Structural Materials Commons^™

Experimental Research On Anti-Uv Aging Performance Of Tire Pyrolysis Carbon Black （Tpcb） Modified Asphalt, Yang Wansheng, Yi Shuaibing, Dai Tianle, Li Tiantian, Gan Youwei

Journal of China & Foreign Highway

To investigate the anti-ultraviolet （UV） aging performance of waste tire pyrolysis carbon black （TPCB）-modified asphalt，TPCB-modified asphalt was prepared and subjected to UV aging tests alongside the base asphalt at various intervals.The micro changes and surface roughness of two kinds of asphalt surfaces were studied by atomic force microscopy （AFM）.The behavior changes in ductility，softening point，and penetration of two asphalts before and after UV aging were tested by asphalt performance tests.The results show that the reduction height of TPCB-modified asphalt is smaller than that of base asphalt，and the surface roughness is larger than that of base asphalt at each time.The performance change …

Structure And Material Of Rigid‑Flexible Composite Pavements And Development, Liu Zhaohui, Huang You, Yu Shiqing, Liu Jingyu, Li Sheng, Liu Li, Pan Yu

Journal of China & Foreign Highway

The rigid-flexible composite pavement，as a kind of durable pavement structure，has been widely used for heavy-duty traffic，special geological conditions，bridge tunnel paving，etc.In order to promote the application of durable rigid-flexible composite pavements and clarify the key research issues and development directions，relevant research progress of rigid-flexible composite pavements in China and abroad was reviewed.Based on the structure design theory and construction technology of rigid-flexible composite pavements，the structural mechanical behavior characteristics of rigid-flexible composite pavements were described，and the stress induced by load and temperature of asphalt surface layer and rigid base layer，as well as their interactions were analyzed.The asphalt surface layer on the rigid …

Experimental Study On Double‑Mixture Solidification And Ratio Optimization Of Dredger Fill Sludge, Qin Liang, Chen Zhimin, Lu Yongfei

Journal of China & Foreign Highway

In order to study the optimal r atio of cement and calcium oxide by double-mixture solidification for improving dredger fill sludge，the soil modification results by double-mixture solidification were analyzed based on orthogonal experiments.Finally，the fuzzy comprehensive evaluation method was used to quantitatively optimize each ratio scheme.The results show that：① Under the same addition ratio （addition amount of 1.0%‒4.0%），there is a positive linear correlation between the optimal moisture content and the addition amount，and there is a negative linear correlation between the optimal moisture content and the maximum dry de nsity.Under non-equal addition ratios，the law is not obvious.However，compared to cement，the water-reducing effect of …

Road Performance Of Reclaimed Asphalt Mixture Mixed With Bagasse Fibers And Rubber‑Modified Asphalt, Jiang Xin

Journal of China & Foreign Highway

Given the potential resource value of rec laimed asphalt pavement，waste rubber powder，and bagasse fibers，it is meaningful to develop the cooperative utilization of various solid wastes.This paper studied the microstructure and thermal characteristics of bagasse fibers，carried out the mix design of a reclaimed asphalt mixture with bagasse fibers and rubber-modified asphalt，and evaluated its road performance.At the same time，the test road was paved successfully and observed for a time.The results show that the hollow lumen with multilayer fiber structure in bagasse fibers contributes to absorbing free asphalt in mixtures and enhances the adhesion between bagasse fibers and asphalt.The thermal properties of bagasse …

Feasibility Of Sandstone Used In Asphalt Pavement Of Expressways, Lou Jianmin, Meng Xiandong, Song Zhike, Zhao Lidong, Bai Julong, Zhao Shengli, Zhu Jishuang

Journal of China & Foreign Highway

In order to explore the feasibility of applying sandstone in the asphalt pavement of expressways，the physical and mechanical indexes of sandstone and limestone aggregate were compared，and the high temperature performance，low temperature performance，and water stability of asphalt mixture were studied from the aspects of grading type，asphalt type，and aggregate lithology.The results show that the road performance of asphalt mixture synthesized by clean and regular sandstone aggregate meets the requirements of current specifications.At the same time，the comprehensive road performance of sandstone asphalt mixture with 1% anti-stripping agent has been improved.

