (indirect tensile strength, resilient modulus, indirect tensile fatigue and dynamic creep) of AC Duopave were superior to those of Marshall’s asphalt concrete for the same air voids. The air voids affected engineering properties of AC Duopave: the indirect tensile strength, resilient modulus and indirect tensile fatigue of AC Duoapave increased while the dynamic creep of AC Duoapave decreased as the air voids decreased

Self-compacting steel fibers reinforced geopolymer: Study on mechanical properties and durability against acid and chloride attacks

This study aimed to investigate the effects of steel fibers on the properties of self-compacting geopolymer (SCG), including flowability and fillability, compressive and flexural strength, and durability against harmful chemical substances such as acids and chloride. In the first stage, the study involved determining the optimum fiber content for geopolymer that meets the criteria for self-compacting concrete. The second stage involved investigating the mechanical properties and durability of self-compacting fiber-reinforced geopolymer (SCFRG). For SCG, the binder phase consisted of fly ash and slag at different proportions, while for SCFRG, the geopolymer was mixed with hooked-end steel fiber at 0.5–1.5% by volume fractions. The study found that adding 0.5% to 1.5% steel fibers by volume fraction to create self-compacting fiber-reinforced geopolymer (SCFRG) improved compressive strength by 8.7%, toughness by 88%, and residual strength by 83.7%. However, it slightly reduced slump and filling ratio while increasing T50. Both SCG and SCFRG's durability were assessed by immersing samples in 5% concentration chemical solutions, resulting in weight loss to varying degrees depending on the type of chemical. In terms of weight loss, immersion in 5% sodium chloride showed no effect, while immersion in 5% magnesium sulfate and 5% sulfuric acid resulted in a reduction in weight compared to samples cured in ambient conditions. Additionally, SCFRG samples submerged in MgSO4, H2SO4, and NaCl demonstrated relatively stable compressive strength when compared to ambient samples. The addition of steel fibers to SCG reduced the chloride penetration depth and diffusivity, indicating better resistance to chloride ion penetration. In summary, the study demonstrated that although the addition of steel fibers decreased flowability and fillability, it potentially improved the mechanical and durability properties of self-compacting geopolymer

Use of viscoelastic polymer sheet as an acoustic control treatment in ceramic tiles to improve sound insertion loss

Ceramic tiles are commonly used in non-structural components of a building such as walls, partitions, floors, and roofs. However, due to their high surface hardness and density, ceramic tiles are not an ideal soundproof material. To improve the sound properties, this study introduced the use of a viscoelastic polymer sheet (VPS) as an acoustic control treatment. The VPS was attached to ceramic tiles in 4 different patterns: X, Cross, Corner, and Strip. The ceramic tiles with VPS were tested for the damping property and sound insertion loss (IL) and then compared to the ones without VPS. Results indicated that the attachment of VPS improved the damping property of the ceramic tiles. All tiles with VPS exhibited higher damping loss indexes than the ones with no VPS. The highest damping loss index of 0.017–0.018 was observed in the specimens with VPS in X and Cross patterns. In the case of IL, the performance of all ceramic tiles was indifferent when tested at sound frequencies smaller than 1000Hz. At the sound frequencies above 1000Hz, the best performance was observed in the specimen with VPS in the Cross pattern, followed by X, Strip, and Corner patterns, respectively. This concluded that the use of VPS can improve the damping property of a ceramic tile which also leads to the improvement in sound insertion loss

Composite carbon materials from winery composted waste for the treatment of effluents contaminated with ketoprofen and 2-nitrophenol

The present work consisted of preparing and characterizing composite carbon materials (WRCC) from raw winery residues (WR) activated with zinc chloride to produce a carbon adsorbent. The WRCC was used for the adsorption of emerging contaminants in aqueous media. The WRCC presented a morphology with favorable characteristics for the adsorption process, giving an abundant porous structure with pores of different sizes. The results show the WRCC's effectiveness, presenting surface area values (227 m2 g-1) and total pore volume (0.175 cm3 g-1). The general order kinetic model predicted the experimental curves sufficiently. The Sips model better described the two adsorbates' equilibrium data, with maximum adsorption capacities of 376.0 and 119.6 mg g-1 for 2-nitrophenol and ketoprofen, respectively. The WRCC carbon material was also highly efficient, with maximum removal of 81.4% and 94% in 1000 mg L-1 of the compounds 2-nitrophenol and ketoprofen. Finally, the prepared material has essential characteristics that make it an efficient adsorbent in treating effluents with emerging contaminants

Numerical analysis of bearing reinforcement earth (BRE) wall

This paper presents a numerical simulation of the bearing reinforcement earth wall by PLAXIS 2D. The bearing reinforcement was regarded as a cost-effective earth reinforcement. The model parameters for the simulation were obtained from the conventional laboratory tests and back analyses from the laboratory pullout tests of the bearing reinforcement. The simplified method for modeling the bearing reinforcement, which converts the contribution of friction and bearing resistance to the equivalent friction resistance, is introduced. This method is considered to be acceptable and practical in working state with sufficient factor of safety and small pullout displacement. The bearing reinforcement is modeled as the geotextile and the equivalent friction resistance is represented by the soil/reinforcement interface parameter, R, which was obtained from a back analysis of the laboratory pullout test results. The R values are 0.65 and 0.75 for the bearing reinforcement with 2 and 3 transverse members, respectively. The change in bearing stresses, settlements, lateral earth pressures and tensions in the reinforcements during and after construction is simulated. Overall, the simulated test results are in good agreement with the measured ones. The simulated results show that the BRE wall behaves as a rigid body, retaining the unreinforced backfill. The simulated bearing stress presents a trapezoid distribution shape as generally assumed by the conventional method of examination of the external stability of MSE walls. The simulated settlement is almost uniform due to a high stiffness of the rigid foundation and the bearing reinforcements. The maximum lateral movement occurs at about the mid-height of the wall, resulting in the bi-linear maximum tension plane. The knowledge gained from this study can be applied to other BRE walls with different wall heights, foundations and features of bearing reinforcements