Rotation of Stresses in French Wheel Tracking Test

The main function of a pavement is to distribute the traffic-induced load over its different layers. While the flexible pavement design methods are based on a linear elastic calculation, the real behavior of the different layers is highly non-linear and elastic. They can also, in some cases, be plastic and viscous. This research aims to develop a three-dimensional numerical model that is closely similar to the test FWTT conditions. The model will have a real geometry wheel footprint (rather than a rectangular shape). As a substitute for incremental loading, the wheel movement during its passage over the specimen will be simulated by a horizontal displacement. These important characteristics of the model represent the novelty and the major difference between the current research and previous studies. The current model, which is based on the finite elements method, uses Abaqus software and a viscoelastic constitutive model. The materials' viscoelastic properties have been described by the Prony series, also called the relaxation modulus, which is a function of time. This parameter can be defined in most computer-aided engineering (CAE) software. The procedure for calculating the Prony series from experimental data is explained. The results obtained agree with the stress signal amplitude, the stress rotation principal, and the total displacement rotation when the load approaches the node considered and located in the middle of the specimen. Doi: 10.28991/CEJ-2022-08-03-03 Full Text: PD

Numerical Study of Wind Loads on Y Plan-Shaped Tall Building Using CFD

The increase in the population is at an exponential rate, and the available land is in the form of irregular shapes. That is why irregular shapes are very commonly built. Wind load increases with respect to height, so wind load evolution is necessary for such high-rise structures. Wind forces majorly depend on the plan's cross-sectional shape. Therefore, for an irregular shape, an investigation is needed for tall buildings. This paper demonstrates a detailed study on velocity stream line, external pressure coefficients, pressure distribution on the surfaces of the building and the turbulence kinetic energy for the Y-shaped plan for tall buildings under wind excitation for wind incidence angles of 0o to 180o. k-  turbulence model is utilized to solve the problem using computational fluid dynamics techniques in ANSYS for terrain category II as per IS: 875 (Part3), 2015. Wind ward faces in all building models show positive pressure distribution, while the leeward faces are under the effect of negative pressure distribution. Wind load can be reduced on building models by modifying the corners, such as chamfering, rounding, and double recessed. The variation of pressure distribution on different faces of a "Y" plan shaped tall building for 0° and 180° is investigated using ANSYS CFX, and the pressure contours are plotted for all the faces of different "Y" shaped buildings to compute the effect of corner modification on pressure distribution. In this research, it was found that building models with rounded corners are highly efficient in resisting the wind load. Doi: 10.28991/CEJ-2022-08-02-06 Full Text: PD

Shear Behavior of Strengthened Ferrocement RC Beams by Steel Wire Mesh

This paper investigates the possibility of strengthening a ferrocement RC beam with steel wire mesh under static loading. This experimental study included testing ten normal and high-strength concrete specimens made with ferrocement. The main parameters were the steel wire mesh layers 4, 8, and 10 in addition to the compressive strength and shear to span to depth ratio of 1.8 and 2.5. The cracking load, ultimate load, deflections, initial stiffness, energy absorption, diagonal and compressive strains, and crack pattern and failure modes of such beams were discussed. The outcomes exhibited that the beams behave linearly until they reach about 21.5% of the ultimate strength for the normal concrete beam and 23.2% for the high-strength concrete beam. The steel wire mesh presence affected the ultimate strength of the concrete beam, which increased the cracking load by an average of 15.5% for the high-strength RC beam and by 24.2% for normal-strength RC ones. The ultimate load was increased by an average of 40% for the high-strength strengthened beams and with less percentage for the normal ones, which was 31%. The  ratio affected the ultimate load-carrying capacity and maximum displacement directly, which increase  led to a decrease in the ultimate load-carrying capacity. The strengthening by steel wire mesh enhanced the initial stiffness, ductility, and energy absorption. Doi: 10.28991/CEJ-2022-08-05-04 Full Text: PD

Effect of the Mortar Volume Ratio on the Mechanical Behavior of Class CI Fly Ash-Based Geopolymer Concrete