Key Construction Techniques For Emended Cap Unsealed Bottom Of Deep‑Water Hard Rock, Zeng Jian, Guan Xiaohui, Guo Zhiwei

Journal of China & Foreign Highway

In the construction of a deep-water embedded cap foundation，it was required to excavate the mud surface to the depth below sealing concrete and clean the bottom carefully，ensuring the height and quality of bottoming concrete.For hard rock under good geological conditions，there exist such problems as difficulty in excavation，long excavation time consumption，and high construction cost.Based on the construction of the main pier caps of the Chongqing Jiahua Metro Bridge，this paper adopted the method of combining theoretical analysis，numerical calculation，and engineering implementation verification，which developed an emended cap unsealed bottom key construction techniques for deep-water hard rock.This construction technology used the method of excavating the …

Influence Of Blasting Point Position And Foundation Pit Height On Blasting Vibration During Foundation Pit Blasting Excavation, Liu Kuan, Xu Zhihao, Tang Yuan, Shen Jun, Bao Xiaohua, Shen Pinghuan, Ou Yang

Journal of China & Foreign Highway

In view of inaccurate vibration prediction of foundation pit blasting，the influence of blasting point position and foundation pit height on vibration during foundation pit blasting excavation was studied by using finite element simulation software.First，based on the foundation pit blasting excavation of the Mawan Cross-Sea Passage，a numerical simulation was carried out to verify the applicability of the model.Then，under unchanged blasting center distance，the distance from the blasting point to the edge of the foundation pit and the foundation pit height were changed respectively，and the influence of these two factors on surface vibration was studied.The results show that a greater distance from the …

Excavation Method For Ⅴⅴ‑Grade Surrounding Rock Of Double‑Hole Eight‑Lane Super‑Long‑Span Tunnel, Shi Youzhi, Liu Xudong, Yong Jinzhu

Journal of China & Foreign Highway

In order to reduce the adverse effect of back heading blasting on the completed supporting structure at the entrance of a double-hole eight-lane super-long-span tunnel with Ⅴ-grade surrounding rock，the Niuzhaishan tunnel project in Pingtan was taken as an example.The original design of the double-side heading method is easy to cause the collapse of the temporary steel support that has been completed when blasting happens near the back heading.In view of this，this paper put forward scheme 1 of canceling the temporary transverse support and the up-and-down step method with vertical support （scheme 2）.It then used the finite element method to calculate …

Design And Evaluation Of Land‑Saving And Beautiful Median Barriers, Li Jingjun, Wa Ng Xin, Qi Jie, Wang Zijian, Liu Siyuan

Journal of China & Foreign Highway

During the construction and expansion of expressways and national and provincial highways，more diversified requirements have been put forward for the median barrier，including reliable protective performance，small footprints，beautiful traffic environments，and economic costs.However，the existing median barrier achievements still have some shortcomings.In order to better meet the design and use needs of median barriers for highways，theoretical analysis，computer simulation，and full-scale impact tests with real vehicles were adopted，and the force characteristics of different types of median barriers were analyzed.A new design concept of beam-column integration was put forward.Through systematic research on the barrier height，width，beam，column，foundation，and other structures，a land-saving and beautiful median barrier was developed.The median barrier had …

Multi-Region Plane Fitting Algorithm For Texture Depth Of Asphalt Pavements, Zhu Feng, Feng Xingle, Wu Chuan, Lin Xiaoyong

