Sustainable Issues in Infrastructure Engineering

This paper aim to investigate the effect harsh conditions have on the flexural behavior of concrete beams reinforced longitudinally with Basalt Fiber Reinforced Polymer (BFRP) bars. Finite element (FE) software, ABAQUS, is used to develop a nonlinear model capable of simulating the behavior of exposed FRP reinforced beams in flexure. Data extracted from the numerical simulations were compared with experimental data to validate the FE model. Through a parametric study, this paper aims to study the effect of reducing the modulus of elasticity on BFRP reinforced beams. The values of modulus of elasticity are reduced from the by 10%, 20%, and 30% and the impact is observed. The paper also presents comparative analysis among different BFRP tensile strength values. The analysis of the effect of varying tensile strength values on the behavior of BFRP RC beams will be conducted on an under-reinforced beam. The BFRP tensile strength value is reduced by 10%, 20%, and 30% and the impact is observed. The results show that the reduction of the modulus of elasticity of the BFRP bar decreased the flexural capacity of the BFRP RC beam proportionally. The proportional decrease was not affected by the number of reinforcement bars used in the beams with similar axial stiffness. In addition, a reduction the tensile strength of the BFRP bars caused a disproportional decrease in the flexural capacity of the beams. Beams with lower tensile strength values failed at lower deflections.

Wood, or timber, is light, cheap, and easy to transport and work with. On the contrary, reinforced concrete is more expensive, heavy & difficult to transport and slower to build. Previous research has proven that relatively cheap Casuarina Glauca wood could have sufficiently high strength that makes it a strong candidate for structural usage. In the construction field in Egypt, most of the used wood is blockboard composed from imported wood. The importing of wood represents a significant segment and Egypt invests a lot of its money in this segment, thus a research such as this one would significantly help Egypt to save money in the import business. This research aims to produce and test Egyptian blockboard made from Casuarina Glauca wood farmed in Egypt. The blockboards were produced and tested for their mechanical properties and compared to their imported counterparts. Moreover, these blockboards proved to be of a sufficiently high strength. Based on the results, this engineered wood product could be a structurally sound alternative for structural usage.

The use of Ultra-High-Performance Concrete (UHPC) in bridge construction has been growing rapidly in the last 15 years due to its excellent mechanical and durability properties. One of the areas of interest to bridge engineers is the elimination of transverse reinforcement in precast/prestressed concrete girders as it simplifies girder fabrication and result in smaller and lighter girder sections. UHPC has a relatively high post-cracking tensile strength due to the presence of steel fibers, which enhance its shear strength and eliminate the need for transverse reinforcement. In this paper, three prediction models for the shear strength of UHPC are discussed: RILEM TC 162-TDF 2003, fib Model Code 2010, and French Standard NF P 18-710 2016. Data obtained from several UHPC shear experiments in the literature was collected to evaluate the prediction models of the shear strength of UHPC girders. Comparing predicted versus measured shear strength of UHPC girders indicated that the French Standard NF P 18-710 2016 model provides the closest prediction, while the fib Model Code 2010 model provides the least scattered prediction of UHPC shear strength.

In developing countries, improvement of trafficability of rural roads, which are generally earth or graveled, are crucial for rural development. Under the circumstances with financial constraints of those countries, locally available material-based approach towards improvement of trafficability are regarded as one of the practical measures. Do-nou, which is Japanese term for soilbag, have been utilized for reinforcing base course. Do-nou method is requiring only labor even for compaction of base material and used polyester fiber woven bags for crops, fertilizer, etc. as one of geotextile. In 29 countries of Asia, Africa and the Pacific, about 180 km rural road has been improved using the Do-nou method, by the NGO which one of the authors is belong to. Because of the easiness and effectiveness of Do-nou method, it enables minor and small enterprises, generally operated by the youth, to be involved in road construction implemented by public works. In order to improve trafficability of rural roads while solving social problem, high unemployment rate among the youth in developing countries, the method needs to be adopted by road authorities for further extension. In this study, therefore, the performance of gravel road with base course consist of Do-nou have been evaluated through the series of full-size driving tests. The settlement of road surfaces with conventionally designed base course and with that consist of Do-nou with the same thickness subjected to the traffic load were measured and compared. Dynamic cone penetration index of these base course structure was also compared. Load distribution effects were also examined using earth pressure gages located on subgrade and road surface during driving tests. The mechanism of reducing settlement of road surface with Do-nou base course were verified. The performance of base course with Do-nou are defined in comparison to conventional base course structure, which enable road authorities adopt Do-nou method.

