Innovative Carbon-Doped Composite Pavements with Sensing Capability and Low Environmental Impact for Multifunctional Infrastructures

Recently, smart composites that serve as multi-functional materials have gained popularity for structural and infrastructural applications yielding condition assessment capabilities. An emerging application is the monitoring and prediction of the fatigue of road infrastructure, where these systems may benefit from the ability to detect and estimate vehicle loads via weigh-in-motion (WIM) sensing without interrupting the traffic flow. However, off-the-shelf applications of WIM can be improved in terms of cost and durability, both on the hardware and software sides. This study proposes a novel multi-functional pavement material that can be utilized as a pavement embedded weigh-in-motion system. The material consists of a composite fabricated using an eco-friendly synthetic binder material called EVIzero, doped with carbon microfiber inclusions. The composite material is piezoresistive and, therefore, has strain-sensing capabilities. Compared to other existing strain-sensing structural materials, it is not affected by polarization and exhibits a more rapid response time. The study evaluates the monitoring capabilities of the novel composite according to the needs of a WIM system. A tailored data acquisition setup with distributed line electrodes is developed for the detection of moving loads. The aim of the paper is to demonstrate the sensing capabilities of the newly proposed composite pavement material and the suitability of the proposed monitoring system for traffic detection and WIM. Results demonstrate that the material is promising in terms of sensing and ready to be implemented in the field for further validation in the real world.

ANALISIS PENGARUH PANJANG PROFIL TERHADAP KEKUATAN HEXAGONAL CASTELLATED BEAM DENGAN METODE ELEMEN HINGGA

Castellated beam actually was an original IWF beam which is cut by several pattern and welded properly in different part to provide higher profile. There are several factors that impact the strength of castellated beam such as, opening angle, cutting width, profile length, etc. This analysis aims to determine the relationship between profile lengths of castellated beam with the strength that the profile could bear until it fully failed, also observing buckling and failure behaviour on castellated beam using finite element method. This issue is necessary due to the characteristic of steel which easily get buckled. This analysis will be assisted by modelling the castellated beam profile using finite element based program. The profile size is IWF 200x100x5,5x8 which is formed into castellated beam size 300x100x5,5x8 with various lengths such as 4 m, 6 m, 8 m, 10 m, and 12 m. The load applied was concentrated load in the middle of the span, with fixed support on both edges of the beam. The results show that the shorter beam profile provides higher strength, and an extreme buckling phenomenon occurs to the longer beam profile, also the longer beam profile fails due to pre-yielding condition, therefore the failure is caused by geometric fails. AbstrakCastellated beam merupakan baja IWF biasa yang dipotong sedemikian rupa kemudian disambung kembali di bagian yang berbeda menggunakan las, sehingga dihasilkan tinggi profil lebih tinggi dari IWF orisinilnya tanpa harus menambah material. Terdapat banyak faktor yang memengaruhi kekuatan dari castellated beam, seperti sudut pemotongan, lebar pemotongan, panjang profil, dll. Analisis ini bertujuan untuk mengetahui hubungan antara panjang profil dengan kekuatan yang dapat diterima profil tersebut hingga runtuh serta melihat pola buckling dan kegagalan yang terjadi dengan metode elemen hingga. Hal ini merupakan sesuatu yang penting untuk diperhatikan berkaitan dengan sifat baja yang mudah mengalami tekuk atau buckling. Analisis akan dibantu menggunakan program berbasis elemen hingga. Profil yang digunakan yaitu balok IWF berukuran 200x100x5,5x8 yang dibentuk menjadi castellated beam berukuran 300x100x5,5x8 dengan variasi panjang profil 4 m, 6 m, 8 m, 10 m, dan 12 m. Beban merupakan beban terpusat di tengah bentang dengan perletakan pada kedua ujung batang berupa jepit. Hasil analisis menunjukkan bahwa baja dengan panjang profil lebih pendek menghasilkan kekuatan yang lebih tinggi, baja dengan panjang profil lebih panjang cenderung mengalami tekuk yang ekstrim, dan baja dengan profil lebih panjang gagal dalam kondisi baja belum mengalami kelelehan, sehingga kegagalan diakibatkan oleh kegagalan geometris.