Journal of China & Foreign Highway

The existing calculation methods for texture depth of asphalt pavements are easily affected by external and human factors.Therefore，a multi-region plane fitting algorithm for the texture depth based on three-dimensional （3D） linear laser data was proposed.The algorithm preprocessed the collected 3D height data matrix of the pavement and derived a slope-based adaptive filtering algorithm for point cloud data.Then, the 3D height matrix was divided into multiple regions，and the local extremum of the center point was determined.Finally，with the three-point and one-surface plane fitting algorithm as the core，the texture depth of asphalt pavements was calculated.The experimental results show that the correlation between this …

Key Technology And Numerical Simulation Of Cast‑In‑Place Construction Of Main Arch Ring Of Reinforced Concrete Arch Bridge Based On Suspension Steel Arch Method, Su Xueping, Xia Zhengzhi, Lyu Songgang, Duan Pengjie, Lyu Yigang

Journal of China & Foreign Highway

Steel arch frame replaced such construction methods as floor bracket or segment cantilever assembly and it was applied to arch circle cast-in-place across deep water canyons in mountainous areas，which had certain advantages and was worth promoting and applying.By introducing the key construction technologies of Sanchahe Bridge，including steel arch frame cantilever fastener method assembly，arch water tank method precompression，and main arch ring layered pouring，the common problems in the construction process of crossing the deep water canyon were solved effectively.Based on Midas Civil overall modeling of finite elements，the key construction technologies adopted by the bridge were numerically simulated and analyzed，and the successful construction …

Guardrail Improvement For Old Bridges In Expressways, Liu Xinping, Zhang Shihui, Shang Zhongping, Han Yue, Zhang Qiang

Journal of China & Foreign Highway

In view of the insufficient protection grade of the guardrail in old bridges，a combined guardrail suitable for the low concrete wall guardrail in the old bridge was designed and developed by using finite element analysis while not damaging the main structure of the bridge.The protection grade was verified to reach SA grade through a full-scale vehicle collision test.The guardrail was designed with new high-strength alloy steel，with light weight and beautiful appearance.There was no need to dismantle the original concrete foundation in the old bridge，which is convenient for construction and requires low cost.Therefore，it is worth being popularized and applied in the …

Improvement Of Gravelly Laterite And Cement Stable Disposal In West Africa, Jin Haibing, Yi Zicheng, Zhuo Rong

Journal of China & Foreign Highway

Owing to poor gradation and high liquid limit and plasticity index，the application of gravel laterite on road paving is limited in West Africa.To overcome this issue，laterite granule combined with sand at different content was explored.The performance including the particle composition，limit water content and CBR value was investigated.The results indicate that sand treatment can improve the gradation，enhance the compactness，and reduce the plasticity index.The improved gravel laterite can meet the requirements of subbase，cushion，and base courses.Cement treatment can improve the mechanical properties of laterite grains.Cement and sand content affect the unconfined compressive strength significantly，with an optimal sand content range identified.Specifically，laterite granules mixed with …

Micro-Mechanical Characterization Of Uhpc Stiffness Mechanisms: Towards A Better Understanding Of Concrete Elastic Modulus, Charissa N. Puttbach

Graduate Theses and Dissertations

Current design code equations for estimating the elastic modulus of specialty concretes like ultra-high performance concrete are not all suitable. Developing empirical curves from exhaustive experimental testing is challenging for concretes that may have high levels of cement replacement with mineral admixtures and fibers at varying volume contents. As such, an alternative approach is taken that seeks to understand the constituent microscale stiffness mechanisms and relate the results to the macroscale. Micropillars are fabricated on several cement paste phases using a focused ion beam. A modified pico-indenter is used to determine the linear and non-linear behavior under micro-compression loading. Micropillar …

Numerical Simulation Of Laser Induced Elastic Waves In Response To Short And Ultrashort Laser Pulses., Alireza Zarei

All Dissertations

In an era of intensified market competition, the demand for cost-effective, high-quality, high-performance, and reliable products continues to rise. Meeting this demand necessitates the mass production of premium products through the integration of cutting-edge technologies and advanced materials while ensuring their integrity and safety. In this context, Nondestructive Testing (NDT) techniques emerge as indispensable tools for guaranteeing the integrity, reliability, and safety of products across diverse industries.