Egypt is prone to earthquakes of moderate and strong size from inland and distant seismogenic sources. The seismicity and seismic hazard studies have indicated that the country face moderate seismic hazard. Current practice in the Egyptian building code considers seismic load using seismic input from old seismic zonation map that go back to the late 90’s. Although, this map was developed using a traditional seismic hazard approach, the seismic design strategy, as well as the building code and its update; rely upon it. Also, despite the several developments in the understanding of seismicity, crustal deformation and earthquake mechanics in Egypt that have been achieved in the last two decades, also the presence of theoretical and practical developments, the current seismic load computation of the code is still dangerously adopt and recommend this map. Therefore, the current practice needs an urgent revisit and update. The main aim of this work is to estimate the ground motion parameters in the form of accessible digital maps or databases (e.g. Peak Ground Acceleration, velocity, displacement, response spectra, and time histories) that can be used as input for the next generation of the Egyptian Building code. Physics-based seismic hazard maps and/input are computed where uncertainties are properly evaluated and communicated to the end users. Also, the newly developed maps or input provide a wide range of ground motion parameters in the form of digital databases, not only limited to peak ground motion values, but comprise also excitation records, response spectra or any other ground motion parameter relevant to seismic engineering. The main delivers of this work will be archived and presented using GIS tool that covers whole Egypt with several thousands of sites (nodes), at each node/site. A geospatial database of computed time histories (seismograms and accelerograms) due to all possible seismic sources that can affect those sites are provided. In addition, at each site a representative response spectrum that envelopes all possible ground motion parameters with different percentiles are given.

Reinforced concrete beams are important supporting elements for most of the construction purposes. There are different modes of failure that can happen for beams, but this research will focus on shear failure and how we can resist the diagonal shear crack. Stirrups are an essential reinforcement in beams that can resist the shearing force. It is a closed-loop that holds the main reinforcement bars together, and it is usually installed in a vertical position. The current research presents an analytical study on the effect of using different installation positions for stirrups in beams such as; vertical stirrups (conventional technique), inclined stirrups, and a combination of vertical and inclined stirrups. The analytical study is carried out with the Finite Element Method using a software package (ANSYS APDL). A verification model is carried out at first, and compared with previous experimental work to validate the results, then the following parameters are studied: 1- Stirrups installation positions, 2- Types of Stirrups (single-legged – two-legged) 3- Angle of inclination. All beams are loaded up to failure then the failure loads, deflections, and crack patterns are obtained, also the P-delta curves are drawn for all beams.

Bridges & offshore structures are often subjected to fresh and saltwater wet-dry cycles, freeze-thaw cycles in winter, and heating cycles in summer. These environmental effects often cause steel reinforcement corrosion which can be protected using zinc coating. Zinc coating acts as a protective layer for the steel against corrosion. In this paper, the behavior of steel bars with and without zinc coating is investigated. An experimental study is performed on short reinforced concrete columns. Short 50-cm length concrete columns with square 10 × 10-cm cross-section, reinforced by four steel bars of 10-mm diameter are subjected to various weathering effects: accelerated corrosion, cycles of freshwater wet-dry, saltwater wet-dry, Freeze-Thaw (FT) and heating. Self-compacted concrete (SCC) mixes are prepared with 28 MPa average strength. A total of 20 concrete column samples are casted and divided into five groups: 1) salt water-wet-dry-uncoated rebars, 2) salt water-wet-dry-zinc-coated rebars, 3) fresh water-wet-dry-uncoated rebars, 4) heating to 70 °C, and 5) freeze-thaw samples, where 5 samples acted as a control sample and another 5 samples are subjected to accelerated corrosion. The remaining 10 samples are divided among the five groups where each group has 2 samples that are subjected to deterioration cycles. Results indicated that samples subjected to saltwater wet-dry cycles had the least strength among the five groups as expected. However, the diameter and mass losses in accelerated corrosion samples are doubled the values of that of the saltwater dry-wet cycles with the same mean strength.