Comparing the Grain Yields of Direct-Seeded and Transplanted Rice: A Meta-Analysis

Conventional transplanted rice (TPR) has been increasingly replaced by direct-seeded rice (DSR) because of its low water and labour requirements. Whether and how DSR can be as productive as TPR has received widespread attention. Here, a comprehensive meta-analysis was performed to quantify the effects of direct seeding on rice yield and identify the management and environmental factors that contribute to the yield gap between DSR and TPR. The results showed that, overall, the yield of DSR was 12% lower than that of TPR. However, the yield loss of DSR relative to TPR was highly variable depending on management practices, soil type, and climate conditions, ranging from −2% to −42%. Weed and water management and climatic stress had the largest impact on yield performance, resulting in over 15% yield variation. With respect to soil properties, the yield gap can be significantly reduced by planting in areas with high organic carbon content, such as clayed and acidic soils. Furthermore, the DSR yield penalty was only 4% in a high-yielding condition compared to 14% in a low-yielding condition. All these factors indicate that optimizing management practices is necessary to improve DSR yield performance and narrow the yield gap between DSR and TPR. In conclusion, DSR could produce comparable yields to TPR but is more prone to yield losses due to inappropriate management practices, unsuitable soil properties, and climatic stresses.

Fresh concrete consistency effect on thin-walled columns creep phenomenon

A concrete structural member when kept under sustained load presents progressive strains over time, associated to the material creep. The fresh concrete consistency, specially, exerts some effect on that phenomenon. The pioneering formulations developed to modelling the creep of concrete are applicable, directly, to the cases for which the stress magnitude remains constant. Its application to reinforced concrete structural members, that exhibits changes in the magnitude of the stresses over such a time dependent phenomenon, requires simplifications from which result the memory models, whose implementation presents the disadvantage of involving the history of the stresses storage. The State Models were developed to overcome these difficulties, as they result of integral calculus scheme improvement, dispensing such computational memory storage. The subject of this work is the analysis of creep strains on reinforced concrete thin-walled columns, emphasizing the fresh concrete consistency efecct, on the base of a state model, fixing the values of its physical parameters from the NBR 6118/14 proceedings [1]. The obtained results showed the occurrence of stresses transfer from the mass of the concrete to the reinforcement steel bars, that was more pronounced in those cases for which the slump test abatement were the highest and, in some cases, including, it induced the material yielding condition.

A Second-Order Cell-Centered Lagrangian Method for Two-Dimensional Elastic-Plastic Flows

For 2D elastic-plastic flows with the hypo-elastic constitutive model and von Mises’ yielding condition, the non-conservative character of the hypo-elastic constitutive model and the von Mises’ yielding condition make the construction of the solution to the Riemann problem a challenging task. In this paper, we first analyze the wave structure of the Riemann problem and develop accordingly aFour-Rarefaction wave approximateRiemannSolver withElastic waves (FRRSE). In the construction of FRRSE one needs to use an iterative method. A direct iteration procedure for four variables is complex and computationally expensive. In order to simplify the solution procedure we develop an iteration based on two nested iterations upon two variables, and our iteration method is simple in implementation and efficient. Based on FRRSE as a building block, we propose a 2nd-order cell-centered Lagrangian numerical scheme. Numerical results with smooth solutions show that the scheme is of second-order accuracy. Moreover, a number of numerical experiments with shock and rarefaction waves demonstrate the scheme is essentially non-oscillatory and appears to be convergent. For shock waves the present scheme has comparable accuracy to that of the scheme developed by Maire et al., while it is more accurate in resolving rarefaction waves.

Application of SDS Method to Predict Fracture Toughness Temperature Dependency of A533B Steel

Recently, the authors have proposed a new method for scaling the crack tip stress distribution under small scale yielding condition and named it as T-scaling method [1, 2]. This method identifies the different stress loads for materials with different tensile properties but identical in terms of K or J. Then by accepting the knowledge “fracture stress for slip induced cleavage fracture is temperature independent [3],” a framework to predict the fracture load Pc and fracture toughness Jc at an arbitrary temperature from the already known Pcr and Jcr at a reference temperature Tr was proposed and validated for 0.55% carbon steel JIS S55C [1, 2]. This framework was named as SDS method. This paper presents that the SDS method was valid to predict 1TCT Jc temperature dependency of A533B steel [4] in the range of −9 ≤ T-T0 ≤ 27 °C, where T0 is the master curve reference temperature. The SDS method seems to have a possibility to solve the problem the master curve is facing in the relatively higher temperature region, by requiring only tensile tests.