Various NDT techniques, including ultrasonic testing, computed tomography, thermography, and acoustic emissions, have long served as cornerstones for inspecting materials and structures. Among these, ultrasonic testing stands out as the most prevalent method, …

A Manufacturing-To-Response Pathway For Manufacturing Optimization Of Carbon Fiber Reinforced Polymer Composite Structures, Madhura Limaye

All Dissertations

Over the past decade, there has been an increased adoption of thermoplastic and thermoset based continuous carbon fiber reinforced polymer (CFRP) composites for structural applications in several industries. Among the different manufacturing methods, thermoforming process for thermoplastic based continuous CFRP’s offer a major advantage in reducing cycle times for large scale productions. Similarly, out-of-autoclave curing process for thermoset based continuous CFRP’s using heated tooling enables production of large composite structures. However, these manufacturing processes can have a significant impact on the structural performance of parts by inducing undesirable effects. These effects include inhomogeneous fiber orientations, thickness variations, and residual stresses …

Surface Treatments' Effects On The Capacitor's Dielectric Performance Under Electro-Thermal Stresses, Haider. M. Umran, Feipeng Wang

Karbala International Journal of Modern Science

Biaxial-oriented polypropylene (BOPP) films are characterized by unfavorable aging behavior because of their poor susceptibility to high temperatures, humidity, and high electric fields. This makes them unqualified to withstand harsh operating conditions, such as in capacitor applications. This study investigates the impact of annealing BOPP samples at 100 °C for five hours after fluorination at different times (15, 30, and 60 minutes) on their electrical and mechanical performance under electro-thermal stresses. Scanning electron microscope (SEM) images confirm that there is an increase in surface roughness and the formation of a dense layer of fluorine-containing groups monotonically with fluorination time. So, …

Adopting Information System Technologies In Construction Project Management, Hadi Haikal

Harrisburg University Dissertations and Theses

The construction sector has remained late in integrated information systems' adopting process to perform the system improving processes. Lack of adoption of technology has been a root cause of the early issues they faced, such as budgetary and scheduling overshoots, quality defects, safety occurrences, and generally poor communication and coordination among the stakeholders. This research looks into the benefits and challenges, the key success factors, and the implications of using an array of information systems, including building information modeling (BIM), artificial intelligence (AI), Internet of Things (IoT) sensing, and enterprise systems, to comprehensively address issues in project management in construction …

Testing Of Recycled Polypropylene As A Viable Structural Material (Quarter 2), Isabella Jimenez-Melendrez, Katherine Timbes, Jocelyn Embleton, Tauni Dela Cruz, Zyra Kingston, Emily Byrd, Jacob Stinger

Architectural Engineering

5.25 trillion plastic particles have been found in the oceans each year, 3 million water bottles are consumed each hour, and one million plastic bags are used each minute in the United States of America (Williams). The vast majority of conventional plastics such as polyethylene, polypropylene, polystyrene, and more, are non-biodegradable (Tokiwa). To make matters worse, 70% of this non-biodegradable plastic is discarded into landfills and inevitably makes its way into the environment (Williams,). Plastic products have become vital to the United States economy due to their many uses in the construction, packaging, transportation, and health care industries. However, this …

A Comparison Of Beamforming Characteristics In Isotropic And Composite Plate Structures For Use In Structural Health Monitoring, Sarah Ketchersid

Doctoral Dissertations and Master's Theses

Structural health monitoring in plate-like simple structures using phased array beamsteering of guided Lamb waves is useful in damage detection and evaluation efforts. Lamb waves can be effectively used for beamsteering using a linear array. The experimentation primarily focuses on beamsteering in the aluminum panel, which involves developing a simulation based on extracted data to visualize the dispersion of waves across the panel. By evaluating parameters such as slowness, velocity, and amplitude direction and variation for a specific metallic plate, the wavefront generated by a single wave source can be represented as a function of propagation angle and distance from …