Foamed bitumen stabilization is a useful and well established method for improving crushed rock and natural gravel materials for pavement construction. Like most pavements, those with a foamed bitumen base course (FBB) are usually designed using layered elastic softwares in which the FBB layer is characterized by an elastic modulus and a Poisson’s ratio, with the modulus having a significant influence on pavement thickness. In Australia, FBB characterization is based on the saturated indirect tensile modulus after three days of accelerated curing of samples produced in a laboratory mixer. It is well established that this approach to FBB characterization is not representative of field production and in-pavement curing conditions. To determine the effect of FBB production and curing on FBB modulus, pavement thickness and predicted pavement life, the same FBB was produced using a laboratory mixer, an exsitu pugmil and an insitu stabilizer. Material was sampled and the uncured, cured and saturated modulus was measured after various periods of accelerated laboratory curing. The exsitu produced FBB was also cured using simulated in-pavement conditions. The various FBB modulus values were then used to determine the required thickness and predicted life of a typical aircraft pavement including a 300 mm thick FBB layer. It was found that field produced FBB modulus increased significantly during the first 90 days after production and that laboratory production and curing protocols were not representative of field production and in-pavement curing conditions. Layered elastic pavement modelling showed that more than 80% of the predicted pavement damage occurred in the first 20 days after FBB production. It is therefore recommended that FBB remains untrafficked for 7–12 days after production, wherever possible, and thinner pavements are likely to perform adequately in situations where the FBB is protected from traffic loading for more than 14 days following production.

Reducing the environmental impact and enhancing the properties of concrete is of great significance environmentally and economically. Using sustainable construction materials coming from construction wastes like recycled concrete that comes out from demolishing or renovating of existing structures could help in producing sustainable materials of good quality and low cost. The use of recycled concrete improved the concrete quality and enhanced the mechanical and microstructural properties of concrete. Tests and research done on this type of sustainable concrete proved the applicability of usage of recycled concrete aggregates as a full replacement of coarse aggregate by using different grain sizes of natural and recycled coarse aggregates. The desired concrete strength as per the concrete mix design is 35 MPa with fixed water to cement ratio of 0.48. The concrete mechanical properties increased clearly after replacing the natural coarse aggregates by recycled concrete aggregates. This research studied the concrete density, workability, temperature, compressive strength, split tensile strength, flexural strength, and microstructural analysis; which is the main focus of this paper.

Across the different parts of the world, the concept of Green Building is catching attention of the architects, urban & town planners, engineers and even the common people. According to the experts, Green buildings are the ones that benefit the environment as well as the human beings by minimum waste generation at all the stages of its life cycle while being cost effective, sustainable and providing comfort to the humans. The presence and behaviour of consumers in the buildings impact largely on energy utilization of various devices such as artificial lights, air conditioners, heaters, etc. Building’s designed energy performance can be affected to one-third by unaware energy usage behaviour. To save the energy, the research team has carried out a pilot study in the Civil Engineering Department (CED), SVNIT, Surat by combining the concepts of Energy Performance and Value Engineering. All the lights in the passage of the department, for the both the floors, were replaced with the sensor lights with specifically designed automated fixtures by referring Energy Conservation Building Code (ECBC) 2017, Bureau of Energy Efficiency (BEE), MoP, GOI. The results obtained showed unmatchable tangible benefits and proved that by implementing the same at the institute level can prove to save considerable amount of cost, water used to produce electricity and also reduce the carbon foot prints. As per the analysis, the annual kW usage reduced to 54.02 kWh from 262.8 kWh, saving 79.44%. The resulting total annual saving is estimated to be 208.78 kWh. The outcome of this research will be useful for administration of the Institute. Furthermore, the Institute is demonstrating this pilot building for energy performance study to the networking institutes, students and faculty members as well as policy makers, planners, developers and end users.

