Buton Rock Asphalt (BRA) shows potential as a sustainable asphalt mixture, but its high stiffness limits performance. This study evaluates performance improvements in BRA through softening with waste engine oil (WEO) and elastomeric reinforcement with nano crumb rubber (NCR), focusing on rheological response and rutting resistance under aging conditions. Modified BRA mixtures with 15 % WEO and 1.5 %-2.0 % NCR were tested using a Dynamic Shear Rheometer under Pressure Aging Vessel (PAV), Resilient Modulus, and Wheel Tracking Machine conditions. Data analysis employed mechanistic methods, including Modulus Decay, Response Surface Methodology (RSM), and the Multivariate Rational Response Surface Model (MRRSM). Results indicate that increasing temperature decreases the Resilient Modulus across all mixtures. By analyzing Modulus Decay and changes in permanent deformation, the need for NCR additives in aggregate asphalt mixtures can be designed. Under PAV conditions, the Resilient Modulus is primarily influenced by the binder rheological parameter |G|& sdot;sin(delta). RSM and MRRSM analysis demonstrate that increasing binder stiffness at extreme temperatures does not necessarily enhance rutting resistance. The integration of WEO and NCR into BRA significantly improves mechanistic performance, a MRRSM serving as a quantitative method for performance-based asphalt pavement design under aging and extreme temperatures
Abstract Oxidative aging reduces the rheological performance of asphalt, resulting in increased stiffness and decreased viscoelasticity. Buton stone asphalt is a natural asphalt whose use requires a softening process. Natural asphalt softeners affect the properties of natural asphalt in asphalt-concrete mixtures. This study examined the use of used engine oil combined with crumb rubber and fly ash additives, which were reduced in size to the nanoscale and then tested using a dynamic shear rheometer to determine short- and long-term aging processes at 25–60 °C. The characteristics of the mixtures with these additives were evaluated in terms of the rut stiffness and fatigue resistance using the power law rheological model, which is a development of the power law. The results revealed a fourfold increase in stiffness. Moreover, the addition of nanoadditives increased the resistance to aging. A mixture of buton stone asphalt with nano crumb rubber and nano fly ash resulted in changes in the stiffness values and structural resistance to thermal and oxidative influences. Negative temperature coefficient values (0.141–0.127) indicate thermoplastic properties of the material, whereas positive aging coefficients (0.675–1.219) indicate increased stiffness due to oxidation. Multivariate polynomial regression yielded R2 values of 0.962–0.987. Validation against actual data showed the evolved power law rheological model had very small deviations at all temperatures and aging conditions. The power law significantly increased with increasing temperature, aging, and additive addition.
Industrialisasi otomotif modern mendorong penggunaan komposit polimer teknik untuk mengurangi bobot kendaraan dan meningkatkan ketahanan komponen pada suhu tinggi. Penelitian ini mengevaluasi kinetika degradasi termo-oksidatif dan ketahanan thermal aging PA6-GF30, PA66-GF30, dan PBT-GF30. Accelerated thermal aging dilakukan sesuai ASTM D3045 pada 130, 150, dan 170 °C selama 0–1000 jam. Sifat mekanik diuji berdasarkan ASTM D638, sedangkan perubahan fisikokimia dan morfologi dianalisis menggunakan DSC, TGA, dan SEM. Hasil menunjukkan strain at break lebih sensitif terhadap degradasi dibandingkan tensile strength. Pada 170 °C selama 1000 jam, retensi tensile strength PA6-GF30, PBT-GF30, dan PA66-GF30 masing-masing 92,7%, 87,3%, dan 85,6%. Pemodelan orde kesatu–Arrhenius menghasilkan energi aktivasi 52,49 kJ/mol untuk PA6-GF30 dan 36,04 kJ/mol untuk PA66-GF30, sedangkan PBT-GF30 menunjukkan perilaku non-Arrhenius. Proyeksi RTI pada retensi 50% selama 5.000 jam masing-masing mencapai 187,3 °C, 169,8 °C, dan 161,0 °C. Analisis DSC, TGA, dan SEM mengonfirmasi embrittlement, penurunan stabilitas termal, serta kerusakan mikrostruktur. Secara keseluruhan, PA6-GF30 menunjukkan ketahanan penuaan termal dan reliabilitas umur pakai terbaik untuk aplikasi otomotif under-the-hood bersuhu tinggi.
Relocation of two 60 t gas compressor sets in an operating oil-and-gas facility requires integrated validation of transport, cargo securing, lifting, jacking-skidding, and risk controls. This descriptive-quantitative case study triangulated Method Statement Rev.2, transport and lifting plans, manufacturer data, standards, and safety literature. The gross combination mass was 112.8 t. At a 30% grade and 3% rolling resistance, the combination required 349.8 kN tractive force and approximately 489 HP at 3 km/h, so one 400 HP prime mover was inadequate without assistance. Sixteen D13 lashing legs provided 813.7 kN horizontal capacity against 588.6 kN demand, subject to verified lashing and anchor capacities. Maximum mobile-crane utilization was 42.2%, while four 50 t jacks provided a nominal capacity factor of 3.33. The resulting framework separates verified data, design assumptions, and field hold points to support conditional-go decisions.
The integration of renewable energy systems, particularly rooftop solar panels, in industrial buildings has increased as part of efforts to improve energy efficiency and sustainability. However, the installation of solar panels on a Pre-Engineered Building (PEB) introduces additional permanent loads that may affect structural performance. This study aims to evaluate the effect of solar panel installation on the structural performance of a PEB warehouse in Medan. The analysis was conducted by comparing the existing structural condition with the condition after the addition of a solar panel load of 0.15 kN/m². A structural model was developed using structural analysis software, while the evaluation considered the utilization ratio (UR) of selected structural members, including the main column, rafter haunch, roof purlin, rafter mid span, and end wall column. The results indicate that solar panel installation increases the utilization ratio of all evaluated structural members. The roof purlin experienced the highest increase, from 0.74 to 0.91, corresponding to 22.97%, while the rafter haunch showed the lowest increase of 11.54%. The critical structural member also shifted from the main column in the existing condition (UR = 0.79) to the roof purlin after solar panel installation (UR = 0.91). Nevertheless, the maximum utilization ratio remains below 1.00, indicating that the evaluated structural members remain within their design capacity. The findings demonstrate that rooftop solar panel installation can be implemented on PEB structures with appropriate structural assessment and load evaluation.