This research described the effect of the mortar volume ratio on the mechanical behavior of Class CI fly ash-based geopolymer concrete. The absolute volume ratio parameters were designed to determine the effects on the mechanical properties of the geopolymer concrete. The volume ratio of the mortar to coarse aggregate voids (Rc) was increased by 0.25 increments, from 1 to 1.75, using constant parameters of 10 M NaOH at a ratio of Na2SiO3to NaOH (R). Furthermore, the alkaline to fly ash ratio (A) of 0.35 and the volume ratio of paste to fine aggregate voids (Rm) of 1.5 were based on geopolymer paste and mortar investigations previously published. The test results showed that 1) the Rc ratio influences the workability and compressive strength of geopolymer concrete; 2) the increase in the Rc ratio by 1.75 is not linear with the rise in compressive strength but produces better mechanical properties; 3) it does not affect the tensile strength of both geopolymer and OPC concretes; 4) the lower the Rc ratio, the higher the flexural strength; 5) the Rc ratio does not affect the OPC concrete and GC tensile strength; 6) the bond stress in geopolymer concrete with an Rc ratio of 1.75 is higher than in OPC concrete; and 7) Rc ratio does not affect the early strength of geopolymer concrete. The geopolymer concrete experienced an increase in compressive strength after 28 days, while the OPC concrete remained flat. The results will help develop an optimal mix design of Class CI fly ash with moderate calcium oxide in the production of geopolymer concrete. This will improve the future applications of using this process in new binding materials. Doi: 10.28991/CEJ-2022-08-09-012 Full Text: PD

The Influence of Nanoclay and Powdered Ceramic on the Mechanical Properties of Mortar

The amount of concrete utilized worldwide has lately grown due to rising populations and urbanization. The gas emissions during cement manufacturing and the usage of common resources result in a significant environmental threat. As a result, researchers are attempting to minimize the amount of cement consumed by using waste materials while lowering building costs. This research aims to minimize the amount of cement used in concrete by partially replacing it with ceramic powder waste while also increasing the mechanical qualities of concrete mortar by substituting cement with nanoclay hydrophilic bentonite. Mortar samples were prepared using five different replacement percentages of cement by nanoclay, including 0, 2, 4, 6, and 8%, and two replacement percentages of cement by ceramic powder, including 0% and 20%. Compressive and flexural strength tests were performed on mortar samples for 7, 14, and 28 days of moist curing. The toughness was also measured for all mixes by measuring the area under the load-deflection curve. Also, water absorption and relative densities for all mortar mixes were measured. The results show that replacing cement with 2% nanoclay and 20% ceramic powder increases the flexural strength by 11%. Doi: 10.28991/CEJ-2022-08-07-08 Full Text: PD

A Computational Approach to a Mathematical Model of Climate Change Using Heat Sources and Diffusion

The present work aims to extend the climate change energy balance models using a heat source. An ordinary differential equations (ODEs) model is extended to a partial differential equations (PDEs) model using the effects of diffusion over the spatial variable. In addition, numerical schemes are presented using the Taylor series expansions. For the climate change model in the form of ODEs, a comparison of the presented scheme is made with the existing Trapezoidal method. It is found that the presented scheme converges faster than the existing scheme. Also, the proposed scheme provides fewer errors than the existing scheme. The PDEs model is also solved with the presented scheme, and the results are displayed in the form of different graphs. The impact of the climate feedback parameter, the heat uptake parameter of the deep ocean, and the heat source parameter on global mean surface temperature and deep ocean temperature is also portrayed. In addition, these recently developed techniques exhibit a high level of predictability. Doi: 10.28991/CEJ-2022-08-07-04 Full Text: PD

Enhancement of Electrical and Mechanical Properties of Modified Asphalt Concrete with Graphite Powder

A large number of additives are introduced in asphalt concrete mixtures in purpose of improving the properties of resistance, facing the increasing traffic and more severe climatic conditions. This will guarantee the good comfort for a longer exploitation time. In this article we used graphite powder as an unconventional additive, and then investigate its effect mainly on the electrical resistivity which is in context of our research work on conductive asphalt (with a resistivity around 106 Ω m), As well as on its mechanical properties evaluated using the new Fenix test that gives many information of mechanical especially dissipated energy. A significant improvement was noticed in the reduction of resistivity by reaching 1.7 í— 106Ω m and also greater resistance to cracking based on variation of dissipated energy as a result we concluded that introducing graphite powder with an appropriate amount enhance both mechanical and electrical properties asphalt concrete. Doi: 10.28991/CEJ-2022-08-01-09 Full Text: PD