The over dependence on road transport system to cater for the fast growing human population in some developing countries like Nigeria has necessitated the need for the development of an efficient and sustainable road pavement management system. This study used data mining techniques namely; Random Forest, Decision Tree and Naive Bayes algorithms to examine the inferred dataset on flexible road pavement performance attributes and surface condition classification in Nigeria. The data mining techniques were used to investigate hidden relationship between pavement performance variables and to authenticate the accuracy of subjective measurements that were used for pavement surface condition classification. The Random Forest and Decision Tree algorithms reported perfect classifications of road pavement sections into; Excellent, Good, Fair, Poor and Very poor. On the other hand, the Naïve Bayes algorithm yielded inaccurate classifications with some margin of errors which were attributed to missing and noisy entries in the dataset. This necessitated the use of Fuzzy logic theory for the performance prediction due to its capability to handle the imprecise dataset. It was used to develop Fuzzy Inference System (FIS) for performance prediction of flexible road pavement using attributes such as; the classified Initial Pavement Condition (IPC), Age of pavement, Resilient Modulus (M_R) of subgrade soil, Average Truck load per day, Average Annual Air Temperature and Rainfall to predict the Future Pavement Condition (FPC). The model was calibrated using the observed logical behaviour of road pavement to fit the engineering experience and judgement. A goodness-of-fit test between the observed and predicted FPC values showed high level of consistency – correlation coefficient at 90%. The research proposed 5120 mutually exclusive Fuzzy Logic Rules for performance prediction of road pavement based on permutation theory. Though, the required well-spread dataset for calibration of the model to cover all possible pavement conditions in Nigeria and subsequent validation were not available, a framework for performance prediction of flexible road pavement was developed, and a comprehensive guidelines on how to calibrate the FIS model using well-spread dataset was presented.

Approach slab is a structural concrete slab that spans from the back wall of the abutment (i.e. end of the bridge floor) to the beginning of the paving section. The purpose of the approach slab is to carry the dead and live loads over the backfill behind the abutments to avoid differential settlement that causes bumps at the bridge ends. Cast-in-place (CIP) concrete approach slab is the current practice in most of the states in US with various spans, reinforcement, thicknesses, and concrete covers. However, it has been reported that most approach slabs experience cracking and settlement, which result in premature deterioration and shorter service life. The replacement of deteriorated approach slabs causes costly and long traffic closure and detouring. Precast concrete (PC) approach slabs is a promising solution that could provide longer service life and accelerated construction/replacement. This paper presents a literature on current approach slab practices and innovative precast concrete solutions. Also, an analytical investigation is conducted using finite elements to evaluate the performance of the current approach slab practices in the state of Nebraska. Several parameters are considered in this investigation, such as volume changes due to shrinkage and temperature changes as well as skew angle and bridge width. Analysis results indicate that volume changes cause high tensile stresses along abutment line, which results in longitudinal cracks. Also, high skew angles result in stress concentrations at the slab corners and the increase in slab width increases the stresses in transverse direction.

Coarse and fine aggregate constitutes approximately 93% of dense graded airport asphalt and the aggregate properties can affect asphalt surface performance. Despite a general trend towards performance-related specification of asphalt mixtures, prescriptive aggregate properties are generally still retained. This primarily reflects the absence of reliable performance-based laboratory test methods for determining the effect of aggregates on asphalt weathering and erosion. Historical airport asphalt specifications included a broad range of aggregate durability properties and the aggregate supply industry has questioned whether coarse aggregate durability testing can be simplified to combinations of just two properties. To determine whether a reduction in aggregate durability testing is appropriate for Australian airport asphalt, eight sources of aggregate were tested for wet strength, wet-dry strength variation, Los Angeles abrasion, sodium sulphate soundness and water absorption. The different tests were associated with different levels of variability and the correlation between the various tests results was generally low, except for Los Angeles abrasion and wet strength. The industry recommended combinations of aggregate durability testing were found to be inconsistent and ineffective. Consequently, the current range of aggregate durability tests must be retained. The only exception was the potential to omit Los Angeles abrasion when the wet strength is high. Furthermore, there was no significant difference between the results associated with the various coarse aggregate fraction sizes, indicating it may be appropriate to allow only one sized fraction per quarry source to be tested. Further work is required to correlate the various aggregate durability tests to asphalt field performance.