Modeling Sustainable Traffic Behavior: Avoiding Congestion at a Stationary Bottleneck

Sustainable traffic behaviour is increasing in importance as traffic volume rises due to population growth. In this paper, a model for traffic flow at a stationary bottleneck is developed to determine the parameters that cause congestion. Towards this goal, traffic density, speed, and delay were acquired during peak and off-peak periods in the morning and afternoon at a stationary bottleneck in Peshawar, KPK, Pakistan. The morning and afternoon peak periods have high densities, low speeds, and considerable delays. Regression models are developed using this data. These results indicate that there is a linear relationship between density and time at the stationary bottleneck and a negative linear relationship between density and speed. Thus, an increase in density increases the time delay and reduces the speed. I comprehensive traffic delay model is characterized by a stationary bottleneck. The Kolmogorov-Smirnov (KS) test and P-values were used to identify the best-fit distribution for speed and density. The binomial and generalized extreme values are considered the best fits for density and speed. The results presented can be used to develop accurate simulation models for stationary bottlenecks to reduce congestion. Doi: 10.28991/CEJ-2022-08-11-02 Full Text: PD

Sustainability of Suburban Industrial Development through Place Attachment

This research uses urban space reconstruction as the entry point, discussing the characteristics of residents' sense of place in Lingang new town, Shanghai, based on the method of factor analysis to divide the sense of place into place attachment, place identity, and place dependence. On the whole, residents' sense of place in Lingang new town is at a common level, and the comprehensive score of residents' sense of place in Lingang new town is "more than half". Meanwhile, place attachment is the highest, place dependence is the lowest, and place identity is in the middle. Therefore, the sense of place mainly depends on place attachment. Using an independent T test and variance analysis to explore the characteristics of the sense of place, this paper has found that age, income level, education level, household registration, and migration patterns have significantly different influences on the three dimensions of the sense of place. There is no difference in gender and the type of occupation, whether they are working in Lingang New Town or not. The research on the sense of place in suburban industrial development zones presents a new perspective for solving the social space problems in the development zone. Finally, this research suggests improving the construction of public facilities, paying more attention to youth groups' sense of place, and enhancing the sense of belonging to the highly educated groups and high-income groups, as well as strengthening innovation and entrepreneurship cooperation between the new town and the main city. Doi: 10.28991/CEJ-2022-08-07-014 Full Text: PD

Effective Use of Sacrificial Zinc Anode as a Suitable Repair Method for Severely Damaged RC Members Due to Chloride Attack

In many cases, the repair strategy by using sacrificial anodes for cathodic protection in real RC structures requires additional zinc anodes after several years due to the decreasing protective area. This experimental study evaluates the effectiveness of time lag application of sacrificial anode cathodic protection applied to RC beam specimens that deteriorated severely due to chloride attack. In the experiment, sacrificial anodes and cathodic protection (SACP) were applied to 41-year-old RC beam specimens exposed to natural marine environments in which the embedded steel bars were significantly corroded. The repair work was performed in three stages. Instant-off and rest potential tests of steel bars were conducted periodically to demonstrate the time-dependent depolarization value. In the first stage, a polymer-modified mortar as a patch repair material was cast to replace the concrete in the middle tensile part with small sacrificial anodes embedded in the mortar. After the protective current reaches an equilibrium state, the sacrificial anodes are disconnected from the steel bars for a year, defined as the second stage. During the one year in the second stage, the steel bar in the patch repair area remained passive, without any sign of corrosion. As for the third stage, additional sacrificial anodes were installed in the existing concrete part to protect the steel in it. From one year of observation after applying sacrificial anodes to old concrete parts, the time lag SACP application of both in patch and non-patch repair parts was clarified to be effective in stopping the corrosion of steel bar in both parts until 20–30 years based on the service life prediction. Doi: 10.28991/CEJ-2022-08-07-015 Full Text: PD